ERV/HRV vs Dehum - What’s the difference?

[@coasttal123]

Matt, as a mechanical engineer, I only want one item in a very tight home bringing air into the house. Therefore I spec an ERV for that. I also recommend dehumidifiers for the interior of the home that are fixed in the home and drain to the plumbing system, but do not connect the air stream to the exterior. Also, I pull air from all bathrooms, kitchen, and peak of vaulted ceilings and exhaust them through the ERV. I put the fresh air into the large common areas where no one will sit, since that air may be a bit cooler or warmer than the air in the house. This strategy has worked well in design and works well in my own home. I do engineering in the southeast US.

[@jeffzhang3144]

hi could you share your contact info? Need to design a system for a new construction home. Thanks

[@glike2]

What's a good ERV for a Southern California coastal small family home?

[@anando005]

Glad to see this video. Recently put an ultraire dehumidifier in my house because my builder didn’t despite having unvented attic and entire house is spray foamed. I will say in last day or so we noticed we are much comfortable at 73-74 as opposed to having to keep temps at 70 prior to installing the dehumidifier I’ve learned a lot from your videos and helped me make sure my builder wasn’t taking short cuts.

[@StevePatak]

Matt, Would love to see a video that involves retrofitting a system into an existing home with multiple HVAC zones that goes through the considerations and complications of trying to make something fit with existing equipment.

[@bchilva]

How do you install both systems? Are they on a separate duct system together? Would like you to do a video on how these are both installed

[@megacleancab256]

I live in Central Florida. I just had the insulation 2.0 system and the UltraAire 98. Dropped my bill by 1/2. We work from home and were very worried about indoor air quality. Glad I watch you and this old house.

[@sameinsohn6187]

Solid! I’m doing the same thing DIY in Miami area. Hoping for same results.

[@BlackEagle540]

Hi Matt, we live in desert high plains northern Nevada. We want the circulation but really want more humidity as we have vaporizers right now. What do you recommend?

[@chadwhite2736]

Great video Matt. We build in Northwest Arkansas and have all four seasons with times of high humidity. It was not until we spent three years in Arizona that I understood Comfort was not tied to temperature but rather humidity. We would leave our AC at 78° and be more comfortable than 70° in a high humidity area.

[@jeremylourie5270]

Hello, fellow NWA brother.

[@seanschommer]

Chad who did you use for your HVAC who understood ERV and dehumidifiers. Getting ready to build tight home full envelope including attic. Getting some push back from HVAC that doesn’t think a ERV and dehumidifier is necessary. thanks. We are also in NWA.

[@PaulyDownUnder]

Matt, if running both, an ERV and Dehumidifier, how would you duct them? Would you keep them complete separate or join them together, does the ERV feed the Dehumidifier or vice versa?

[@toomanymarys7355]

I'd personally put the dehumidifier on the H/AC and the ERV separate....

[@fishbowl7098]

As a Realtor,love this channel for learning!

[@seikibrian8641]

On another type of learning topic: remember to put a space after commas and other punctuation marks.

[@juanjoseamador7614]

Purchased: August 2022 - still works GREAT! kzbin.infoUgkxxsUnXhGsSJLim_XnMHyQK0u3XVaW-CGn I live in a studio and during the summer it gets scorching hot - really old building with no ac units. I can’t express how EASY it was to install.This unit has been a life savior during the summer and some days during other seasons where it can still be a bit warm at night. In this small place is my friend, a husky, poodle mix and myself. We need AC - lolI don’t use the dehumidifier option - I’m not sure if it will leak in my house, since I did not install the small draining hose that came with it. May look into it late but I don’t worry about much humidity in the apartment.I don’t understand why the negative reviews since all things mentioned, I personally did not find issues with. Definitely worth it!

[@ParabellumX]

Great explanation, Matt. Thanks for the video! You couldn't have been any closer to the truth when you said that every home down here in the south needs a dehumidifier. When I purchased mine, it was literally my best investment ever.

[@carterdjohnson9673]

Matt, we recommend installing the ERV/HRV and taking the bathroom air back to the unit with a UV light in the airstream before the coil. Some people in the area like to add the dehumidifier also, however that is on higher-end homes where more space for mechanical is available. In mid-range to low-cost housing, we generally use the A/C system as the dehumidifier like in a car as the retrofit in the controls package, changing the humidity levels based on air-changes and base temperatures. This can work for home and commercial systems.

[@bobbygetsbanned6049]

UV light creates ozone which you don't want to breath...

[@carterdjohnson9673]

@Bobby Gets Banned Small amounts of Ozone are not harmful. No, UV-C light does not produce ozone. However, the shorter Ultraviolet-V (UV-V at 185 nanometers) wavelength of UVV light actually generates ozone. This occurs because UVV light reacts with oxygen to break it into atomic oxygen, a highly unstable atom that combines with oxygen to form O3 (Ozone).

[@charlespaine987]

@@bobbygetsbanned6049note there are UVC SOURCES in the correct wave lengths that still actively disinfect without producing ozone. Technology marches on sometimes.

[@swampcastle8142]

AC systems used as dehumidifiers are either undersized on purpose so they run continuously or add a large resisrance heating coil to reheat the air to force the AC to run longer. Both bad ideas. The first is hard on the equipment and can't keep up during heat waves, and the second just blows out the monthly bill to run it. A dedicated dehumidifier works the best.

[@jasontoolan3816]

Thank you Matt, for sharing how we can reuse conditioned air. On the path to a more regenerative future.

[@pkla14]

Thank you so much for going over this. I literally ran into a house today that the engineer advised putting ERVs in. The house already had humidity problems (it’s over 70%) and this is in Tropical climate (Miami area). I told the client exactly what you’re saying.

[@Furiends]

Yep for hot and coastal everything matt is saying is super valid. Up here in the northern parts though this makes very little sense. There are a lot of options for managing humidity with an AC including distributing out the time it runs. I wish that context was given in the video. Builders should be using vary different systems depending on the climate.

[@UltraAireDehumid]

@@Furiends We absolutely agree that systems need to be designed and sized differently for different climate zones. The challenge no matter where the home is located (in a green grass climate) is counting on the A/C to dehumidify to the desired RH all the time. As you know, Hvac systems are sized based on peak load conditions, which most homes see only 1% of the time. There are systems that ramp down to remove more humidity but they are still over cooling to dehumidify leading to comfort issues. Typically in climate zones 4,5,6 (northern) the AC does not run enough during the spring, parts of summer, and fall to always be able to handle the moisture loads. We are actually seeing this more and more in the South as homes are being built tighter tighter. Dew points can get just as high in Minnesota as they do in Miami - they just don't last as long. Plus, people generate a lot of moisture in the home. During the spring and fall this is a double whammy with little to no A/C running. We truly believe that the AC system should be designed to remove as much water as possible when it is running (without over cooling), that fresh outdoor air should be brought in to the home when people are home to ensure good indoor air quality (no matter what the conditions are outside), and a dedicated dehumidifier should be used to control the moisture during the times the AC can't (spring, fall, evenings, rainy times, etc...). We all know that homeowners do not live in their homes and operate their systems like we design them to. Moisture is the number detriment to buildings and our comfort and health. Not saying every home in the northern climates needs a whole house dehumidifier but they most likely will need some sort of dehumidification, especially in a basement or crawl space, which will help control the humidity in the rest of the home also.

[@Furiends]

@@UltraAireDehumid There's a lot of systems to go over so I'll just give an example of what I am talking about. Also I want to reiterate it isn't just sizing systems its carefully designing them for a space down to the exact air flow. It makes a massive differences if they'll work or not no matter how big the system is. As an example lets say a home is built tight with an HRV which maximizes dehumidification and an HVAC humidifier options in a temperate climate zone. Meaning most of the time the humidity outside is at or lower than the target humidity. The AC can lower the humidity at least when it runs. The AC even with constant flow can run for shorter lengths of time to dehumidify more and the HRV can circulate more to lower the humidity and this will be at the more moderate temperatures of the year. Thats it you're done. You don't need a massively complicated system. Mainly you need the wiggle room to not be wasting lows of energy reheating or cooling duct work and to not have a super leaky house that would have a hard time during the summer. Depending on exact locations the challenges are different. It's a consequence of a minisplit system used in a mostly hot climate that you really need central circulation to keep things dehumidifying as suggested in the video for example. Forced air is probably a better solution in terms of cost effectiveness in a hot humid climate.

[@sickre]

Its great that code requires fresh air coming into houses - I live in Eastern Europe and apartments here are just built as completely sealed boxes. I need to keep my balcony door constantly ajar to let in fresh air. Alternatively some apartment blocks have poorly designed communal ventilation system, which just distributes noise and cigarette smoke into other apartments!

[@activechaos128]

🤣🤣🤣

[@bigpjohnson]

Concrete apt buildings are usually fairly sealed up in order to contain fires, so many buildings dont have sprinklers or fire alarms or anything. I'm from over there as well, and yes everyone cracks open a window to get some circulation going. After living in the US with forced ventilation and ceiling fans, it feels so weird to go back there to just stale, non-moving air!

[@altergreenhorn]

You must live in some awkward region/country because that ain't normal only if you live in an old apartment building were was some renovations in the near past but not complete ones

[@ElAnvaBar]

Thats a case of shitty building code. Then again if it is from the USSR - period. It is an old defect. Adding ventilation vents in the window frames when upgrading from single to doube glass (if you haven't already) will help some. Now if you then use CO2 controled vents and a heatpump return air - unit. Then you're energy friendly and well ventilated. A full on balanced ventilation system with heat recovery (and summer-night ventilation) is a tough job to build into an existing apartment, and expensive. (Both ways are expensive though)

[@samplumbe3288]

Hi guys vent axia do a simple mechanical ventilation heat recovery MVHR unit that is a simple through wall fan unit. This could be installed in an old building.

[@austinselleck9484]

Northwest Arkansas- I’ve seen humidity in the single digits when it gets cold for awhile in the winter. During the summer that’s a different story. Not uncommon for humidity outside to be over 90%. In this case I like the idea of a dehumidifier

[@SubStationSparky]

Matt, I have about 62% humidity in the winter in the house after many HVAC/insulation upgrades (Central Connecticut) I have ductless mini splits but rely on them for heating in the winter I’m gonna put in a Panasonic Select exhaust fan running 24hrs @about 40cfm in the bathroom (centrally located) hopefully that will fix some humidity issues.. from there if I continue to have issues I will have to install a stand alone dehumidifier like one in your video here.. THANKS!!! Great VIDEOS!!!

[@mikeisnumber58]

Thanks Matt. Love that you talked about how to use them in conjunction with each other.

[@compactc9]

Watching your videos has convinced me that I'll likely have to build my house to get what I want. One of the big items is the HVAC, I think my personal preference leans towards radiant ceilings and some kind of ducted system to circulate purified outdoor air to keep the IAQ controlled. I have terrible allergies, hate high humidity, and love feeling cold.

[@christinearmington]

👍❄️

[@JohnWeland]

Man, I am living in Minnesota and we hit 80% humidity in the house from spring until early fall. 90 degrees in the summer too. Its as bad as Houston (son of Texas here). We are looking to downsize our home, I think I want to do something like this in whatever we buy.

[@vennic]

I'm in MN too, do you try not to run the ac or open the windows at night? Running the AC is your best bet to dehumidify in the summer, but with old leaky houses it's hard to keep up

[@JohnWeland]

@@vennic our ac barely keeps us below 80 inside on the hot days. (Really drafty old house and weird ass ac outside the envelope.

[@vennic]

@@JohnWeland gross man you have my condolences

[@tbthedozer]

Lol I’m a Minnesotan too. Looks like talking some sort of weather either inside or outside is our lot in life. Anyway was anyone else thinking about the dehumidifier in the spring mornings when the dew makes your blanket feel like a wet towel? But I don’t want to add the heat of the dehumidifier after all we like I cool here. If there was a 3rd vent on the unit the waste heat could be pushed outside when it wasn’t needed. And using the damp morning air across the condenser would help the efficiency, right?

[@vennic]

@@tbthedozer I've read higher humidity generally helps with heat exchange. I'm planning to install a heat pump water heater in series with my gas unit for this very reason. Dehumidify the basement more efficiently in the summer, no waste heat

[@markrevette1067]

So this would be in addition to a whole house AC systems ? I am planning a house build in a year or 2. I live in upstate NY near the Canadian border. As you can imagine, a good portion of our time is in the heating system when the air gets pretty dry and people tend to use humidifiers. But then, we do get a few months in the summer when it can get warm and humid (probably not compared to Texas & Florida standards) and many people will use window AC units. I would prefer a central AC system in the new build. Just trying to do my homework to address both extremes we experience up here.

[@andreycham4797]

if your plan to burn lots of dough , buy CERV ll You get more use out of HRV with a heat pump built in in your climate

[@guytech7310]

If your new home is tight, you make have excessive humidity during the winter. Dry\low humidity occurs in leaky homes as warm air carries the moisture out. In a tight home that does happen and most homes have a lot of moisture sources: bathrooms, Kitchens (Dishwashers - pump out a lot of humidity), and laundry. if your home has a central AC, than it will remove most of the humidity during the summer months. A whole house dehumidify is primary used during the cooler seasons when the Central AC system is not running.

[@Furiends]

The system seems best applied to mini-splits or radiators. Plus in my opinion the problem solved by combining these systems in the video mostly applies to the calmer of the coastal climates. If the coastal climates were more extreme then it'd probably work the AC more and the humidity would be taken care of. In the more temperate areas of the world forced air tends to be king. For managing humidity it might make more sense to consider variable refrigerant flow as that would be better suited to controlling the humidity as it swings back and forth between seasons. Of course if you have a lot of money there's nothing wrong with having full humidification and dehumidification systems.

[@superspeeder]

Great to see the building pros preaching ERVs over HRVs! ERVs were misunderstood for a long time, and most people in most places will benefit from an ERV over an HRV. In a nutshell, any time the outdoor air's moisture content is greater than or lesser than the moisture content of the indoor air being exhausted, an ERV will temper the moisture content of the incoming air so it has less of a negative impact on your indoor humidity (compared to an HRV which just brings in the outdoor air as-is). AN ERV IS NOT A DEHUMIDIFIER, but it will slightly dehumidify the incoming air during hot humid months, which means less moisture indoors and lower humidity/higher comfort. It will also HUMIDIFY the incoming air during cold dry months and will result in less drying of indoor air compared to an HRV. As Matt points out, there are cases where supplemental dehumidification will also be necessary, especially during periods of high outdoor humidity and low AC demand since the AC just won't run often enough to maintain low moisture levels indoors.

[@tweake7175]

the way i see it is an ERV tries to maintain the moisture level in the home. as simple as that. so your really relying on other methods to dry the home or humidify the home to your required level. you also have to be aware of what happens when you have equipment failure. ie aircon failure. if there is no drying going on, indoor humidity goes up due to people in the home, and the ERV is keeping that moisture in the home.

[@superspeeder]

Exactly, great way of looking at it. In the failed AC scenario, assuming it's hot and humid outside an HRV (or exhaust fan only) would increase the humidity in your house more than an ERV would, so the ERV is still the best choice.

[@tweake7175]

@@superspeeder an HRV would increase the indoor humidity to outdoor levels. yuk but not bad. an ERV would in theory allow it to go past outdoor levels if there is a moisture source in the house like people which could be bad. not to sure exactly how that would work in practice but failure modes is something to consider. here we have 80% average humidity but most use HRV because most homes do not have other means to dehumidify and they use the HRV to keep moisture levels below mold level.

[@superspeeder]

You have to consider the actual moisture content of the air, which is why talking "dewpoint" is better than talking "relative humidity". On a hot day it might be 90F and 60% RH, which is a dewpoint of 75F, which means if you cool that air to 75F it reaches 100% RH (saturation). So when you bring that air into your house through an HRV you're essentially bringing in air that's saturated with moisture. Not good. If instead you have an ERV that's 50% efficient at moisture transfer and your exhaust air is 75F @ 55% RH (dewpoint 57F), the incoming air will end up with a dewpoint halfway between the incoming and outgoing air, or 66F. If you consider the starting temperature of the outdoor air at 90F, the ERV has now dropped the RH of that air from 60% to 45% (dropped the dewpoint from 75F to 66F). Even in the no AC scenario, the ERV still wins as long as the dewpoint of the outside air is higher than the dewpoint of the inside air. On hot humid summer days, most houses would be close to 100% relative humidity inside before that would happen (unless it was really hot inside). In a hot DRY climate where outdoor air has extremely low dewpoints, you may find an HRV would help to keep the interior more dry than an ERV would. :)

[@tweake7175]

@@superspeeder yes, but it depends. having high humidity air come into the house that is air con and is drier, is not a problem. the amount of air flow is not huge and it simply increases the indoor humidity a bit which aircon deals with. problems can come in where the house is cold but still very humid. eg using an oversized aircon that doesn't dry the air. with no AC the issue is not just dew points, its moisture coming into the home from other sources. ERV tries to maintain whatever the humidity level is in the home. HRV tries to equal inside to outside, which is usefull in keeping humidity down to outdoor levels when there is no moisture control in the house. but it works against you when you do have moisture control. i think its a case of one or the other. you either control the moisture in the home and use an ERV to make that efficient, or you don't control moisture and use an HRV. the catch22 is having moisture removal fail with an ERV can cause problems, while HRV is not efficient when you use moisture removal. this of course will vary depending on climate. imho the systems need to work together and be controlled somehow so if moisture control fails the ERV can be switched over to an HRV. at the moment afaik you have to do that manually, i know some people swap out the cores when required.

[@imatl1755]

I'm in the design phase for a new, tightly sealed house in Atlanta, GA (hot, humid climate). We plan to use the same combination of ERV and whole house dehumidifier that you discuss. My question is about ducting. I would guess the gold standard method would be to duct both systems independently. But how well would it work to use a dedicated return line for the dehumidifier but then duct the supply into the ERV supply line (somewhere after the ERV unit). I know there might be static pressure problems if both units run at the same time, but could you set it up so the dehumidifier turning on turned off the ERV? Would you be able to run the dehumidifier long enough to deal with the humid Atlanta air while still allowing the ERV to run enough per hour to bring in sufficient fresh air? Thanks Matt! Great topic!

[@KJSvitko]

Many homes have just too much air leakage. All new homes and all remodels need to have a blower door test and seal up air leaks first. I wish all builders / remodelers did blower door tests as standard practice. It makes the home more comfortable and saves energy / utility bills on heating and cooling.

[@augustreil]

Pretty much a standard here in Ct, at least the homes we work on.

[@StevePatak]

Depending on your local code adoption, BDT is required under the Energy Code. Of course that means nothing if you have a lax enforcement agency doing the CofO on new and rebuilt homes that only requires seeing a certified test document...ask me how I know...

[@HistoricHomePlans]

If you haven't seen Matt's other videos he has done many on how to make homes airtight. Some of them also show blower door tests.

[@Furiends]

@@nathandean1687 You would think cookie cutter homes would be BETTER sealed since they can design in practices that keep everything tight. There's also various ways to build a bank of homes with just a nice amount of variety to make them charming. This sounds kind of weird but the problem here is that they just don't need to so they don't. Its slightly more complicated but it all stems from that. There's a lot of different points where good design or best practice just doesn't get you anywhere even if the cost isn't that significant to the builder. Ultimately any cost to the builder or contractor is a risk so they avoid it. You can't do change orders with the average home buyer either and the bank doesn't care you have an energy efficient HVAC when you get your mortgage. The us gov and state governments do a much better job at encouraging better practice and better appliances. But that doesn't entirely help from the perspective of the builder that needs money to do a good job. Thats why you get things like roofers doing "repairs" when they should be doing replacements as those are better investments in the long run.

[@chuckchrystak4397]

We just built a house and did a handful ourselves including the air sealing. I put so much detail to not miss anything and got our 3600sg’+ ranch with 10’ ceilings in main and an unfinished basement. Got the house to 1.30 ACH. We live in Nebraska so we can see everything from cold and dry and dry to high and humid. I am stuck on what to do. We also have Geothermal, with gas auxiliary heat. My goal with building was to not ever use the auxiliary heat except for if we lost power.

[@certificationtv]

The prerequisite before using the product is that no outside air enters the room. Air gaps in windows and front doors can change the efficiency of the product.

[@richcoyne2141]

I've been waiting for this info for years ..thanx

[@eliinthewolverinestate6729]

I may need all 3. But need hrv on my "vent to daylight" and erv because large planter in passive solar cottage. And may need to pull more moisture out of the air. And with the timber frame and masonry north wall and floor. I want the wood to dry properly over time. Plus will have masonry stove/white oven and heater. Which will need to make pit for hrv near intakes for masonry appliances. Slope floor slightly to allow cold air move that way too. On border of I.E.C.C. zone 6/7 great lakes.

[@nickg3794]

Seen this on This Old House the other day. Now on the dehumidifier, creating dew...in a dark, cool place.... sounds like another great place for mold to grow.

[@psanta33]

If you want to install an ERV into an existing house, and you don’t want the furnace blower to run all the time, what can you do? Can you take the stale air from the furnace return ducting, and then cut a hole in the floor to add a new vent or 2 for the fresh air to get back into the house? I have a single story rancher with an unfinished basement.

[@stevelinder7975]

Great timing as usual! I’m looking at putting in 2 ERV’s and was thinking about a dehumidifier (for the summers) and humidifier for the super-dry winter days (here in Pacific Northwest). Here’s the question: We’re also installing a 60” range with a hood/vent in the kitchen and we’re needing a makeup air system in the kitchen. We’re thinking about having the MU air come out from under cabinetry across from the hood to create a type of air curtain. How do (or would) we tie that cooking makeup air system in with our ERV’s and (de)humidifiers? Thanks and I look forward to seeing ya at IBS in a few weeks!

[@guytech7310]

If you have central AC than you need the dehumidifier for the cooler seasons (Fall, winter, & spring). In the Summer your AC system will be removing excess humidity, but in the cooler seasons your AC system is off, so that's when the House dehumidifier kicks in. I suppose if you live in an extremely humid region (Florida) you might need to run both on those really humid days.

[@jmart21]

Look into the company Fantech. They have a product that is a make up air unit.

[@TheLeaversFamily]

I have a similar idea to yours. I'm going to have the makeup air system come up through the cabinet under the range to create an air curtain over the range to the downdraft exhaust. I'm planning on making a heat exchanger (pipe within a pipe) to help warm the incoming makeup air. This system will be completely separate from the HRV system we will have.

[@keltonlowry8844]

Overall a pretty good video. Some really good information if homeowners are looking. You just are incorrect when you start talking about the refrigerant cycle. Outdoor units do not make refrigerant cold. Also you should use the term refrigerant and not Freon. Being you’re talking about D humidification obviously the unit would be running in the air condition mode. The line that you feel that is cooler is actually coming back from the indoor unit. Technically you cannot make cold you can only remove heat. The sub cooled liquid refrigerant hits the metering device at the indoor unit causing it to flash off and change state to a vapor. After leaving the metering device it’s now 80% vapor 20% liquid. The air moving across the indoor coil causes the rest of the refrigerant to flash off and now becomes a superheated vapor by absorbing heat from the air. The cool line that you are feeling by hand coming back to the outdoor unit technically is what is holding the heat from inside your house.

[@funnlivinit]

Interesting that you should mention Virginia. My Brother lives just outside of Washington D.C. Yes, it is very hot and humid (65-95%) during the summer months, but the heat pump runs almost constantly and therefore can keep the humidity at around 40-50%. The bigger problem is the cold, dry winter months when the Humidity is in the single digits. He's had to install a Humidifier to compensate. Could an ERV help to INCREASE the Humidity as well?

[@tweake7175]

yes. an ERV basically tries to keep the humidity level in the home the same. if out going air is humid and incoming air is dry, then it will recirculate some of the moisture back into the house. keep in mind efficiency levels, nothings perfect. downside is if moisture is high in the house from human sources, then the erv will not dry the house. if you run an ERV all moisture management needs to be done by other means. hence a dehumidifier or humidifier.

[@scorpio6587]

This is perfect, as I am trying to decide this very detail.

[@neckofthewoods24]

So it sounds like I need a ERV and a dehumidifier. I live in middle Ohio so hot humid summers, cold dry winters. I have a ICF house so blower door score should surpass Passivhaus numbers! I’m going to need fresh air pumped in like a ERV but I’ll need to dehumidify in the summer it sounds like. Not sure about getting humid air into the house during the winter.

[@samplumbe3288]

I have installed hundreds of what we call a mechanical ventilation heat recovery unit (MVHR) here in the uk. In flats mostly and about to do houses. I have retro fitted two into my own properties and saved a load of money on Heating bills. They pay for themselves in a little over a year. They also have a condensate Drain and humidity sensors. Great bits of kit. I installed a vent axia unit in a flat and a Nuaire one in a barn conversion.

[@saqaryahmadi1671]

What capacity would recommend for 6500 ft house, with 10 ft ceiling? I had different opinions from different dealers!

[@ericvanzeyl4483]

Building a 3000 sq ft pole barn in Taylor. Was going to just drop in an ERV, but now you are saying it might be better to have both. And with the second unit, close off the fresh air as the ERV is bringing it in? Is there a way you can show a drawing or something on what exactly you are referring? I was going to use the ERV to pull the moisture from both bathrooms and the kitchen only and bring fresh air into the theater, living, and both bedrooms. Any input is great Matt.

[@DubReed00]

Eric van zeyl good question and you were reading my mind. Good luck with your build and I’m interested in how the 2 connect together as well.

[@guytech7310]

Your on the right track. You pull air from the moist areas and push the fresh air into the living space rooms. That said, I would recommend that you exhaust your bathroom fans separately, so the very very humid air after a shower does not pass through the ERV, because the incoming fresh air will be very humid as the ERV exchanges humidity between the incoming fresh & exhaust air streams. For my home I don't pull from the kitchen. I push the fresh are into the AC Duct system which exits into the Kitchen, living room & other rooms. I just pull & exhaust from the bathrooms. That said depending on your layout of your home, you might need to pull from another location beside your bathroom(s). Your best bet would to get an HVAC design engineer to assist you with the ERV\dehumidication system. The Engineer with provide a design that will work right, and safe a bundle of grief & money.

[@ericvanzeyl4483]

@@guytech7310 I have vents set up to exhaust each bathroom but not kitchen. I was going to tie in the kitchen with the bathrooms through the EVR. But if you suggest not doing the bath thru it, would just doing the kitchen stove be ok, and maybe theater and living spaces. Still in the outer shell stage, and have vents already installed to the outside. I have 2 vents set for EVR only, 3 for bath exhaust, and one extra to exhaust heat from my equipment room. I have learned a lot from the experts so any advice I do appreciate.

[@ericvanzeyl4483]

@@guytech7310 one other thing, not doing central AC. Sticking with mini split ceiling cassettes

[@guytech7310]

@@ericvanzeyl4483 You still need duct work for the ERV. Plus a lot of mini splits can get costly. You can go with ducted mini-splits to service multiple rooms.

[@davesavage3579]

Matt, you and none of the comments below mention all of the dehumidification water being pumped outside the hose, next to the foundation. In Atlanta our small system of 1,400 sf pumps out 3-5 gallons a day. I drain it into a 55 gallon barrel and regularly lug 5 gallon pails of water to my dry garden areas. I'd like to here what you and others do with this flow. Maybe most just run the water line to a drain.

[@cliffordbradford8910]

That's good deionized water. It's good for washing your hair especially if you have light colored hair

[@modestkornilov7320]

Hello from Russia. I impressed, that you compare this type of recuperator and dehum. There are different types of recuperator: aluminium or special plastic. These types of recuperator more effective! In Europe we successful used them for swimming pools.

[@waltergartner4538]

Matt, I see Ultra-Aire offers ventilating dehumidifiers (I'm looking at the XT155H). Would there be any reason to use an ERV if you configured the XT155H to provide ventilation?

[@Furiends]

I feel like "dry" is a relative thing. I lived in a house that got so dry my lips would just start cracking. It's really 45-50% thats comfortable. The probably is humidity is really a problem as temperature changes which is why really forced air systems should have dehumidifiers on them. Whereas on a high performance house with plenty of insulation and slowly changing temps managing the humidity is doable in other ways including just venting with an ERV. I question the idea that simply high humidity outside would cause an HRV to go airy at least as a general rule. Even if you lived in a coastal area where you can get up to 65% humidity only a fraction of that gets through the ERV. The problem therefor is that the HVAC is actually just not providing any dehumidification in a lot of circumstances and thats a design problem with the HVAC. if the HVAC is suppose to be a high velocity system that only runs for 30-40 mins a day now you have another problem with an uncomfortable forced air system that blasts hot or cold air at you and no dehumidification.

[@donalda777]

Hi Matt, Love the channel!......just a suggestion...replace the word “suck” with “draw” 🤠. Thanks for explaining air exchange/dehum. We will be installing in our next house.

[@andyreimers9834]

This is an older video, but we are currently choking on wildfire smoke in California. This seems to be an annual thing for us. Would love to see how to design for, then use, modern home HVAC systems when outside air is horrible. Thanks!

[@jamespatrick5930]

Matt, I have watched many of your helpful videos over the years & really appreciate how you helped me design & build my energy efficient retirement house that includes a HRV. Your use of the word mixing is off the mark, you could use exchanging. Then 2x times you said that the dehumidifier brings in fresh air.

[@UltraAireDehumid]

James - ventilating whole house dehumidifiers can bring in fresh air. Our units provide supply ventilation with a MERV 13 filter, which is typically recommended in humid climates if the home is not super tight. The ventilation can be set up on to run on a timer based strategy.

[@djbutch123]

What is your reasoning for wanting to keep the house pressure neutral? In most commercial cases we keep them slightly positive. The thinking is that it's better to spend a little extra energy to pressurize than to have neutral or negative pressure and have intrusion. Therefore most ERVs are sized to exhaust less than they supply. I would think that this same thinking would apply to a house.

[@nordlands8798]

Exhausting (out of the house) more than supplying (into the house) would give negative pressure.

[@djbutch123]

@@nordlands8798 Oops! good catch

[@nordlands8798]

At 1:26 you say the ERV sends the outside air out again (wrong) after passing through the core, then at 2:11 you say it goes into the house (correct) after passing the core.

[@hj8607]

These unit are adequate for low CFM exhausts as in a bathroom BUT a gas range needs a exhaust hood using 400-900 CFM (or more) by code . You will need to have a independent air replacement ducting in place with a active air flap to replace that much air. IF THIS air comes into the home very close to the range the Hood will actually work . (no high volume air replacement results in Minimal air movement in hood exhaust and code violation.)

[@beachboardfan9544]

Why wouldnt you want your home positively pressurized? That seems like the ideal scenario, especially for allergy sufferers or people that live is areas of poor air quality.

[@charleswhalen7332]

Matt, how many minutes per hour (or equivalently, what percentage of the time, or cumulative hours per day) does your Ultra-Aire 120H dehumidifier run during the spring and fall seasons in your new 2800 sq.ft. house there in Austin? Btw, love your channel and vids, learning a lot from them in planning the build of my future zero-energy solar home. I’m trying to understand what the energy consumption of these ERVs and dehumidifiers is. In another video, you said that your new Zehnder ComfoAir Q600 ERV consumes around 100-125 Watts continuously, 24x7. So that’s around 2.4 to 3 kWh per day. Here in this video, you said that the Ultra-Aire dehumidifiers consume between 5 and 8 Amps when they’re running (so that’s 600 to 960 Watts), but you didn’t say what percentage of the time they typically run (e.g., in your case, specifically, during the spring and fall seasons there in Austin, when they would be most needed and heavily used). Hence my question above. If your Ultra-Aire 120H dehumidifier runs 50% of the time (30 minutes per hour, or 12 hours cumulatively per day), that’s 7.2 to 11.5 kWh per day. If it runs a third of the time (20 minutes per hour, or 8 hours cumulatively per day), that’s 4.8 to 7.7 kWh per day. Even running only a third of the time, that’s still a heck of a lot of energy consumption for a solar-powered home trying to achieve zero net energy. Thoughts or comment? Thanks!

[@NickShoust]

I feel like in northern climates an air exchange would be great. 90°F+ during the day and sometimes only 40s over night you could cycle out the warm stale air in the house and bring in the cool fresh air through the evening

[@adriano_suella]

Hi Matt, very interesting comparison! We just finish to build our home here in Europe, Mediterranean aerea, not so cold but quite warm and humid in summer. We installed a combi machine that does HRV + heating through the ventilation and onboard heat pump + domestic Hot Water. To solve the problem of the air humidity and A/C functionality we installed an indoor coil connected to another external airconditioning heat pump. This indoor coil is installed just before the supply collector and works independetly from the combi machine. What do you think about the combi machines in general for the modern high energy efficency homes?

[@johans7119]

Our MEP said we don't need a dehumidifier in Houston. New build with Conditioned attic, VRV, R-38 spray foam on underside of zip roof deck. Felt and Shingle roof...

[@buildshow]

In my opinion he’s wrong. I’d put a Dehumidifier in every new home in Houston that I’d build.

[@johans7119]

Matt Risinger - Thanks. He said the "VRV will handle humidity year round. No dehumidification is needed in winter. The only time it's not running is when all set points are met." My understanding was that the cold winter air just can't hold humidity. There's a particular graph MEPs use for this. Any thoughts?

[@BrianBriCurInTheOC]

D B You are comparing Apples to Oranges in that statement.

[@johans7119]

William Durham This is why we selected a VRV, it can operate under partial load meaning its not cycling on and off and failing to dehumidify. However we know people in South Florida who use ERVs with a conventional split system. I'm keen to know why @Matt Risinger thinks we'd still need the dehumidification.

[@samel986]

@D B Hello. I'm going to be building my family home this year, if possible I would like your personal opinion on a system to install in a 2400sf home in south west Florida that will take care of eveything in one unit?. What digital thermostat would you recommend that can control multiple zones via dampers in different parts of the house?

[@virgil3241]

Ive learned in the last couple years of research, and my recent HRV installation is this. No matter which one you pick, its wrong. Even if you pick the correct one for your ZONE, others will argue with you until they are blue in the face that what you selected was wrong.

[@joebeauchemin]

Recommend a unit that has enough cfm to also work as a good bathroom fan on high?

[@buildshow]

Most ERVs have a low/high boost for bath fan action. That Trane model on the desk with me has that capability.

[@BrianBriCurInTheOC]

Matt Risinger Thank You Matt for KNOWING these products and real Building Science! Guys in the Trades and Builders can trust you to not just Sell a product, but Teach us guys in the business!!!

[@allent555]

So this would replace the bathroom fans ?

[@davidgagnon2849]

@@allent555 I hope not. I think that would mean everyone in the house gets to experience your latest dump.

[@daltonmorrison5193]

@@allent555 Yes the most efficient use of a HRV is to have it replace all the bathroom fans in your house. It essentially becomes your bathroom fans and your principal exhaust system all in one. However it is important to note if you use HRV to replace bath fans it must be sized properly to handle not only Principal building exhaust but bathroom ventilation also.

[@rapfreak7797]

3 year old build in Ohio, relatively tight build but builder just has a bathroom exhaust fan running 24/7. Can you recommend an ERV that would be good for a retrofit application? Do you recommend having an HVAC contractor install or good for an experienced DIYer?

[@jeremylourie5270]

These look simple, but there are air distribution and load issues to consider here. I recommend an experienced HVAC installer, preferably one that comes with a personal recommendation.

[@guytech7310]

Cannot be that tight if the bathroom fan runs all of the time since it has to be pulling air from leaky sources. if you want to go the DIY Route, find an HVAC engineer to design the system for you & then do the install work yourself. a HVAC engineer will have the experience to get you a proper design.

[@daltonmorrison5193]

Design is very important but equally important is balancing the unit. If the air is not properly balanced it is useless. So I recomend professional installation.

[@alfredotan6136]

I live in a country where relative humidity ranges from 51% to 97% and the temperature ranges from 24 degrees Celsius (75 F) to 35 degrees Celsius (95 F). May I use an ERV but invert the intake and exhaust?

[@rromero2924]

If you lived in an underground concrete bunker where you need to control the humidity inside more than anything else, how would you insulate and control your air quality inside? Would you use an erv and a dehumidifier? Does the dehumidifier only dehumidifier the outside air?

[@draggingcrewcab]

Another great build Matt!!! Should Central Texas new Homes also have a humidifier such as the Aprilair 800?

[@jeremylourie5270]

Most of Texas is humid enough to warrant a dehum. They are more important for comfort and energy efficiency of the home than an HRV/ERV, because lower humidity let's you feel comfortable at a higher temperature. In Texas, this ballace can actually save money. Have a qualified HVAC contractor run some load and cost calculations to see what your best options are in your area.

[@jeremylourie5270]

Matt, Why would the close the dehum incoming air instead of running all of the ERV thru it? Is there any advantage to keeping these units seperate?

[@guytech7310]

Probably depends on how much humidity your region has. If you live in humid region probably the #1 source of humidity is from the outdoors (ERV). So dehumidify the fresh air is probably the best option. If the #1 source of humidity is from indoor sources (indoor hottube, souna) then it probably wise to cycle your indoor air. Issue is that your trying to control humidity with the least mount of energy needed. Also some older, leaky homes may to be retrofitted to include a whole house dehumidification system. Unless you can seal the home up tight adding a ERV isn't going to prevent humidity from leaking in.

[@Furiends]

It wouldn't be balanced if you did that. You can only damper the dehumidifier. So you could feed through it if you used a balanced diverter but then whats the point?

[@UltraAireDehumid]

We typically recommend keeping the systems separate but you can integrate the two. Here is an article we wrote for Green Building Advisor on how to properly combine the two systems www.greenbuildingadvisor.com/article/ductwork-ervs-dehumidifiers-forced-air-heating-systems . Hope this helps!

[@josephhuether9572]

I though -- perhaps incorrectly - that Austin was relatively dry. 40 - 60 RH actually sounds sort-of high to me. When I think of art museums I think 45 RH. In the northeast, if you step into a museum during heating season you can really feel the increased humidity. In the northeast, your AC does a good job of dehumidifying except in homes like mine where occupants are constantly opening and closing doors to let dogs in and out or leaving bedroom windows cracked at night. During the heating season we are left craving a bit more humidity.

[@kimkennedy9640]

I have (2) 70 pint store bought dehumidifiers. They are pulling 250+ pints most days from my 2k sq home. They both are running now and it's 62% humidity in here. It would be in the 80's if they weren't running. I have a pool that gets ground water behind the liner. I'm being told due from the lake the property is on. Im guessing those issues are contributing to the humidity in the house?? Does it sound like I have more issues than what a whole house dehumidifier can fix??

[@Will_Wel]

Great video. Anyway you could do a comparison between brands of dehumidifiers such as Ultra air, ideal air, quest, anden etc.

[@bannockchief]

I'd like to see how effective the thermal bridge is. How much does the temp of the incoming air change; 5°, 10°, 20°?

[@FreekHoekstra]

It seems good erv’s extract up to about 70%

[@mikemcmanaman7634]

Very informative, specially if your in a humid climate. The drier states were not addressed though. There are many states that don't have the humidity issues you were talking about. I.E. Idaho, Nevada, Arizona, New Mexico, Wyoming, Montana, Eastern Washington and Oregon And 3/4 of California, basically states west of the Rockies. The ERV seems like the unit of choice, would like a more detailed evaluation on that.

[@aannddrreeww1000]

I dont know much about the difference between hrv and erv, but Matt emphasizes that dryness in a house keeps fungal growth down and generally keeps your house from rotting and mold. While this seems to be true, is it not also true that ADDING moisture to your home's air helps to keep a home warm? I heard somewhere that in cold climates like Canada, where I happen to live, adding moisture allows the heat to be more effectively distributed around the house compared to a dry house. Thus, your furnace doesn't run as long to keep the house at the same temperature as a dry house. Is this correct?

[@weekendwarrior9171]

yup. In Canada I doubt you would ever have to worry a bout too much humidity though.

[@giocondobianchi6557]

Matt can you do a review of Tesla glass roof titles please. You would be one of this first to review this product, very innovative !

[@Karjis]

Oh the ERV model looks like the 90's air exhange units nordics have used with this "box shaped" crossflow heat exchanger where air streams are only roughly 50% efficiently transferring the heat. Modern units have long counterflow air exchangers to get the efficiency up to 80-90%. My 20 year old unit is basically just what there is on the left and it was the cheapest option to satisfy fresh air requirements (here it is 1/2 of the house volume every hour) but the energy efficiency is.. well not the best. But yes it has balanced airflows and it recovers some heat / (cool during summer) to fresh air but only roughly the half as the box shaped heat exchanger is .. well cheap.

[@zacharyfrench3311]

What about a state of Michigan? We have literally the worst humid summers and spring but our winters can get cold

[@Zorlig]

I know it is sponsored but I love this type of episode

[@brianroberts9984]

Question about installing these units. I agree in the warm-humid areas (I am in North Carolina) we need both units in a house. I have ductless minisplit heat pumps (7 IDUs, 2 ODUs) and 2 ERVs in my new house, but the humidity gets too high. However, I have been racking my brain trying to figure out how to integrate the two. My ERVs have dedicated ductwork, which I want to use for the dehumidifier I need to add. I guess I will need to add 4 new electronic dampers to plumb into the existing ductwork? But then, how do I deal with the controls? My ERV controls read humidity. If the ERV is on a 20 minute per hour cycle, can I wire the dehumidifier into the ERV outputs to open the dampers and power on the dehumidifier for the other 40 minutes? Also, why are all the whole house dehumidifiers 8" connections? Most ERVs seem to be 6"?

[@stevepailet8258]

seems like the best place to exhaust the dehumidified air would be in the utility room with the hp water heater Then you could use the warmed air.and dump out cool air to the rest of the house

[@lightdark00]

Doesn't work for houses where the water heater access is from the garage. The warmest thing here that's always on is the refrigerator.

[@dh66]

Lol yea no. Go draw out the ducting for that

[@stevepailet8258]

@@lightdark00 if the house is in zone 1-4 it likely is warm enough to put the hp style water heater in a garage. I would not picture lots of water heaters in a open garage in colder locations though perhaps you know more than I do about living in cold locations and putting a water heater in the garage

[@taforth]

👌 perfect topic. Thanks I was just trying to decide what’s the best approach for my cottage, that has a 3 seasons building permit, but is used regularly in the winter as well. We have hydronic in-floor heating in 3” slab floors throughout, so the heating system doesn’t dry the place out at all in the winter. Window condensation is an annoying issue, especially with wooden interior window frames, along with drywall returns 🙄. I had an HRV pretty much from the outset, but it doesn’t seem to do that great a job once the humidity level starts getting down around 40%. Recently, I purchased a whole-home dehumidifier, and it also doesn’t seem to take that much water out of the air at the lower humidity levels either…

[@UltraAireDehumid]

Terry - please reach out to our customer service department to discuss your dehumidifier install, or email me at [e-mail]. We have seen some issues with the actual install that minimize the effectiveness of the dehumidifier (no matter what brand you have.)

[@PentaxBlogger]

You are a BIG fan of FANS :)

[@windyway2424]

Wow, interesting to see an objective perspective to these devices. I live in Europe, Germany and it`s horrible here. By law, all new houses have to be built with HRV, even if you dont need it. We dont have something like a ERV here. Additionally if you dont live at the coast, you will have at least 2-3 months of summer with +35°C degrees and huminidity sometimes is high, with 60-70%. And you just dont have devices to cool the air and get the humidity out. You are not allowed to built your home with A/C, if you do, you will get problems. And to be honest, I dont know if a dehumidifier would be allowed, but I have never seen a home which has one and have not even heard of that possibility here. Next problem here is, the HRVs are built that way, that you cannot turn them off. So it has to run 24/7, 365 days of the year. As a result in summer, you get the hot air blown into your house. And you are not able to get it out. Of course you can open your windows at night, but nights sometimes have 23-24°C, its typical windless in summers here (if you dont live at the coast) , and if your house has 29/30, it may cool down at 25/26 during the night, but it`s impossible to make it any cooler than that. And it won`t last long, because the HRV will start blowing hot air into your house as soon as the sun heats up the air. And of course, additionally you are not able to get humidity out too. I really hate politics here. It`s just a green bubble without any logical thinking and arguments. Because in case you dont live in the mountains, the winters don`t even get that cold. There are regions where it has not snown in the last 5 years. And many may have snow, but only on 5-10 days of the year. The majority of the other winter days will have something between 5-10°C. But they argue because of heat loss in the maybe 30 winter days, where you heat a bit more, you must install HRV. And as a result you have at least 60-90 horrible hot days in the summer just because you have to install HRV, which has to run every day, cant be turned off and you are not allowed to use A/C (and dehumidifier probably too). It just sucks to live here.

[@markthomasson5077]

In the summer you describe, the HRV will cool the air, if it is hotter outside than inside. It will also remove some humidity, hence the condensation drain. So that is much better than bringing in the same amount of external air, which is hotter and more moist. You should be able to run the system on low during the day, maybe higher at night. Here in UK, most systems have a summer bypass function. Can you not buy stand alone dehumidifiers, we have one, works very well, though a bit noisy.

[@JulioCSolar]

Thank you for sharing. Can you specify both maker and model? Also, how about space pressure diferential?

[@rromero2924]

Can you explain better HOW these work together? Do you disable the motor in one of them so the motors aren’t fighting each other? In what sequence do you connect the ultra aire and erv? Indoor air, to dehumidifier, to erv Indoor air, to erv, to dehumidifier Or some other sequence?

[@Archibald82]

1966 Bungalow 1200 sq ft 2x4 Construction + ext rigid foam ACH of 1.9 Double pane windows No HRV or ERV Heated with 18,000 BTU LG Ductless Split Family of four Condensation issues on the windows attempting to be rectified with an Energy Star stand alone dehumidifier in the basement. Even with humidity

[@nationsnumber1chump]

I have a humidifier with a manual dial. Had to buy a humidity meter to make sure what I set it at is the typical %. System is 10+ years old. Great video. Things to consider when I upgrade soon.

[@eaglecot]

Thanks for the video, Here in Sweden the outdoor air quality is good enough that filtering the air isn't really needed. So I stumpled upon decentralized ventilation with ceramic stones that claim to recover 90% of the heat and 20% of humidity. The idea is so clever. It wouldn't be my first choice since you can probably hear the fans in each room. But I would love to see a video about this. Unfortunately it's not really an option where you need to cool and/or filter the incoming air, I suppose.

[@belg4mit]

The goal of these is not to filter the air. They have an air filter, simply because they can be pulling in a large volume of outside air and need to protect the equipment from dust and grit, but their function is in their name.

[@markthomasson5077]

Depends on the trees. Pine is good. Birch is bad, due to pollen induced asthma

[@keithhogan6997]

What type of energy load do these units put out? I'm looking at being 'off grid' and need to take this into serious consideration. I live in Oregon, the PNW ... Pacific North We(s)t. I've been watching a plethora of your videos and am already looking at ICF, Zip R sheathing, amongst others. I would like to keep the humidity down as well as my energy expenditure. Hopefully soon all of these components will come to fruition with my own build. Thank you for sharing the wealth of information!

[@BorisFett]

I really like your videos. I always seem to miss out a bit because i'm in a different climate than you. Northern Oregon. Im buying a 1940's home and making a list of all the things i want to change in it. Looks like an ERV is going on the list alongside a new furnace.

[@terrencesauve]

Dont forget the blower door test first! Its impressive how some little improvements can change the sealing of the house and increase the comfort.

[@fatdiesel44]

Great explanation, thanks Matt!

[@robbiewahl9860]

I love the videos but I think there are a couple of things in this one you may want to clarify: 1. Dehumidification occurs at lower temperatures because air can hold less water because molecules are closer together. The air coming out of a dehumidifier is only warmer because the system uses the cold air to off-set the heat load generated by the small compressor which re-heats the dehumidified air. Otherwise the unit would add heat load to the building and the air exiting would be cold. (Unless using an desiccant wheel which is another ballgame.) I have to explain to owners constantly that warmer air is NOT dryer air because they think the warmer it is the more desert-like the environment. 2. You seem to be saying that some homes rely on negatively pressuring a house to draw in fresh air (though you do mention balancing later into the video). For those thinking about installing a fan: Not only is that a really bad idea from a rot perspective but it’s also a less than accurate or controlled method for this. HVAC code allows for windows and doors to count for some outside air via leakage around openable items (where they meet stops and thresholds) and some via the opening and closing of the doors and windows BUT never through a sealed vapor barrier or other areas. The amount via doors and windows often accounts for all the code requires for outside air in a home BUT throwing in a fan pulling it in is not an advisable method unless you’re using a tempering system like the two mentioned in this video AND / OR you have balanced the building properly (with a very slight positive pressure) with the fan installed.

[@tweake7175]

positive or negative pressure depends on climate your in. if its really cold positive pressure can mean frost build up where moist indoor air exists the house. those places like to run negative pressure to avoid that. in warmer climates positive pressure is better. however i suspect what hes referring to is builders doing it the cheapest nastiest way possible (assuming its to pass code), with no care what so ever on the long term effect on the house.

[@tweake7175]

@Bill Williams unfortunately here most home owners do the same.

[@alexgray1905]

Very interesting and very informative ... great job explaining what I consider difficult thermodynamic concepts. 👍

[@ahowl7mx]

Crazy question, when can we see a window unit version?

[@pcfabris]

Love the dry heat.

[@mattv5281]

Checking in from Colorado... My house is currently at 10% humidity.

[@jlanemiller]

Matt V yes I’m in Longmont and I’ve started monitoring humidity levels to regulate some hardwood floor movement (as well as simple curiosity) it’s very low humidity, even running a couple of room humidifiers and it doesn’t get past 35% after running all day

[@Furiends]

yup. I know matt is doing a sponsored video and in his experience this is at least a real solution to a real problem. But I do think overall this is more of a corner case across the country. You have to be in that Goldilocks zone where its temperate enough to need a big AC but also humid and airy enough to be humid a lot outside. Frankly it seems like it'd be better to avoid this kind of system in those situations.

[@gobofraggel7383]

I have chronic debilitating Asthma and it affects me no matter where I go. The only thing that helps is being outdoors. On my honeymoon I slept on the hotel balcony, for my recent vacation I slept on an air mattress in the yard, and I spent a year sleeping in my car. I go to bed and wake up gasping. I need some guidance for getting a system like this in my home which is more like a 4 story building with an apartment on each floor attached on both sides by other homes. I have balconies on the front and back. Was thinking of testing this in a 10x10 room intending to sleep and work there. How can I do it? For now I would be happy with anything that brings in outdoor air and warms it because winter in NY can be brutal. Any ideas?

[@RDhali]

Confused about what would be required in Southern Ontario Canada. We get all 4 seasons... Also have a decent AC system. Erv or hrv?

[@daltonmorrison5193]

I live in Canada also. It depends on on your home and average humidity levels you have. HRV ventilate and recover heat only. ERV ventilate and recover heat and humidity, it recovers the humidity by allowing the air being exhausted from you home to mix with the fresh air being drawn in to your home. In my professional opinion I would install a HRV if you are using it for principal exhaust and bathroom ventilation. If you are only using it for principal exhaust and you live in a dryer climate I would recommend ERV.

[@tombomombodombo]

Both! And a dehumidifier and humidifier too! You can be the mother nature of your house!

[@junado]

I live in south east Quebec and we installed an ERV to actually keep some moisture inside during the winters, it keeps the humidity around 35-40% in winter without adding an humidifier.

[@Furiends]

For a start most everything mentioned in the video doesn't apply to you. Some of the negatives mentioned in the video are positives in temperate climates. You should have an ERV because you want to moderate the humidity not add or subtract it. The cold parts of the year mean its dry outside but humans provide plenty of humidity on their own. The only other issue is when there are major temperature swings as seasons change you don't want those to cause condensation throughout your home. Your best friend there is a well insulated home and smaller HVAC not a poorly insulated home and a large HVAC. If you have for example leaky or poor performance windows that'll cause problems and a way people deal with that is to keep everything super dry. I believe my health is more important though and that the house should be designed around me not the other way around.

[@ericbommer2280]

What if I already have a de-humidifier, would that not be significantly cheaper and do the same as your unit with an ERV, especially with an AC unit to help my dehumidifier.

[@naturalhealing9970]

Can you duct the dehumidifier and ERV together, so first the dehum and then that goes into the ERV?

[@scottwebber652]

I’m in the north n in winter window moisture is an issue. Anything from dew to frost on window panes. Definitely have more with higher humidity n less as it goes down but none the less it’s there. How about some feedback on this.

[@TimMontague]

We'd love to see you cover the CERV2 for intelligent IAQ.

[@paulomontero12]

I have an hrv and in the winter it actually makes my too dry in the at only 20% humidity. I need a separate humidifier most likely?

[@nedunonnyp704]

When Exhausting/Supplying from/to more than One Area/Room/Locations, How do you maintain Suction/Supply Air? I notice a Significant drop in Air Suction from Exhaust and Decrease in Supply Air when I "Tee" in to more than One Area. The 6in Ducts drastically drops the air movement after I "Tee" Off into Any Location. How do You Overcome this?

[@jochute]

love the videos. I have posted before but I would love full length "how to" videos in conjunction with the great explanation videos you do. Is there a cheaper way to control the ultra aire dehumidifier than their $250 Ultra-Aire DEH 3000. Seems expensive when adding to the cost of the unit. Thanks

[@KevinLyda]

In radon areas wouldn't a bit of positive pressure from the roof be a good idea?

[@tompaj10]

Do you add exhaust to you bathrooms or stay only with ERV??? With ERV in order to clear up bathroom you will need to ventilate rest of the house quite vigorously, so I am quite confused ...

[@weekendwarrior9171]

I believe on one of his episodes the homeowner made the bathroom vent the erv return. If you are going to need it anyways

[@Sunxfan]

Very good video,what kind of fan ?

[@meowzic]

I remember one of my friends had a little outlet hole in every room to purify air and bring in fresh air. I wonder if this is what they had

[@Expressiton]

Do they make small ERVs for tiny houses? That unit is way too big for my tiny.