Passive House - Fresh Air System Install & Costs (Zehnder)

Hopefully you know the benefits of building a tight home. With a properly sealed envelope we can increase our control over the conditioned space. This control is equally important for the durability of the building, as it is for occupant comfort and health. Because of this, building tight also means we need to ventilate right. Continuous, balanced ventilation is key to maintaining comfort and indoor air quality while reducing our heating or cooling costs. This is done through an ERV or HRV. These units will help extract energy from exhaust air and this energy to precondition fresh air we are supplying back to the house. And we can filter this air, giving us the peace of mind that the air in our house will never be stale or dirty. This is far from the reality of living in a leaky home with many exhaust fans with little to no supply or balanced ventilation. In this video we’ll see why Matt chose to install a Zehnder ERV at his house, what is involved, and why it is probably easier to install than you may think.
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[@iwenyou]

I can upvote for him. In China, even though it is better now due to many efforts, but a lot of family started to installing fresh air systems when renovating due to the bad outdoor air quality. The trend started about 5 years ago, and I think it probably going to become a trend in the US due to wild fires each year... We live in north cal, and we are most definitely going to install one next year.

[@danielrussert1375]

Matt, we start construction on a Passive House in September 2024 in WI. Trying to contact a Zehnder dealer for product and installation. You have a great channel.

[@townsendliving9750]

I'm sold, was basically going to do something similar, but this is the nicest kit I have seen. I'm a mechanic, and complete user friendly kits are the only way to go. I'm not sure I can afford to get the system right away, but I'm going to put it in my plans, and implement it when funds arise

[@grzmil1]

Hi Matt fun fact from Poland. By code, min ventilation rate is 0.5 house volume per hour, however when designing good ventilation, people often recommend 1 house volume per hour. Great channel. I've learned a lot about building from your channel and you got me interested in the topic. Thx 😁

[@robertmccammon9024]

Ballpark prices, I'm so proud of you. Thank you.

[@CompCrasher86]

Ballpark numbers was the difference between “the average homeowner could never afford these high end products” to “hey I’m an average homeowner maybe I could save up towards that”. Gotta change the stigma!

[@markseamans4682]

I’m breaking ground in a month, I like the idea of this. However I bet Matt’s HVAC would cost me over $40k. I need sponsors.

[@jgoody7467]

@@markseamans4682 I will sponsor you.

[@markseamans4682]

@@jgoody7467 haha!

[@steffenpelz7114]

@@markseamans4682 way over $40k. It would likely be $50k+ plus builder P&O and Supervision. So $65-$75k. I spoke to a builder recently who put in a very similar system on a job to this, but this is even higher end.

[@tomtaft5056]

Matt, thank you. About to build my own super tight house, and this i clearly the equipment to use. Glad it was a long video, so we had time to absorb it all.

[@octavianboghici]

Amazing stuff! I appreciate your honesty and openness shown in these videos documenting the "how-to" and the "why" of different technologies implemented into your house. Here in Europe, we also have certified passive houses and even premium passive ones with top energy-saving solutions such as CLT panels used in the assembly of exterior walls, floors, partition walls and roofs walls, passive house doors, passive triple-pane windows with weather-based electrically controlled blinds, wired/wi-fi weather stations with humidity, air pressure and light sensors, green energy from photovoltaic and solar thermal panels, integrated smart meters and KNX-based protocols for remote monitoring and controlling of a variety of appliances such as the geothermal heat pump, ventilation units, room temperature sensors, hydronic systems such as subfloor heating and radiant cooling ceilings, wall-mounted smart switchers and app-based interface for ambient light scenarios, CAT 7/8 structured cabling for connected IoT devices and much much more...there is a growing worldwide tendency to build smart and even energy self-sufficient premium passive residential properties, office buildings, schools, kindergartens and the like....I would love to see some of these smart house solutions integrated into your project. Stay healthy and keep up the good work!

[@kevinmazzocco]

Matt, you nailed it when you brought up wildfire smoke and filtration. Thanks! We're so tired of breathing crap air every summer in CA.

[@TheShallDog]

Please do a video this detailed when you install the heating and cooling system you plan on using!

[@jopo7996]

Great video. It's awesome when the questions you have floating around in your head, are gradually answered throughout the video. So rare for presentations like this.

[@asa_williams]

This reminds me of an episode of this old house with the camera shots and conversation setup

[@robertfeliciano5723]

I was thinking the same. However, TOH would have added a light to the dark attic and had smoother camera movements, I was getting nauseated from the shaking.

[@HectorPerez-tb8hn]

like fake news etc lol

[@jamskatelake]

That’s the point

[@publicmail2]

Top of the line, looks like a great design in that they took everything reasonable into consideration to make a perfect unit. .75w/cfm is very efficient, it has to maintain proper cfm throughout varying SP's. Only $9.50 month at $.13/kwh.

[@nicolascardillo7615]

Just 1 solar panel of 400 Watts can run this system for 10 years or more for free (after the cost of solar panels, Battery, and control system) and still have some extra energy to spare. He said this big system would use about 100 Watts, so about 2,400 Watts a day. The average day is exactly 12 hours, the power you actually get on your panels is equal to about 6 hours of full sun radiation per day. Therefore 1- 400W panel (or 4 - 100W panes for lower price but need more space) would create 400Wx6=2,400W a day. Now, this house has a great large open space for multiple arrays of solar panels systems and since his whole house is running on electricity He can practically run the entire house on solar. He does not even need a battery backup and connects the Panels to his Electric Miters and the power production would be subtracted from his Bill. In some states, if u produce more power than use they would even pay u for the extra energy u give them. Now since he lives in Texas a really hot n sunny state his power production would be even higher, so I would have a backup battery for emergencies since Texas Power System SUCKS! WHY THE F***!!! Texas is the only state in the country that is outside the National Power Grid?

[@nieldcreek2098]

@@nicolascardillo7615 an average day on my planet (called earth) is 24 hrs…

[@robsdeviceunknown]

As someone who lived through 13 broken ribs and 2 collapsed lungs... I can relate. Extra holes SUCK

[@ttvparallelsanti]

In situations like this, it's hard to know if they suck, or if they really blow! 😁

[@JeffandJake]

Using your videos to inspire my build up here in Canada :) thanks for the great FREE videos!

[@boby115]

Looks like a very good system, definitely important on a house built this tight. Would love to see the TAB contractor's ( third-party , must be third party to eliminate any conflicts of interest) results when his house is completed.TAB = testing, adjusting and balancing ( it is an actual trade with certification used mainly in the commercial and industrial building industry). With the covid virus TAB technicians are in very high demand right now, the mechanical engineers for hospitals and school are currently demanding a much higher air turnover rate with more make-up air. Good for my industry ( gas utility), bad for the customer ( higher utility bills). Currently in Germany all schools are mandated to open all windows for 10 to 15 minutes every hour ( they turned the heating system off and open all windows, after 10 or 15 minutes they close the windows and turn the heating system back on for 1 hour and repeat.). I can't wait till this covid virus thing is over.

[@shawncockrell6007]

I liked the little black boxes with facts...very nice touch. Only mis spoke information was on the bedroom co2 sensor, it will not ramp up the bedroom, it ramps the entire system in all rooms as there is no zone flow capabilities. Flawless presentation other than that one mis spoke, covering/touching all the bases.........excellent job, excellent system !

[@christophersmith1894]

Shawn, you are absolutely correct. Thanks. There is no "zoning" on this ERV air distribution system. We did review this together after filming, but the note got missed in the editing.

[@aldoogie824]

Something needs to be mentioned here - for anyone considering installing an ERV in a vented attic - you're going to want to make sure that attic is well ventilated and that ductwork well insulated. Using the regular uninstulated rigid ductwork is going to fine as long as its housed in a conditioned space. All this seems fairly straightforward, but I do feel like it may get missed if an installer or DIY person isn't considering this.

[@GaiaCarney]

Matt Risinger, thanks for sharing this! I appreciate your dedication to clean indoor air. That Gas appliances add the possibility of carbon monoxide is reason ENOUGH to go all electric ⚡️

[@mightyconker3903]

Gas heating is far far cheaper than electric and likely more environmental too depending on the source of your electricity

[@holychitlingravy]

@Matt Risenger: You mentioned no ventilation penetrations, which is good, except for the Kitchen. Kitchen gases don't just include moisture, but hot grease/oils which break-down into esters that act like paint, they can gum up your ERV/HEV exchanger membrane in no time. Unless you have extreme filtering, don't vent anything in the kitchen to your ERV/HEV (or HRV). Just look at the pipe behind your old range hood and you'll get an idea about how ineffective range hood filters are. I don't know about Texas code, but it's probable that just using an HEV or HRV, even at max output to vent kitchen, may violate code. The cases I've seen in California do with following exception: Cooking appliance that is in accordance with UL 710B for reduced emissions where the grease discharge does not exceed 2.9 E-09 ounces per cubic inch (oz/in3) (5.0 E-06 kg/m3) where operated with a total airflow of 500 cubic feet per minute (cfm) (0.236 m3/s). Frankly most home kitchen range hoods don't meet code in California, but this is one of those areas where the inspectors are allowed a lot of leeway. Hope this reaches you in time.

[@populistparty2010]

Thank you for that...good info.

[@DocNo27]

yes - microwave with built in "ventilation" are a joke. I put a real hood in over my cooktop an the difference it makes is amazing. And it's not that big a deal to crack a door to get enough makeup air when it's on high. I probably should have some sort of a make up fan but I'm not staying in this house long term and I certainly won't get the investment back. Having sold houses in the past when moving most people are beyond clueless when it comes to infrastructure - all they care about is move in ready :p

[@christophersmith1894]

Matt is not venting the kitchen hood through the ERV. You're correct...we DON'T do that! ;)

[@Spooms1961]

MATT! You definitely need to check out the heat pump condenser clothes dryer. They are super effective and efficient and DON’T NEED VENTILATION! These help keep the envelope of the house tight and super efficient. Oh, and may I please suggest you purchase a gymbal for the camera. It will negate much of the shaky movements. When I was working on my own documentary programs as a cameraman and editor, I used one for a fashion shoot and it helped the image to stabilise greatly. Cheers from Australia mate. Keep up the good work.

[@buildshow]

Actually I’ve been testing a Miele heat pump dryer and it’s pretty amazing. Perfectly dry clothes. 45 min run time. No vent to the outside!

[@markhoffman]

I have a Bosch electric condensing ventless dryer. Works great, love not needing a vent.

[@GilesBrowns]

@@buildshow Hi Matt, I'm in the process of self installing a heat recovery system in the UK. Your price estimates are about the same here too. I've also had a Miele heat pump dryer for 5 years in a small utility cupboard stacked ontop of the washing machine. It works billiantly but I decided to put a dedicated heat recovery extract vent in there to remove the slight tumble dryer smell of hot clothes. Even before intalling MHRV, I liked the fact that I wasnt wasting energy blowing hot air outside.

[@Spooms1961]

James Gleason because extra venting work equals cost of equipment and builders time! All saved by not having to need to vent a dryer.

[@markhoffman]

@@JamesBlazen Switzerland has outright banned vented dryers since 2012. Heatpump or electric condensing dryers are the way to go. Heating up air and then blowing it through clothes and then right outside is very wasteful.

[@wjthehomebuilder]

I have literally been waiting for this video!!! Thank you!

[@wjthehomebuilder]

10 months later, I just got a quote from my local Zehnder distributor for an upcoming basically Passive house build. Thanks again Matt for the video!! Next on the list, EAS windows.... Here we go!

[@slamrock17]

We love you Matt! I recommend your videos to all my friends.

[@buildshow]

Thanks Pete!

[@simeonkessler906]

An impressive system. I wish matt would compare the total cost of something like this versus the traditional ERV with brach ducted system and multiple fart fans in each bathroom. 10-12K plue 5-6K in labor seems like a whole lot compared to the other system that was being used.

[@theseismicwavesmongolia7720]

Really love the video, the explanation is very easy to understand and follow through! Thank you Matt!!!

[@williambardin6487]

Great improvement over all those individual vent fans, and holes. I'm curious about the dryer vent, kitchen hood and the air conditioning. Are they integrated into this system somehow, or are they stand alone? Also it would be nice to see how you get from the attic to the master bath and master bedroom on the first floor. Great videos! The more I watch, the tighter my house gets (and more expensive). I would like to see videos of how your associates, Wade & Jake, and even Steve apply these designs and equipment in zone 5 construction. I'm building in NJ so it's a little different than Austin. Thanks!

[@TroyRibao]

Fantastic video. In a future video could you go over how you will manage your dryer? Venting, make up air, special location if any, special door/windows if any, etc?

[@MultiYlin]

impressive product, hopefully, they will engineer a more compact system for the Chinese market. I don't think my 250m2 apartment has the equipment room to fit an amazing system like this.

[@khandam7709]

lol 250m2 is huge, this is probabaly made in china already.

[@TheGgbk]

looks like a dream house to me - i suppose my dad would be a little skeptical of a fan and plastic tubes for that price but for me i'd nerd out on it

[@randallrister4773]

Matt, curious about some things on this system. What is the monthly electric cost? What is the average filter replacement cost? How would this system work if you wanted to have a fireplace in your house? How would the possible smoke effect the system or would it damage the system?

[@thomasschafer7268]

40 watts/h. Yes if your ofen has a secondary wir from outside by pipe. And normal Filter need 2 20€ /pair

[@larrylarrypage]

Stupefying !!! Really set by set guide to make a shed

[@edc1569]

In the UK you definitely have the inlet and outlet on the same wall, avoids all sorts of balance problems from the wind, not sure why you'd set it up differently - solar gain?

[@billyyoder8171]

Thank you Matt. Good job. Have a blessed and safe week to you and your family.

[@P8qzxnxfP85xZ2H3wDRV]

I'm really impressed with this house. This is clearly the future. You only showed the air supplies though. What about the exhausts? On another note: Have you thought about complete energy self-sufficiency all year round with solar panels and a hydrogen storage system? That would certainly be the icing on the cake.

[@holychitlingravy]

See 13 minute mark in video, he discusses exhaust.

[@kawkvulcan500]

I was thinking about the same thing, but you'll have those exhausts at each bath, range hood and whatever else you need vented.

[@AB-yt4hd]

I have added filters on each exhaust vent to protect the ducts. After 6 years, my ducts are still perfectly clean.

[@damhock]

I would strongly advise to think about the pipe cleaning right away : avoid tight 90 deg turn and regular acces to inlet pipes. Otherwise you might start to have allergy problems after 5 years. I m hvac engineer from Belgium.

[@GilesBrowns]

How do you clean the semi-flexible ducting?

[@Floreypottery]

Giles B they are smooth inside duct cleaning machine for small ducts

[@mennomateo]

Filtration and Maintenance ever 3 months at the HRV/ERV will help keep the supply air clean

[@GilesBrowns]

@@Floreypottery thanks, I've got a few 90 degree bends but mostly on the extract ducts.

[@sepertude]

You cant get mold because of the MERV13 filtration at the entry point and than MERV15 on top of that.

[@sk241693]

I just installed a Multistack ERV in Manhattan for a new 8 unit building, built to passive house and LEED standards. Amazing indoor air quality thus far and low energy costs.

[@matekochkoch]

Matt is like a proud father.

[@PeterPutz82]

Great system, very timely info too, been wondering about ventillation systems for tight houses in cold climate. One question, how does rangehood air get dealt with if potential oil and grease gets sucked into the system? Does the range have it's own set of filters?

[@mtscott]

Great question. I wondered the same myself. Surely there has to be a seperate system with a damper.

[@charlesarmstrong3536]

@@mtscott Most hoods will have filters that catch most of the grease. But a well designed kitchen will have its own makeup air system for tho hood. It doesn't have to be an expensive set up, just a powered duct fan system that brings makeup air in around the bottom of the range. They have solenoids that turn the makeup air supply on when the hood exhaust is turned on.

[@dave.lenton]

This was addressed in a more recent video. The range hood is *not* connected to the ERV/HRV. Besides the oil/grease issue, there's just too much air. High flow range hoods do 600-800 cfm. Matt's ERV is under 200 cfm, so it would never be able to handle it. In his house, he has an intake fan (with filter) to balance the range hood, that's powered when the range hood is on.

[@wernwerks819]

I watched the video hoping that the topic of kitchen exhaust would be taken care of. I want to have plenty of BTU of cooking power, but want to know how to handle getting the wok smoke and other serious air concerns handled. Thank you for the content!

[@SpecialKthx]

I install HRV here in Quebec, the cheapest one with install start at around $3000CAD and maybe $3500CAD for a ERV. I think this system is expensive but I like the fact that it auto-balance, your system at $15-20000USD installed is quite expensive but maybe its meant for people with deep pockets, you can usually sell your stuff at higher price to those :o

[@FelipeSQ04]

Where do you get your supplies, from?! I was planning on a retro-fit into an older house here in Quebec, built in 1985, that the guys installed an Air Exchanger in the Attic! I have been looking around to find either someone to give me a cost run down or DIY this thing, but can only find the box store HRV/ERV's and they don't look tempting at all!

[@SpecialKthx]

@@FelipeSQ04 entry level hrv from venmar, aldes, lifebreath, any hvac company can install those at around 3000. The suppliers doesnt sell to normal people but at Canac, you can get the nektra and its basically a lifebreath

[@FelipeSQ04]

@@SpecialKthx Thanks a lot, I had read that some places only sold for hvac companies, so I thought it made sense to confirm with you. Will try to go through the Renovert program to make this change, since right now the air exchanger in my home is in the Attic just pushing winter cold air inside :D Thanks a bunch!

[@SpecialKthx]

@@FelipeSQ04 I suspect you have a asthon or a venmar econo/pro If you have a 2 story house it will be more complicated but a 1 story with basement not finish or with removable tiles will be easier. You might have to sacrifice a corner of a closet tho.

[@mrafati]

@@FelipeSQ04 you also can check www.epurair.com/en/products/. They are Quebec based company and produce good quality residential ERVs.

[@roobixtube]

Matt, I love the content of your channel. I used to build Passive Houses in the northeast. We used Zhender HRVs all the time - they are great products. I'm so glad to see this content getting out to a broader audience. Now for the constructive criticism - you've GOT to get your camera person a steady cam or gimbal system. I'm getting motion sick with all the fidgeting and adjusting (I've noticed this on other videos too, especially if there's a tour or "let's move around and see this house" component). I mean this with only the best intentions. I love your videos, but nausea is no fun!

[@BrianKrahmer]

it's better than the audio normalization :)

[@jdrissel]

That is an awesome system. I do have a question. If say you are having a party or work is being done so lots of doors open and left open for longer than usual, could the system have a mode to run positive pressure while the doors are open? It seems to me that if you tried to go positive pressure but failed, we could assume a door or window is open and just keep the flow on. When it goes positive, switch back to balanced mode and every once in a while try to go positive pressure. This could also warn of envelope failures... Try to go positive pressure at sometime between 3 and 5 am (or whenever you expect very little activity) and if it fails several days in a row, send an alert.

[@christophersmith1894]

Good question, James. The fans can be set to be positively or negatively balanced up to 15%. The advantages/disadvantages vary from one climate to another. Also, you can temporarily turn off either the supply or exhaust fan.

[@lifeisgood339]

Dude I've never liked build shows on tv your videos are so much more informative than any of that shit!

[@keithjanssen8568]

Matt, could we have another episode on "Dryer Venting"? I am interested in how you are doing this. Following your build.

[@GrayHouseStudio]

Will you still be running a separate dehumidifier? I’m putting together my HVAC system for my new house construction and I’m loving your fresh air system

[@sorrmalify]

Same question here.

[@CompCrasher86]

Matt always does this in his builds now. I’d be shocked if he wasn’t running a discrete dehumidifier as this system isn’t really intended for dedicated dehum.

[@AnthonyBrusca]

Of course, he is putting all of HVAC+D separate hahaha.

[@kadmow]

@@CompCrasher86. And it isn't connected to the "H and AC" part of the air system. (A downside really - it should be plumbed right into the dehumidifier input to the recirculating ducted Reverse cycle AC.

[@StariusPrime]

I want to see how heating, cooling, and de-humidification is all tied into this system too. I'm not quite sure how those pieces of the puzzle fit together.

[@tantricsphinx]

Phenomenal video! Thanks for this and so many other highly informative contributions.

[@tubastud06]

"... Check it every quarter..." Yeah, sure, ok. I'll check on it in two years, thanks man.

[@ArthurDentZaphodBeeb]

Yes, this one my biggest pet peeves - these are expensive-to-design ($3-$5K), expensive-to-install (these complex HVAC systems can easily run $50K) and expensive-to-maintain (filters cost hundreds every year - IF you even know they need to be replaced). These are 1%er systems or virtue-signalling systems, not Average Joe Homeowner systems. Granted, Matt's audience isn't Joe Homeowner, but it bugs me that there's no acknowledgment of this - despite the cost consistently being a major concern in the comments.

[@tysleight]

@@krinohs I'm lazy by nature. If it is hard to get at I'm going to put it off. Having a beautiful system in the attic means to me out of sight out of mind. Also if I followed all of manufacturer service intervals my life would consist of nothing but work and servicing all my ______ and sleep. Ps. It is wed and I'm going to hit my 40 hours in about an hour and I have alot more to get done before Sunday. This is more than normal but not out of the ordinary for me or my co-workers.

[@tubastud06]

@@krinohs You seem like a fun person.... You ever heard of a joke? Yeah, I know how to, and, more importantly, do preventative maintenance on my major appliances. I was just making a J-O-K-E about it - Because there are people who would do it.

[@Rebasepoiss]

​@@ArthurDentZaphodBeeb Interesting that a system like this is considered "exclusive" or "for the rich". In Estonia (where I live), heat recuperating ventilation systems are pretty much standard for every new apartment and house built, irrespective of the cost of the place. You pretty much have to install them if you want to meet minimum energy efficiency requirements. A lot of these systems actually come with control units that will remind you when to change the filters and it's more like once to twice per year not every quarter. The filters themselves are usually between €20-30 so you're looking at maybe 20-60€ per year in filter costs, depending on how often you change them. What you get in return (at least in a cold climate) is huge savings in heating costs because most modern systems are at least 80% efficient, many have an efficiency rate over 90%. A house or apartment building with natural ventilation will lose 20-30% in heat via exhausted air. Even old apartment buildings that are being renovated will have heat recuperating ventilation systems fitted. You can watch a Zehnder system being fitted to an old apartment building here: kzbin.info/www/bejne/b37ZoYWqm56Dp8k

[@tysleight]

@@krinohs thanks for winning a bet between my wife and I. I said I can say 1 thing mid comment say something else and someone will call it out. I got lunch out of the deal, So thanks

[@mouatibmouatib6914]

I am a son of a house-builder and I can tell you :" I LOVE YOUR VIDEOS".

[@christophersines8238]

As a duct cleaner I like this. Another system to get paid to clean.

[@rtoews9396]

Sounds like this would eliminate the standard trunk and branch system. Just a different type of cleaning.

[@valkyriefrost5301]

You'll need to invest in a couple of 3 inch (75mm) brushes. ;-)

[@Mrcaffinebean]

Not really. Why would you clean the exhaust ducts?

[@davidhazen6134]

Well this discusses how in the north its HRV but still acts as a filtered fresh air. I always felt that an open widow is the best, but since I have this experience of in home moisture to actual dangerous levels, I feel that legitimizes these types of air movement systems

[@stuartbrock7586]

I would like to see how the dryer vent is hooked in. I am also curious how the kitchen fan vents through it.

[@buildshow]

I’ll have a separate system for the kitchen exhaust. I’m using a heat pump dryer so I won’t need a vent

[@FlyBikeCampAK]

@@buildshow Any particular reason why the kitchen exhaust isn't being integrated with your Zehnder system? I'm very curious how these ERV/HRV systems can integrate that exhaust since they typically require a substantial flow rate but only when called upon. I like the idea of one exhaust penetration for the whole house, I'm just not quite sure how that can be managed with these systems. Also, how are you managing the evaporated moisture from your heat pump dryer? I would think you would still need a vent for that. The heat pump in the dryer is only a heat source to facilitate evaporation of moisture from the damp items within it. Also,

[@paperwait9611]

@@buildshow even if you had a dryer vent, the q600 can adjust supply and exhaust rates in response to the dryer exhaust. by not having a dryer vent, you are putting a big humidity load in your building envelope, and the zehnder system shown does not provide humidity control. so you would have to have mechanical systems (force air conditioning and/or dehumidifier) to provide humidity control. some people go for a recirculating hood, but a kitchen exhaust is going to work better. i have a heat pump water heater and considered a heat pump dryer but concluded that it really didn't do much and was pretty much a waste of money.

[@paperwait9611]

you definitely don't want the kitchen hood tied to the dedicated outdoor air system. the grease and residue from cooking would gum up the ducts and the filter at the erv. you don't want the dryer vent hooked in either because the filter in your dryer does not capture all of the lint. the only things you want going into the return ducts of the doas are odors.

[@FlyBikeCampAK]

@@paperwait9611 You make a good point about dryer lint. That would inevitably build up in the ducts, except the Zender duct tubes appear to have a smooth surface finish and the interface with the manifolds also appears quite smooth. The manifold boxes could be problematic though. Not only is there particulate in the dryer vent air but also a lot of moisture and don't forget heat. In the summer time you would not want to transfer that heat to your supply air which an ERV/HRV would do; you'd be fighting your AC system with your ventilation system. The moisture transfer could also certainly be problem if you don't already have a dehumidifier in the system. Like you said an ERV is not a dehumidifier, unless of course the exhaust air has a dew point lower than the incoming air, then the core would condensate...there is a degree of humidity control inherent to an ERV since enthalpy accounts for both sensible and latent heat. Regarding the kitchen vent, presumably regardless of direct vent or tie in to a residential DOAS (i.e. ERV/HRV) a grease filter should be present. Recirculation vents do not adequately manage odor, smoke, or steam... they have very little benefit at all frankly. That said most kitchen exhaust hoods call for 150-400CFM would could be equally just as large as the ventilation needs of the house. So do you upsized the DOAS to include the kitchen or accept the needs for another vent? Kind of seems like you really need three vents to avoid any problems Kitchen, Dryer, rest of the house. Problem is the DOAS would need to compensate for the Dryer and the Kitchen exhaust with supply air, so you'd still need some kind of tie in or dedicated direct air inlets for those areas, but then you lose efficiency by not tempering that makeup air.

[@andyvaughan5901]

This is a great system however I have two concerns: 1 - What is the noise level at the exhaust grille? 2 - Does the Enthalpy filter actualy reduce the humidity from the incoming air? Love the show, thanks in advance for the answers and your opinion

[@rud]

If I can’t smell farts from the bathroom, 2 minutes later in the kitchen, it hasn’t been done right. 🤪

[@jtr82369]

That is an amazing setup

[@kencoley1likes]

Hi Matt, I have questions. I love this system and wanted one forever!! 1) So your dryer and kitchen vent do not vent to the outside? What about cooking grease and dryer lint? I would think you would still want venting to the outside for those. How are you cleaning those particular contaminates 2) In your experience would this system eliminate dust like a clean room? Could you do a test on this once you get the system up and see what level of dust and pollen accumulates inside your home. 2b) In your experience, does HEPA filter systems added to HVAC system remove dust and pollen at an effective, almost clean room like level. I would love to see an episode surrounding these questions. Thanks.

[@MrJramirex]

I second this.. I'm also interested in your kitchen vent set up. I was thinking of just having a smaller hood vent and fan for an induction cook top but if I can avoid it with a system like this then thats a massive plus. I want my house to have minimal vents due to being in a wildland urban interface (high fire zone). For the dryer I'm thinking of having a vent installed for future proofing but sealed and use a heat pump dryer. I'm curious if you are doing the same. Thanks!

[@dan123collins]

Stuff like this is what we need to be code / standard, in the UK the overwhelming majority of new builds ( no matter the cost ) have no MVHR or anything like that. You get a gas fired boiler wet central heating, extractor fan in your bathroom and maybe kitchen, then trickle vents in your windows 😞

[@basiaboy]

Matt, can’t you use a motion sensor to activate the bathroom fan that activates the countdown power?

[@Justaguy0420]

Any BAS with door switches and motion sensors will accomplish this for you. HVAC controls and window blinds are also common in a BAS. Some DIY guys are using raspberry PI’s to accomplish this rather than expensive tridium/niagra proprietary programming and controllers.

[@Justaguy0420]

TJ Challstrom Humidity sensor won’t close when you just want to take a shit in the toilet. Make up air would have to be balanced with the same cfm as the fart fan. Wouldn’t want to create negative pressure in the space and pull more air away from the other zones. None of the other duct runs have motorized dampers on them. Constant speed fan at the ERV.

[@mwatkins2464]

TJ Challstrom all you need is a thermostat with a cap tube connected to the hot water line to control the fan. The water line heats up when hot water is used thus turning on the fan anytime the bath water is used. Low voltage to. Add a 15 minute time cut off delay and it will run 15 minutes after shower is stopped. You’ll never have to worry if someone forgot to turn on the exhaust fan again. It’s simple

[@CompCrasher86]

This is great. I have so many questions because of how fascinating and unfortunately uncommon the tech is in today’s homes. What’s the maintenance? Does the core need to be cleaned? Is that prefilter going to get overloaded? I’m thinking pollen vacuum on the side of your house. You run multiple duct runs to each room to set your max airflow and then you fine tune it with the registers? When flow hood the register, won’t the self adjusting throw off all the other registers you just adjusted? If its in boost for somebody taking a shower won’t every other room be boosted as well? Whats the strategy to prevent a “draft” feeling from the cooler fresh air? Here in the north the outside air can be 70* cooler in peak winter. Will airflow between intake and exhaust rooms be enough to open/close doors? I love the approach you’re taking here and I hope it takes off. I can’t wait to see this integrate with smart home and IoT products.

[@kadmow]

I wonder how long semi-permeable membranes in ERVs will last - in a jacket some break down within 5-10 years. A HRV has more durable partitions - but no vapour permeability

[@renderwood]

Pretty sure the core needs to be replaced at some point also. Typically you can vacuum them at least, but unsure if that can be done with this one? I expect the core to be expensive to change.

[@christophersmith1894]

The core should be removed and cleaned every year. Vacuum the edges and run fresh water through it (warning, though, not all ERV cores are water washable like this one). Our filters should be checked like almost all filters on a quarterly basis. Yes, the Luna diffusers provide adjustment to compensate for the varying duct lengths. There can be a couple iterations of adjust registers, but the fact that this Q600 ERV adjusts automatically to maintain the total flow helps make the process a lot easier. Yes, boost is for the entire system (there's no "zoning"). High heat recovery and relatively low airflows are sufficient to avoid cold drafts. Yes, the airflows in each room are usually low enough to move freely around/under a closed door.

[@CompCrasher86]

Christopher Smith thanks for taking the time to answer.

[@wjthehomebuilder]

33:26 While some may be concerned about the Zehnder cost set up (or operating costs - which are really not bad at 2.4Kw/ per day) I can see the Zehnder system taking place of additional mini split units that would have otherwise been needed throughout the house. So yes, this unit costs a bit more, but the HVAC bill is going to be half!

[@kadmow]

edit kWh - Energy rather than power. NB. This isn't an AC unit - it is additional, for air quality, rather than "comfort".

[@wjthehomebuilder]

@@kadmow I know that an ERV system is for air quality. My point is that when you have such an efficient air distribution system such as this Zehnder ERV, you eliminate the need for additional mini split units throughout the home because this system will continually distribute air around the house.

[@wjthehomebuilder]

@@JamesBlazen I understand that. Matt has already stated that he will be utilizing mini split heads in his home. My only point was that this Zehnder system offsets the cost of installing mini splits in; say, every room, which I've done. Next time, I would consider the Zehnder option and save the cost of at least half the mini splits. The bonus is getting the fresh, filtered, heat recovered air that the ERV provides. (A requirement anyways on a house that is under 1.0 ACH.)

[@wjthehomebuilder]

@@JamesBlazen Energy recovery. That includes heat and A/C

[@raypasour5259]

I have been a fan of your videos for a while now; but to hear you mention God just makes me want to watch you all the more!

[@richardteychenne3950]

Great episode, only thing you didn't cover was how the life expectancy and guarantees compare to the alternatives. e.g. Typical bath fan lasts what 5 years so long term costs are probably lower for Zehnder?

[@carrerahorse]

Nope, didn’t cover my passive solar home in CA!

[@jl9678]

I was just thinking that. 30k system to save $20 a month and replaced after a few years? First world solutions

[@BrianKrahmer]

@@jl9678 where did you come up with 30k? he mentioned 10k, but that is for a pretty large house

[@jl9678]

@@BrianKrahmer 10-12k is just the equipment package. If I know anything about hvac it's that the labor is usually 1 to 2x the equipment price. Hence the 30k

[@BrianKrahmer]

@@jl9678 if you're willing to pay 20k to install a system like that, drop me a line. i'll fly over from europe just to do that. at a labor rate of $100/hr, you're talking 5 weeks of work. i'd be disappointed if i couldn't install that system in less than a week. i'd honestly estimate 3 days

[@jasonjohnstone686]

Thanks for making this video, info was spot on for someone looking at using a similar system.

[@Mercer1012]

Hey Matt, could you make a video that shows how this will integrate with your Mitsubishi heat pumps? I am not understanding fully, is there an air-handler and rigid ducting, or is *this* your ducting? Thanks so much for your videos, I am definitely implementing this in our build.

[@sitechca70]

This ERV is installed independent of the home's HVAC system. So it does not integrate. Quote from Zehnder "It is essential that the ventilation and HVAC systems are separate and do not share ductwork. This ensures proper airflow rates and energy efficiency". So basically the homeowner will be paying about 2X.

[@skmetal7]

@@sitechca70 How does this not suck all the heated or cooled air out of the rooms and send it outside?

[@sitechca70]

@@skmetal7 That's exactly what the ERV does. Look up how it works. I'm no expert here, merely a residential homeowner who has looked into the benefits of one and decided it wasn't worth it for my house and climate.

[@myhandletre3]

@@skmetal7 just look at the whole video, it is explained.

[@jtmcanada234]

... 12 CFM per tube ... That's Awesome...

[@curtk8715]

was waiting and waiting for the talk about the exhaust fan in the kitchen does that air get recycled out the unit - if it does how are you trapping the grease particles.

[@kadmow]

Matt answered in another post - no that dirty air ( and, strangely - makeup) - is separate.

[@rjdverbeek]

Don't forget that your doors must have a gap at the underside to allow for the flow of air between rooms and bathrooms/kitchen

[@ThePositron2]

To save anyone else from doing the math about how much 100W will cost you a month, given avg. Texas electricity price of $0.11/kWh. 730 hours * 100 watts / 1000 * $0.11/kWh = $8/mo

[@jhilling]

While this is a useful calculation, you need to pro rate the cost of the system and the maintenance of the system over its life. Additionally, if you're considering putting this in an existing home, what are your cost going to be to make the home tight to take advantage of the system.

[@JM-fx8qv]

Minus the cost savings what would be the delta? still cost (- out of pocket) or benefit (+ in pocket).

[@zack9912000]

Yea that's a great savings but what the marketing wank and builders don't tell you. The huge upfront investment to buy it and the high cost maintain/ repair them you WiLL NEVER makes your money back. I work and install these systems daily and I would never want this in my home or a ultra tight home. Cost of one of these systems I can buy 2-3 of a high quality mid range efficiency system that doesn't break the bank to repair or run. I can actually make my money back

[@quacktony]

Been waiting forever for this, thanks Matt

[@quacktony]

Those new ducts are awesome but should they still be insulated?

[@ThePositron2]

@@quacktony they're all running inside the insulated space and they're not really carrying conditioned air anyway.

[@veovius]

Do you still use a separate range hood or does that tie in to the HRV as well?

[@mennomateo]

Range hoods can not be exhausted through an HRV/ERV potential for a very dangerous situation. Hood fans can be paired with a powered makeup air system... I believe Matt has so video regarding this situation

[@Justaguy0420]

Naaaaa man. What’s the worst that could happen. Straight weld up some grease duct and call her good bud!! Whats ASHRAE???

[@leet0809]

Great video. Very detailed. Good questions asked.

[@markpalmer5311]

More questions: make up air for a big vent hood? And if we upgraded our 2013 ERV, do we just remove and plug the existing bathroom fans and exhaust system?

[@MrTiger0002]

I got 1200CFM Kitchen Vent Hood... have yet to install a MUA yet... Does this system compensate for that or is an extra MUA still required? I also use fireplace in winter... so sometime the smoke is terrible in bad burn. Another headache... However, I do like this system.

[@sergeybebenin]

Why not hook up to existing fans? You can probably even remove the motor and just leave the grill/shell of it

[@valkyriefrost5301]

@@MrTiger0002 - The short answer is No. A 1200 CFM hood should have an exhaust duct of at least 10 inches (12 inches is preferred). That means you'd need a minimum 10" MUA duct. In reality, you'll want the MUA duct to be larger (much larger) to cut down on the inflow air velocity and noise. Both of these base values are larger than the entire EVR system supply capacity. The same would apply to a gas furnace. don't use conditioned air to feed the fire, run an outside supply for the furnace and keep the entire combustion process separated from the living space.

[@MrTiger0002]

@@valkyriefrost5301 Thank you. Confirms my thoughts.

[@grahamd.8713]

While the system may be auto balancing to always maintain that 180cfm, it's going to take quite a bit of back and forth tinkering to get each vent in each room dialed in. As you dial in the vent in one bedroom to say 10 cfm, it's going to effect the flow at ever other vent in the house by some amount. As you work your way around the house and dial in each vent to the flow you want, the vent you started at is not going to be 10cfm anymore because of the adjustments made elsewhere. Perhaps it's a negligible amount and who cares, but I could see a person having to do a few complete cycles of adjusting at the vents before the effect is no longer measurable. Seems like a great system though.

[@PiraticalJess]

It's probably analogous to a "pump-up" leach field. Start out with everything wide open. (In this configuration, most of the flow will be through the shortest duct run.) Then, beginning with the shortest run, turn down the vent until it's flowing like you want it. You may not have to turn down the vents on the longest runs at all. Only duct runs with similar drag would need to be adjusted simultaneously.

[@staceyj5835]

So is this the heat and ac all in one or just something for ventilation/fresh air? This is a pretty neat system

[@egghead0]

Just fresh air/vent. He mentioned he also has a mitsi AC system.

[@Edgardocelectric007]

It’s a great video really liked it, it’s answer so many questions about ventilation, I only have one what about kitchen stove venting. Hope you cover that question soon.

[@buildshow]

Coming soon. Separate system for kitchen exhaust and make up air

[@rogerwhiting9310]

I made the mistake of putting the intake and the exhaust fittings of my air to air heat exchanges on the west side under soffits 10 feet apart. In Massachusetts the predominant air is from the west. When the weather outside is windy it blows untreared air right through the exchanger. This means cold air in winter and hot air in summer BLAST right through the exchanger into my house vents. Make sure you tell people to avoid intake and output from prevailing wind side of house.

[@HectorPerez-tb8hn]

keep in mind that if is man made it can be fix !!

[@nicolascardillo7615]

Just 1 solar panel of 400 Watts can run this system for 10 years or more for free (after the cost of solar panels, Battery, and control system) and still have some extra energy to spare. He said this big system would use about 100 Watts, so about 2,400 Watts a day. The average day is exactly 12 hours, the power you actually get on your panels is equal to about 6 hours of full sun radiation per day. Therefore 1- 400W panel (or 4 - 100W panes for lower price but need more space) would create 400Wx6=2,400W a day. Now, this house has a great large open space for multiple arrays of solar panels systems and since his whole house is running on electricity he can practically run the entire house on solar. He does not even need a battery backup and just connects the Panels to his Electric-Miters and the power production would be subtracted from his Bill. In some states, if u produce more power than use they would even pay u for the extra energy u give them. Now since he lives in Texas a really hot n sunny state his power production would be even higher. I would have a backup battery for emergencies since Texas Power System SUCKS! WHY THE F***!!! Texas is the only state in the country that is outside the National Power Grid?

[@robhardy1109]

Matt, in Canukistan our building code calls for a 'principal fan switch', usually located in a hallway or other common area. It's linked with a bathroom exhaust fan, usually the largest CFM unit, and fires a relay in parallel with that fan when either switch is turned on. This relay closes terminals R and G in the furnace through a jumper. Every time that particular fan is used in the bathroom, which is several times per day, or someone uses the principal fan switch, the house has air changes exchanges. We usually use timers for one or both. Is the air feeling stale? Just hit the 30 minute button on the principal fan switch.

[@online_screen_name]

What a wonderfully informative and interesting episode, love this series. Question: What happens to the hood extractor in the kitchen? I would think that greasy/oily exhaust air is best kept away from this system?

[@buildshow]

Yes we have a separate system for the kitchen exhaust

[@online_screen_name]

@@buildshow thanks for getting back so quick. And thanks again for sharing all this insight.

[@IceyMyst]

Can this really handle exhaust from a high cfm range hood? Does it negate the need for a make up air source for a range hood?

[@brennangervais6845]

No way

[@SmartMass]

That was my question as well, not to mention I've cleaned exhaust hoods in houses before and it's not just clean moisture that travels through, I'm not sure I'd want an ERV to handle it.

[@buildshow]

No. I have a separate system for exhaust at my kitchen range that will also have a make up air system

[@ghulands]

@@buildshow can you do a video on it please

[@nuevocomienzo9571]

@@buildshow what are your thoughts on active makeup air systems like the ones made by Fantech? Also - is using a gas range not feasible in a Passive House if we balance the range hood with an active makeup air system?

[@RonRawson1]

great video Matt I need some of the vent pipes and tubing.. Awesome buddy cheers

[@cthompson658]

I wish Canadian suppliers would stop sitting on there hands and start carrying the product you have available down there

[@compactc9]

Its not just the suppliers, it's the buyers. Up in Canada, central vacuum systems are very common, most new houses have one. Not as common down here in the US, not for a lack of suppliers, as we have more of them, if you can believe it. Sometimes I think the buying public in the US has gotten cheap, and unwilling to consider the benefits of spending money on something like a central vac, or this air system.

[@georgeian3243]

This particular unit doesn’t make Energy Star ratings and really isn’t meant for harsh winter conditions, maybe Vancouver but not around Ottawa where I live. I read a bit of their literature, they say the supply air will likely be somewhere around 16.5C when the outdoor air temperature is -10C. That’s cold! My HRV is Energy Star rated and is at least 75% efficient at -25C. It also has a passive defrost system. They don’t even mention defrosting the core in cold weather, I’d want to have a long conversation with them before installing one in a cold climate.

[@compactc9]

George Ian I checked their website, and other models have varying features, I assume different variations suited for different climates, and some of them mentioned specifically frost protection. Being he’s in Texas, his unit likely does not have this, as you noticed.

[@Rhaspun]

@@vinski_ A too common attitude in the US is that bigger means it is better. Quality isn't a commonly used word.

[@ArthurDentZaphodBeeb]

@@compactc9 Central vacs are a pita and don't work anywhere near as well as top-quality push vacuums. We stopped using ours after a few years. Until you mentioned it, I had forgotten we even had one.

[@bobbowling2923]

Good product. My service was the worst in my 50 year business career. I am sure your service and commissioning was good because this was advertising for Zehnder with some free product. How dependable are your recommendations when you are paid with free product?

[@enduman]

Rumor is someone farted in Matt's house at Thansgiving dinner, and you could still smell it at Xmas time.

[@HectorPerez-tb8hn]

that's what I was talking about lol !!

[@nickjudson1179]

Matt, I have a Q in my PH and the feature I like the most is that it has a built-in humidity sensor. If you set the unit to 'automatic', it will increase airflow as it senses increased humidity levels. I didn't bother to install any boost switches - just the app on a wall-mounted tablet in the kitchen. The unit automatically spools up when people are showering or there is some serious cooking happening. I would have liked to have installed other sensors, but they weren't in the budget. Material costs for a ComfoQ without the extra filtration is around 10K in Canada. The nice thing is that the app will let you know when your filters need changing.

[@paperwait9611]

what the q can do is remove air and most of the humidity in that air. but it isn't really a moisture control system. it can only remove humidity from your house if the humidity in your house is higher than the humidity outside your house. that is probably true more often in canada than it is in texASS, especially during the colder months. when the humidity of the outside air is higher than the humidity of the air inside your house, some of that humidity is going to come into your house, and you will have additional latent load (presumably your manual j analysis took that into account). there are dedicated outdoor air systems, like the cerv2, which can provide moisture control. the cerv2 uses a heat pump instead of an enthalpy core.

[@nickjudson1179]

@@paperwait9611 Yes - I'm in a climate where I don't need to worry (much) about humidity or cooling. Cerv2 looks interesting. Fingers crossed Zehnder (or someone else) will bring/manufacture a 'magic box'.

[@moonshinewarrior]

My question with an erv is when you’re exhausting humid air after a shower is the erv not transferring the humidity to the fresh air, therefore defeating the purpose of exhausting humid air to start with

[@yamspaine]

the cooler air from the inside cools the air coming in. that causes the humidity to drop out. the humid air from the bathroom goes out

[@christophersmith1894]

...and these intermittent shower events are just a blip when you're using continuous ventilation and considering the whole volume of the house. Your point is valid in that there is some quantity of humidity staying in the house with moisture recovery, but it's very short-lived in the scheme of things. The continuous exhaust from the bathroom long after the shower is over keeps the bathroom mold-free and that perpetuates good air quality in your house.

[@shang616]

Questions: Sending range hood exhaust through the ERV? Would yhemat grease mess up your ductwork? Sending bathroom exhaust through ERV? Wouldn’t that be retaining unwanted moisture inside the house? Thanks in advance for your responses.

[@brianwright9514]

I'm concerned that this is not giving you enough kitchen ventilation to prevent cooking particles/oils from getting suspended into your household air. There were a couple recent studies that found relying on these ERV's alone do not sufficiently maintain indoor air quality after cooking, taking hours to recover after cooking even in boost mode

[@juzoli]

Brian Wright If you have electric range like Matt does, it will be not that much of an issue. Most of the bas stuff is coming from the burnt gas. The rest is just smell, which some might even like it. Considering that, the biggest issue will be the moisture, not the air quality.

[@brianwright9514]

@@juzoli this study indicates otherwise... www.sciencedirect.com/science/article/abs/pii/S0360132318305183

[@buildshow]

Brian, I will have a separate system for my kitchen exhaust and make up air. I’m using a Fantech system

[@chiendog1053]

I am planning to build a new house with a first floor master suite. In the future we will finish the lower level where the other 3 bedrooms will be. Just me and wife now but expect grandkids in the future. Would you recommend installing 2 separate smaller systems, one for each floor? The house will be nearly passive and therefore very tight. The house is a 3000 SF ranch with a walkout lower level. Feels like a very large system with a lot of long runs for a single system. Thanks for your help.

[@brad7571]

I get the urge to build to this level - but at the end of the day, a 25kW solar system still gets me to net-zero at a much lower cost after rebates. 26K to power an all-electric house (electric cars included). I have 4 Panasonic ERV's running 24/7 without any electric bills. I still get it and I like it - I'm just torn with the expense, engineering, and volume of materials that need to be dealt with. Not that my house is any slouch in the insulation, geothermal, or window department. . .

[@chaseweeks2708]

If I've got the money to afford it, I'll get as nerdy with my HVAC system as I can. Never forget the nerd factor. If I put one in my house, I'd get endless hours of annoying friends and coworkers about how it works. Worth every penny.

[@CompCrasher86]

I’d like to think that the comfort factor will justify the cost. Imagine being spoiled by engineered comfort. Downside is noticing anytime you’re in somebody else’s inefficient or unhealthy building.

[@Lenser]

Running ERV 247 is way excessive.

[@Rebasepoiss]

California already lets solar electricity go to waste during daytime since there isn't enough demand, for example.

[@karthik11512]

Rebasepoiss that will likely not be a problem in the coming years as EV adoption goes up. CA needs to open up the grid so that residential storage can be a supplier, they have so much potential. It’ll likely happen sooner in TX though because of the open grid market (huge advantage)

[@michaelfore1418]

Does the dryer exhaust connect to the ERV system or is there just an exhaust port in the laundry room?

[@Beastphilosophy]

Can you show the ERV's performance with a psychometric chart?

[@christophersmith1894]

Yes. Feel free to reach out via our website zehnderamerica.com and we can show you an example.

[@tauruslake6918]

GREAT video and informative!

[@nordlands8798]

4:56 good you went higher than that, as this seemed low compared to equivalent Norwegian building code requirements of minimum 15 cfm per planned sleeping place and 0.065 cfm/sf for living areas.

[@holychitlingravy]

Yes, I wanted to make a similar remark, but your standards were even higher. Explains why I enjoyed my sleep so much in our long term stay apartment in Norway.

[@Dead_Aim556]

"WOW"-M.R. best line of the entire episode lol

[@ericwilliams4465]

Since this is independent of the heating and cooling system, when the humidity is high, aren’t you just bringing in high humidity in with the outdoor air? Why not just connect the incoming air into your HVAC return air duct system so it gets cooled and dehumidified prior to getting released into the house? Even with the claimed 85% efficiency, you are still adding humidity.....

[@willyshopdotcom]

Moisture from the incoming air exchanges with the outgoing air (the same way heat does) so you get the dehumidification for (almost) free. That's sort of the point of the unit. The exhaust air will have roughly the same temperature and humidity as the inlet air and the outdoors, and the supply air will have roughly the same temperature and humidity as the return air and the indoors.

[@ArthurDentZaphodBeeb]

AC systems are lousy dehumidifiers. And in humid shoulder months when AC isn't running, doesn't help at all. Need a separate dehumidifier. The Zehnder is needed because Matt is building a super-tight foam-encased box and it's literally unsafe to live in without full-time fresh air.

[@chaseweeks2708]

My guess is that they are relying on the AC pulling out the humidity as it normally would and not worrying about it. From the sound of it, they're talking about pulling in .4ACH of 85% (though I think that was specifically talking about temp, not humidity) pre-dehumidified airflow. It's a bit of additional humidity, but I doubt the AC would have any issues handling that, especially if the AC was designed to run in a house that didn't have an ERV to begin with. EDIT: Just remembered the AC won't be working very hard in this house, so he might be tacking on a dehumidifier in some future video. The more I think about it, the less I'm sure.

[@SpudsMcCat]

He said that it'd be within 60% delta of the outgoing humidity

[@kadmow]

@@ArthurDentZaphodBeeb : However this system could be feeding the dehumidifier / AC train with fresh "reduced humidity air" - meaning ducted HVAC with only one set of ducts to living spaces. Matt was showing off a dehumidifier with fresh makeup air not long ago - This would be a fit for that system - cobble this method of duct manifolds and regulation, and it would be approaching an ideal system. Even 85% humidity exchange efficiency is increasing the humidity in the house air by a % (not really 15 most likely, but significant. - and also the temperature inefficiency % is increasing Heating and cooling costs by that much. Obviously any similar type system (yes "this" is unique in North America) is much better than either a sealed tight envelope with no ventilation, or an open window.

[@pfguo87]

Is the Zehnder vent system not connected with the Mitsubishi Air Conditioning/Heat system? Can you do a video on how this all comes together please, Thanks.

[@douglasjohnson8917]

How does the system handle dryer exhaust? I currently have two lint traps on my dryer exhaust and I still get lint getting past the second trap.

[@regahj]

The system vents from the dryer room, not the dryer.

[@kadmow]

Put a HEPA filter in the dryer flue and all problems go away - just clean it regularly.

[@nordlands8798]

Probably best to get a heat pump dryer, then all of the lint is caught in internal filter at the door and most of the moisture condensed to a drain connection.

[@kadmow]

@@nordlands8798 . Condensing dryers have not been popular in warm places (in my exp) - as the premium price over a non condensing unit for no additional benefit -proviso- you/one can vent the moisture outside. If "Code" limited maximum number of "envelope penetrations" -or monetised (penalties) bad construction methods then choice of appliance type could be weaponised in the push for "PassivHaus" /"ZeroNet" (kidding)

[@nordlands8798]

kadmow Sure the heat generated could be more of an issue if you need AC, but with heat pump dryers it is not that much really. As more people buy them they also get cheaper, here the heat is no issue most of the year so almost all dryers are condensing, and now even most mainstream models have heat pump.

[@josephlownes5138]

How often do you have to change the filter

[@jodyboehs4545]

My folks-in-law have a system that is similar to this only on a smaller scale. It does not pull enough exhaust out of the bathrooms. The mirrors always fog up after a shower and I hate that. Wish there was a way to pipe in a regular bathroom exhaust fan into a system like this. Or be able to adjust cfm in each room especially bathrooms separately. I love the concept but I wish it pulled more cfm out of bathrooms.

[@dsdragoon]

Someday I would love to have a new tight house with a system like that. I'm tired of the dust in the house, no matter how often I change the a/c filter, and fresh air in the toilet room.

[@BrianKrahmer]

you will always get dust in your house. a majority of dust comes from you, not the outdoors.

[@zack9912000]

I never want a house like that, I maintain these systems for rich people and they are extremely expensive to install, maintain to keep them working correctly. People will never make the money they spent on it in energy savings as the market bs says period. They will cost triple over its life span the a medium range systems and a home with some leaking.