Zehnder ERV - 2 years Later at My House- Worth it

2 years later, Matt reviews his Zehnder unit he had installed at his home.
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[@TechnoCraftGaming]

"A smart home needs a smart homeowner" Very true

[@JeremyJohnson79]

Thank you for not cutting this one short. Lots of extremely good information!

[@robertbryan6189]

I wanted to see the core get cleaned. Good video.

[@fchiefe]

Thank you for your channel! You've given me confidence understanding building science and whats important with my parents' project to downsize homes. Our construction starts next week!

[@markstipulkoski1389]

What a great attic! Even after holding all that air handling equipment, you still have room to store some Christmas wrapping paper.🎄🎅🎁

[@superspeeder]

Two dedicated humidifiers and still high humidity? You need to plumb that Zehnder air through one of those dehumidifiers, Matt. You’ll save a lot of energy dehumidifying at the source (humid incoming air) rather than the mixed indoor air. For the price, Zehnder should be offering that feature built-in.

[@mkkd85]

Or use an HRV instead..

[@superspeeder]

@@mkkd85 in an air conditioned house in a hot humid climate, an HRV will bring more moisture into the house than an ERV will.

[@superspeeder]

Exactly. There are few places in North America where an HRV makes sense. If you don’t know, you probably want an ERV.

[@ericscott3997]

Matt stated in the video that he was running the systems fan higher to push more CFM's through the home. Doing this causes the ERV core to absorb less moisture from the outside (and inside) pushing humid air throughout the home. He also stated he bumped the lower dehumidifier up from a 70 to a 90, but didn't say when or how long he had that bigger system. From my time living in Georgia, I'd have spec'd my dehumidifiers bigger to begin with.

[@sdhlaw1]

All your shows are good. This one is EXCELLENT!

[@pennguino9137]

Wow! 2 years already. Thank you for everything I have learned about building science. Hopefully my funds will be enough to employee all of these lessons on my final Toe Tag home.

[@alantittle299]

Hahaha. Toe Tag. Pretty much my ambition for my pending build in east Texas Piney Woods, with probably more humidity. Despite our mold issues and knowing we should manage to 40 to 55% humidity for comfort and health these issues would have partially escaped my attention. I will have great living space with a view and a prevailing breeze passing over a lake so my ambient humidity will go up more. We need to think of the “living system of building science”.

[@pennguino9137]

That Radon exchange was eye opening. Just by not having make up air for it to suck that Radon up into the house. You have to assume his house does not have a barrier membrane under the slab/crawl space.

[@scottrodman4017]

Many thanks Matt, Sean, and Szabi for that information. Szabi just commissioned our Zehnder units and I am excited to be moving in soon to enjoy a new experience of truly clean air. What a great experience it has been working with Szabi and Charlie for our project, Build Show Boston. This video reminded me of the important service needs and timing for our Zehnder units. Now on the calendar! As always Matt, your content makes a huge difference and has encouraged so many people to take our own steps forward.

[@colinstu]

28:01 the fact that Matt mentioned that his house was set to be slightly over-ventilated + the fact this wasn't running in Low/slow mode, makes me think that maybe that's partially/fully responsible for the slightly higher humidity levels. Esp considering he's in TX.

[@wjthehomebuilder]

I can't believe it's been 2 years already!

[@dosadoodle]

I really appreciated this video -- great tips! We're doing mini-splits + Zehnder as part of our renovation of a 100 year old home. The overall costs of this setup is very marginally more than a similar heat pump ducted system with a lower priced air exchanger (which would also be less efficient). For instance, we were quoted at a $5k difference on mini-split vs a ducted heat pump system. We also are happy to not give up any square footage for ducting and such, because the Zehnder ducts are able to fit in 3.5" stud walls and so don't require their own space. Whenever we can save square footage, I translate that into the value of the square footage, so our setup also is basically adding $2000-ish in value / space. Being in MN, I'm also eager to get as much efficiency as possible, and during the coldest months, my back-of-envelope calculations suggest we'll save $25-40 per month thanks to 90% efficiency vs 60% efficiency, and that'll translate to about $150 saved over the winter season.

[@andrewfisher8749]

This why I’m in SoCal

[@kylepeavy]

That was an awesome video! Glad you didn't cut it short.

[@petersallay5221]

We had the same experience with our ERV in the dead of summer. The humidity would creep up and I would have to ramp down the ERV. Then the CO2 would go up! Finally we installed a second dehumidifier which was over sized to make sure we could keep our indoor humidity at 45%. We definitely enjoy the indoor air quality but what percentage of homeowners can afford this? We invested in the equipment because we had the knowledge from you and others. We made it a priority. Most homeowners have no clue about IAQ. If the topic is brought to their attention they typically balk at the cost.

[@boeing757pilot]

That was my question.. Do you mind sharing costs? I live in an area that has LOW humidity.

[@andrewfisher8749]

100 %

[@rickylabrecque7160]

@@boeing757pilot your looking at $12-$15k for a zhender system

[@greennixon00]

You never opened the core to see the inside!

[@DeuceDeuceBravo]

Bought a couple air quality monitors recently. Shocking info. Our radon tested fine when we bought the house, but pressure changes cause it to rise significantly. We were also amazed at the CO2 levels generated by two people and a large dog. The PM2.5 spikes to unhealthy levels whenever we are cooking. The house is roughly 1500sf ranch from the 70's but it's relatively well sealed considering its age. I'm trying to figure out how i can retrofit an ERV to alleviate these issues. So if you buy an air quality monitor (and you should!) then be prepared for nasty surprises.

[@todd5963]

What kind of monitor did you get? Don't send a link or they'll think you are spam. I'm considering a new one but want to get a good one.

[@DeuceDeuceBravo]

@@todd5963 I got a couple different ones... Airthings which does basically everything, and the Aranet4 which is smaller and more portable but doesn't measure all the stuff that the Airthings does.

[@colinstu]

@@todd5963 yeah I'm curious as well

[@thatguy7705]

The AirThings line is pretty good. You can connect them to the internet and track trends. Some of them can talk to one another too. I have a “View Plus” model and I’ve configured it to display the radon & CO2 levels.

[@todd5963]

@@thatguy7705 That does look like a nice one, that is what I was looking for. Thx! Onsale for black Fri, bonus!

[@andrewfisher8749]

Coming from California but was born and spent much time in the South, dehumidification seems paramount.

[@andybrooke1961]

Great video Matt

[@ilickspam]

if you're using hvac units that run low fan speed constantly, why not connect the erv to the dehumidifier first? then dump dehumidified fresh air into the supply plenum? they can still go through all the filter boxes. genuine curiosity

[@robertwalter2841]

Excellent, Just that simple! Thanks

[@kenbode8806]

Great episode, thank you for sharing!

[@billcunninghame8554]

Very informative video. If I'm ever in the position of building or remodeling a home, I'd definitely add a Zehnder ERV. It would be great if they added a sensor that detects when the intake or outtake filters need to be changed vs. a set number of days and notifies the resident.

[@bastiat691]

Sounds like the 6 month mark is in Switzerland where the air is clean :D

[@tullgutten]

I only have a diy system in my 50's ld house that im renovating and it is a medium large HRV from China and it works great. It is controlled on demand by 2 seperate Co2 sensors, 3 VOC sensors, 4 temperature and humidity sensors, and one dust/PM2.5 sensor. The air quality in my house compared to a friend with a 2014 house so much better than his constant low system. I did probably go twice the size i needed so it's most of the time off and only low speed. Never had stuffy nose, itchy eyes or bad smell innside ever since i got it Only wish it was ERV instead of HRV core

[@jamesphillips2285]

Did not know there was a difference between the two: so looked up the difference. From natural-resources Canada: "During the heating season, the HRV captures heat from the stale air leaving your house, and uses it to preheat the fresh air coming into your house. Similarly, an HRV can reverse this process during the cooling season, removing some of the heat from the incoming air and transferring it to the outgoing air." "An ERV can give you more control over moisture levels in your home during warm and humid weather, by keeping excess moisture out of your home. ... If your winter climate is extremely dry, ERVs recover some of the moisture that would leave your house through a regular HRV."

[@walnutcontractors5661]

What is the brand? Biggest thing with zehnder is the efficiency of the core for heat exchange. what is yours rated at?

[@Coleen_West]

Interesting! -- QUESTION -- Matt, there are some interesting medical stuudies emerging on "mineral wool" insulation and it has some cause of concern. That circular EXIT filter in the attic (behind the cardboard) seemed to have Rockwool coloring in it. ALSO, the top of your large silver ducts have dust that looks exactly like Rockwool particles. Just do a safety test on that filter and see if there are Rockwool particles in it - I suspect that it is. If so, cover up all the rockwool in your atic behind drywall or poly barier - in fact, do it either way as this is a real issue - love Rockwool but it MUST be covered and sealed perfect. You cannot get that out of your lungs if it is. You may be in danger so take steps.

[@MrBrianDuga]

Do you have a link to these studies?

[@Coleen_West]

@@MrBrianDuga ..there are lots of studies. It looks like it will have similar effects on lung / cancer incidence to asbestos as it is essentially a product substitute. QUOTE: "Based on these studies, the International Agency for Research on Cancer (IARC) classifies RW as group 3: limited or immature carcinogenicity in animals, and unclassifiable carcinogenicity in humans" Simply google "mineral wool rockwool lung cancer". California recognizes it as a Group 3 carcinogin (carcinogin means something that causes cancer). The problem is these materials NEVER get disolved by the lungs - they stay there forever and inflame and infect the cells and the inflamation, over years, causes cancer in the cells. (normal dust does get absorbed and passed out the system). DO NOT BREAT THAT STUFF IN. If you do use RW in a house, make sure it is sealed perfectly (but history shows that you can't seal it properly). Really, as much as I love that stuff, just use closed cell spray foam and be done with it. Too risky and history shows that it, RW, always always finds a way to become airborne and escape. Just the air pressure in that house could make that dust airborne. There are sings all over the attic of just that. Those filters don't have brake dust - they have Rockwool dust imo - same color and same fine dust look. Certainly test that exit filter and see. Plus all that dust on top of the large ducts has RW dust that fell on it from above.

[@raymondpeters9186]

Nice!!

[@HAVENIAQ]

Brilliant video 👏the 29 min soundbite from Sean is 😙👌

[@wink9970]

Nice video and lots of needed knowledge transfer.....

[@steven7650]

Zehnder europe has a model with dehumidification. Unfortunately they can't bring it to the US yet because of the energy penalty running dehumidification.

[@vahidtaeed665]

30:10 - "I've also learned, on two stories houses I don't ever try and heat and cool a two story house with one system. I also don't dehumidify a two story house with one system". Can you unpack this statement, maybe with a video? Basically balancing floors with one system in a seasonal environment vs separate systems for each floor. An important topic with very limited coverage online. I'd thought (hoped?) that passivhaus could get away with one central system given the limited loads and good mixing. Your statement seems to confirm this is not the case and that it is safer to have one system per floor.

[@matthewlacombe2146]

Why don’t they make an ERV and dehumidifier in one? The only one that I can find is CERV. It is crazy expensive. Also I live outside of Huntsville Alabama and need to get ERV and dehumidifier but it seems there are no installers around here. We are big DIYers, in fact we are building our own home so I’m ok with installing. We are using ductless mini splits so we can’t incorporate the system into our hvac. Thanks for all the info.

[@raymondpeters9186]

Fixing the humidity problem is easy to solve Just dehumidifi the incoming air Bury a 6" conduit 8' underground for incoming air When the hot moist air hits the cold conduit it will condensate before it gets to the ERV unit Take care Ray

[@walnutcontractors5661]

and then you have a pool of water sitting in the conduit. organics will be pulled into the conduit and mix with the water. mold will eat the organics and you'll dirty fresh air.

[@JeffreyMota]

Make this a series ( 2 year later ) worth it? Regrets? On wall compositions, material, Plumbing, electricity, windows doors, and so on all the details

[@Dmreeves1]

Interesting the size of the filters for a home with 45000 cubic feet of air VS the cabin Air filter on my Tesla with 120 cubic feet!!!

[@chrislambert4885]

Fascinating stuff. Would love to see more about how all of your environmental systems work together in your house. Also, is the ERV system you have only for new builds? Is there anything out there for retro fitting into older homes?

[@DrWarBear]

I know a lot of ERV manufacturers (probably Zehnder included) have installation options where you can plug the ERV into the existing HVAC ductwork (essentially the incoming make up air goes into the AC supply, gets conditioned and then goes into the home, and then the AC return has a small off shoot that pulls a small of air back to the ERV and that becomes the exhaust that leaves the house - if that makes sense). That may be an option for retrofit where you don’t have the luxury of installing dedicated ductwork for the ERV separate from the HVAC

[@dragon050417]

Love watching the channel. Wouldn't it be better to have 2 ventilation systems on a multilevel house as well?

[@steven7650]

@zehnder america, since the unit is internet connected, why not have it automatically look at the weather. It has humidity sensors, why not add an outdoor sensor that adjusts for the outdoor humidity?

[@rogerwhiting9310]

What would be a good stand alone air quality meter to put in my house NOW...to see what I have BEFORE anything else?

[@peteharvey207]

'tight is right' 😂

[@cszulu2000]

Is it better to have two units smaller ones rather than one big one with long ducts ?

[@ilickspam]

you personally need to clean each filter per exhaust as well? what happens if you dont have those filters per exhaust port? it's exhausting and going to the filter before the core anyway.

[@xiowolf3]

Would love an update on the water filter.

[@MerkDolf]

Feels strang comfortable tempture outside I've got the doors and windows open air moving through, and now thinking I'm goung th stop that and wse electricity to move the air through a folter and energy recovery system.

[@SlackerU]

I think it might be cheaper to just have the home ac thermometer in a hepa-filtered intake-room with a variable-speed high-pressure blower which would intake 15-CFM per person & possibly 55-cfm(or whatever) for the clothes-dryer, & 30 CFM for the stove-hood or bathroom vent... having it automatically intake filtered air with the needs of the home might be even more efficient than 24-hour mixing. The ac already distributes air.

[@TJ-22]

Do the majority of homes in the Houston area have humidity levels in the 60s?

[@VernBigDaddy]

Good thing you insulated over 2 years ago. That Mineral Wool would be impossible to get and you would pay big bucks for it today. Lead times on mineral wool batts are close to 200 days right now.

[@supersuper7610]

all the air in and out...on winter and summer is your HVAC running all time? and your energy bill high???

[@jonerlandson1956]

that is a great demonstration of how air quality can affect our health....

[@danielherman9483]

It doesn't look like Zehnder is readily available (least not as my local supply house) - looks like it would be extremely cost prohibitive to get one installed. Do you have any opinions on some of the more readily available brands like Panasonic, Fantech, Broan, or Aprilaire? I've seen you work with Panasonic and Broan in other videos, would be neat to hear your thoughts on what ones you'd choose for retrofit.

[@DeuceDeuceBravo]

Zehndwr is VERY expensive. The build quality is awesome but it's overkill for anyone on a budget (like 99% of us). All the brands you mentioned will do the same thing.

[@josephstevener7499]

Just for curiosity sakes what is your power bill each month to run all that equipment?

[@ritste1654]

Being close to an interstate, I lived next to I-4 in Orlando for a few years and dust is a nightmare. Could you install a prefilter in the duct going into the unit to help extend the life of the Zehnder filter, which I am sure is a bit more expensive than a cheap merv 4 or 6 standard size filter. Of course you have to consider that the flow of air is affected by the prefilter.

[@itsallwonky]

I've done some digging and Zehnder is the ONLY HRV system I can find that can be integrated into home automation. There is a LAN/network interface available and Home Assistant does have support for it. Mobile app support too. Or, if you want KNX you can control via that system.

[@js-wq6zy]

You could build your design which adds a pre-filter, ie a less expensive ....

[@boeing757pilot]

Great info! Im curious the yearly operating costs of this unit? How much power does this use? Thanks to anyone who can answer..

[@chipmhandle]

I still don’t think the Merv ratings are high enough! I hope you have other air purifiers in your home

[@mlchemwolf]

Could you fit a screen box for the air intake. To keep bugs out

[@tweake7175]

Why is the 2nd filter after the erv? Wouldn't it be better before so it keeps the erv clean and so you're not replacing the erv filters as much $$.

[@MrJramirex]

I'm sold... but the price is very prohibitive. The quote I got 2 years ago was roughly $12k for the unit and parts only. Can't even imagine what people pay for parts and labor to install a system like this.

[@StealthNinja4577]

So you'd get a heat exchanger, a dozen filters, several boxes, a bunch of ducts, and a cheap android phone... I can't imagine the cost to them is more than 500 in parts so you're paying for all the units they don't sell, Matt's ad, and everyone's salaries at the company.

[@davidscribbins9192]

Shouldn't you replace your erv core with a hrv core to save on use the the dehumidifiers ?

[@davidhoover2446]

Everyone talks code and theoretical cfm for ventilation. However, I always wish to see actual air quality data - PM2.5, TVOC, and C02 averages and see if it’s actually enough ventilation. The only one’s doing it are Build Equinox with their CERV2 ventilation which ramps up and down based on the pollutants present in the house. In my house, I just have fresh air and a dehumidifier dumping into my A/C return. With 2 adults and a child to see good air quality all the time I’m moving about 120CFM. I think once our family grows I’m going to have to upgrade because I’m at the most my dehumidifier can handle. To me, I would think 160 cfm is about right and with your size of family, I’d like to see actual calibrated VOC and C02 monitoring showing healthy levels (under 800 C02 and 125 ppb average TVOC).

[@zenrook1]

33:42 “Our house has 0.14 ACH” Wow that is crazy low. Matt’s house is 0.60 ACH 50.

[@morganoverstreet6824]

Matt- assuming my house is between 3 and 5 ACH50 is there even a need for an ERV at all?

[@peterdeluca6516]

I find it hilarious that Zehnder doesn't publish actual performance data (core efficiency) at various flow rates like all other manufacturers do. The only single datapoint I can find is "up to >90% in the HRV". The Zehnder rep "accidentally" mentions that the efficiency drops as the flowrate increases. How can you say you are the most efficient and "best" if you won't publish the efficiency of your core to compare against other brands? I did a lot of research and am going with a Renewaire Premium L,which is above 81% efficient for ~120cfm flow (and 88% efficient at 59cfm). As with all things you see, always do your own research and compare, don't assume what you hear about "this is the most efficient" is accurate.

[@walnutcontractors5661]

Why would you put the comfo 320 filter box after the air has passed through the core? I suppose the idea here is that you've removed all the larger particles before the air enters the core and then you pass the air onto the MERV 15 filters. It wasn't clear what the filter stack was in the 320. you removed the 2 merv 15? filters with the yellow but it looked like there were some white prefilters? Thank you for the video! Beats reading the manual. I'll wait till you do a washing the core video before I wash my core - lol. Couldn't wait. Found a video though it misses setting the unit to service mode. kzbin.info/www/bejne/aJjOfJlsZZyesKc

[@luixmod1]

Matt your humidity problem I think is because you have a ERV, if you change to an HRV you could reduce your humidity. what ZEHNDER said?

[@afbigfish1]

The new Broan AI units look to be the ones to buy.

[@danielwoodard680]

great series. I have been watching these episodes several times with architects and builders for 5 years. I Could not hear the zehnder rep re his house. Please match volumes in off-mike conversations in future videos.

[@Actio83]

Can i just buy the ERV core?

[@RichsClub]

How much are one of these units going for?

[@harveypaxton1232]

How does this interact with a house with gas-fired appliances.

[@paulpoco22]

Can you reuse an old furnace exhaust(goes from 1st floor to 3 floors then out roof) as exhaust air for ERV or HRV? Already have fresh air intake but only 4" and don't want to punch another hole in the wall.

[@MorryB]

There are also dual ported (tandem) inlet/outlet fittings that allow you to use a single hole for an HRV. 4" might be a bit small for these however.

[@mitchdenner9743]

I'd like to know the effect on static pressure that secondary merv 15 filter box has on the system.

[@apex007]

It was clearly designed around that filter. Why are u concerned?

[@blt981]

Can you explain with the system I don’t know what it is…

[@johnzach2057]

Matt for the love of God, you have the money. Install an activated carbon filter. They will only help.

[@nedunonnyp704]

I Wonder How Much those Filters Cost.. ?? And You Probably Can Only Get Them from Zehnder.. ?? 🤔🤔

[@clinta746]

I keep wondering if this type of system is appropriate in a house in the far north that does not have AC or dehmidification. We spend summer with the windows open. But in the winter it would be very beneficial to be able to bring in fresh air without losing heat. Do we still need an ERV? Or is an HRV more appropriate?

[@StealthNinja4577]

I mean with a Honda HRV you can at least go places in it

[@woodlyz]

We just build a new house with a 1.05 blower door. We added an hrv for ventilation due to the need to keep the humidity lower in the winter time.

[@rocky7gd]

After 2 years a sensor gone bad already?

[@flynjay7178]

Tight houses should have heat pump dryers.

[@jamesphillips2285]

8:45 Would be better if the system supported Home Assistant integration, allowing the user to program that themselves. Edit: they let the user change that in the menu on the machine.

[@itsallwonky]

There is a network interface available and Home Assistant does have support for it. Mobile app support too. Or, if you want KNX you can control via that system. I've done some digging and this is the ONLY HRV system I can find that can be integrated into home automation.

[@jonerlandson1956]

the pipe tunnel...

[@pleka]

"I want to get your unfiltered comment..." nice

[@Thee-AmateurAn94]

BUIIIILLDDD SHOOOOWW LESSSSSSSSS GOOOOOOO 💪🏽🫡

[@steveksi]

Nice. Unfortunately most builders are just very basic. And quality on normal stuff leaves a lot to be desired. You do a great job. Cost is always an issue. Making things like this code is the only way the masses can get top quality environments to live in.

[@StealthNinja4577]

So not only do I have to hit this unit up every 6ish months but I gotta run around to every room and clean another filter in each one... I really think you should wear a full face mask at minimum when you're outside if not a hazmat suit or some bubble iron lung combo. I remember when hypochondriacs weren't obsessing over the air they breath to this extent

[@MorryB]

Matt has filters for his filter's filter!

[@JeremySpidle]

Smoke 'em if ya got 'em!

[@gsantee]

Nasa taking notes for a friend.

[@ABC-wz2db]

Need more nerd.

[@JeremySpidle]

Those are some TINY filters, Zehnder... bet they want $50 apiece too?

[@MerkDolf]

Now if they only came with their own solar system and 10 day battery back up.

[@tristanwegner]

a lot of talk about cleaning the core, but no core cleaning

[@Thee-AmateurAn94]

Instead of inhaling these debris in small amounts over time you inhale them in concentrated amounts all at once while changing filter. 🤔

[@MerkDolf]

😀 👍👌.?.

[@jamesoncross7494]

What happens if the grid goes down long term?

[@4himsanctified]

mad max

[@mrstinky2421]

Generator

[@DeuceDeuceBravo]

What's "long term"? And what is your concern with a power outage?

[@MorryB]

You....open the windows! :O

[@apex007]

You die from farts not being able to escape the house

[@Omnis2]

If you live in south Florida and put an ERV in your home, all you'd be doing is blowing in all the neighbors' weed smoke. It's awful here.

[@markrice3019]

🤣 🤧

[@markrice3019]

🥳 🤠

[@iandouglas4992]

Spend enormous money to insulate the crap out of the house to the point you need makeup air, and gas stoves become an issue due to no drafts. Etc etc. Seems like it's not worth it longterm

[@publicmail2]

We will start to see sick people in these air tight homes, because they won't maintain these units or they will break.

[@benzun9600]

super cool system, but maintenance what a pain. I built a new home well insulated well ventilated. NO AC NO CENTRAL HEAT. We just heat with cove heating in bedrooms and gas and wood in master and living area. Very little maintenance.

[@dlg5485]

Changing a couple filers 2x per year and washing the core every 2 years is too much for you?

[@greennixon00]

First