Hey thanks buddy! Will do.

I could use some information about reducing indoor mold spores. What is the name of your company? Do you have any suggestions?

Hey thanks my friend- glad it might help

Thanks!

Thanks Al, got it on the list

@@HomePerformance Yes please! Also, where are the supplies?

Either bedrooms, or dump it all into the central duct return

@@HomePerformance Wouldn't ducting into the return throw a lot of new , moist air (from the outside) into the unit, vs into the supply and letting it get comingled with other, already dehumidifier air and then sucked back through the normal returns?

@@HomePerformanceisn’t it a bit more nuanced, exactly the way you discussed flow through the bathroom, you’ll want to ensure that all the living spaces have good air flow? I’m referring to dedicated supplies.

Thanks Mark

Thursday’s video will hit home for you, Robert- but short answer is that will not work in many cases. Depressurization sensitivity is the issue once you get airtight enough.

Thanks

Hell yeah man

I second it. Controls are not well understood but are necessary to any successful ventilation strategy

I love the Cerv2 we put into our office and I'll be ordering another for my house and I'm in a similar boat to what you've said above. The only thing, if I may, I would consider adding would be a zone damper and put your bathrooms on that zone and then you have a second zone with everything else. What you've described is what I originally planned, but after using the Cerv2 unit at our office now for a prolonged time, I would definitely only want the bathrooms to be pulled from if the unit wasn't in recirc mode. This thing is super smart and does an amazing job... I'm adding the outdoor sensor actively as there is one event happening every day at a certain time that seemingly is coming from outside the building... Someone I never would have known or paid attention to. I love the Cerv2 and will be coupling it with a heat pump unit at some point in my setup that will cover the majority of the load. In any case, I am not being critical at all of what you said, but this is something I had to adjust after using the Cerv unit for a while so I thought I'd share my speed bump. Edit: I thought I would mention/remind that the system you always hear people talk about generally has the replaceable core vs our much more programmable heat pump system. So we don't have anything to replace, but our air streams work differently .. that's the reason I mention the above and the video goes against what I said... The core exchanges much of that energy and exhausts the rest... Ours very well might be simply recirculating depending on the outside air variables.

One thing I noted from your current setup is that your dehumidifier supply puts its dry air into your HVAC return. This isnt ideal since you've removed your A/C's opportunity to dehumidify. Also, I think you mentioned your dehumidifier is always on. This will push air over your cool/wet a/c coils drying them thus pushing water back into your home. I found it counterintuitive but it's fine to add a little more static pressure to your supply (in most cases). Hope this helps

@@DonovanSexton so some sneaky dude is taking a stinky dump every day and it's smelling up the house? Or are they smoking up outside? Sorry I couldn't tell. CERV2 is so cool. Tye is the man. Maybe zone dampers are the way to go.

Good point, Don- the Broan and Zehnder ERVs both have recirc modes that would need to be disabled in those scenarios

@@DarenSpinelle Not exactly. The evap coil will be removing less latent heat (moisture) from the drier air so an added benefit is that the a/c can be down size due to a smaller total cooling load.

I happen to know from experience it is enough, I’ve lived with ERVs for seven years in two homes. What 360 are you referring to? That’s not a residential sized unit. Also, what emergencies are you imagining?

@@HomePerformance my dog's create some emergencies from time to time

Cleaning is not optional, of course

Open a window, Koo Koo. You are so cute when you’re serious. Simply, adorable

You are not alone my friend- many of our viewers and clients are the most savvy people in their entire town. Like you, they all have to push their builders and subcontractors to do new and better things. Thanks very much for watching, happy we're helping you with your project. Try these resources: homediagnosis.tv/pro maineindoorair.org/member-directory/ Best of luck!

Ugggg I FEEL YOU~! 🥴

Thanks Sebastian, and as long as you test the flows you can dial in whatever CFM you want. AH distribution means you get an immediate second filtration on the incoming air, and you already have a duct system to deliver everywhere.

Heat/cool grille decisions are governed by the Manual J calc.

Thanks man, happy to hear it

Sorry Doug, no advice from me, I’m not a hydronics guy. House sounds prettt good, just make sure the garage has no air connection with the house when you blower door test (using a zonal pressure test).

splits will condition the air and remove some moisture however you still need to exchange the air otherwise co2 will build up and other pollutants. With a good temperature exchanger in the HRV/ERV, the temperature of the conditioned air should be retained to a large extent.

if your running mini splits then you need exhaust/supply ventilation in every room. thats exactly what i have in my home.

@@bevthebuilder5457 “Should be” is a statement of hope. That’s not how physics works. Assuming a variable capacity system can “control” the temperature and heat energy in the air is a fundamental misunderstanding of Psychrometrics. Furthermore, it’s all about a given manufacturer’s testing and performance capacity tables being available for scrutiny and after installation commissioning. If you can’t predict it, why do it.

More ideally, each room would have a center ceiling supply, and exhaust at opposing walls near the floor. This provides clean laminar air flow to the head, pushing floor dust into the exhaust.

Every room that has closable doors needs to have its own balanced supply and exhaust. If the supply and exhaust to a given space are separated by a door, then when the door is shut either you have a draught under the door, or there isn't a big enough gap for a draught and the airflow simply stops.

I don't see why not.

I was wondering the same thing about the ERV connecting into the return of the air handler. Often air handlers in the high efficiency homes don’t run as often. So would think the ERV connected to the return would require the air handler to be running all the time with the ERV. Or the ERV would need to connect to the supply side of the air handler.

@@UserError7861 Yes the main air handler would run whenever the ERV was running. The trade-off is not having to install separate supply ducts from the ERV.

Great question, but an ERV of any brand at all does not 'combat' in my mind, it just resists. Depending on how airtight your home is, the wind may have even more ventilation effect on the home than the ERV does.

you could just use a single exhaust vent for the ERV in the centre of the house (some brands here promote that), but then you still need bath room fans etc. so why not just use it to your advantage. you need to have the exhaust so might as well make it be a bit more useful. having constant airflow going through the bathroom is great. no need to have a separate bath fan.

@@tweake7175 Yeah, I'm not referring to the outside exhaust necessarily. I'm referring to using the cold air return vents that are already in most of the rooms to take the air back to the ERV, instead of running return air ducts to the HVAC system and separate return tubes to the ERV. It seems like a lot of extraneous duct work and extra expense when, logically, you should be able to use the same ductwork for both systems.

@@r.j.bedore9884 yes. Most just use the hvac system to ventilate.

If you dump the fresh air into the return side then yes. If into the supply side then no.

Think of a centralised HRV/ERV as being a sealed and balanced system. A standard bath fan that is exhausting externally will unbalance the system when turned on and cause short circuiting (ie the return will draw from the bath fan rather than the supply) when off.

Thinking same. With erv, humidity in shower would be redistributed to entire house.

End of the day did not pursue using the ERV as bathroom exhaust as that was against code.

@BenNC22 it is not against code. It is built into the Int’l Mech Code.

@@HomePerformance it is where I am. Multiple code officials in my county and hvac pros stated definitely bath exhaust must be directly vented outside. ERV was specifically not allowed.

@BenNC22 I believe they misunderstand ERVs, or their own code, or probably both. You can always appeal for an exception.

Can work, just missing the extra filtration. Maybe best would be a Wye with an either/or damper.

Do a blower door test- only way to know for sure

Mythbusting ERV vs. HRV: Which Ventilation is Safer for Moisture and Humidity? kzfaq.info/get/bejne/h7WVZ8-d2q3bc5s.html And the kitchen exhaust is absolutely necessary, but should have absolutely nothing to do with the ERV.

Then this: HVAC Reality Check: Are Duct Systems Dumb or Essential? kzfaq.info/get/bejne/a7yApKmErrrRYKs.html

Winter humidity is actually super dry when you warm that air up to room temp. See here: Humidity Control 101: Psychrometric Wheel Calculator’s Dewpoint and Grains/Pound of Moisture kzfaq.info/get/bejne/qZOGrNSVvtSploE.html

Always need an exhaust hood going outdoors over the cooktop

@@HomePerformance Yes, agree. Do you recommend both an ERV return and supply in a large open kitchen/great room?

@TheGhussey neither at my house, unneeded- but there are no wrong answers

A register with a closable damper on it would work, but you'd have to be on top of opening it again or you'd get moisture issues in the room.

In a well-designed home with the right equipment installed, you’re able to do things like this without big consequences, as long as you know how to make the system work for you.

Sir, this is a design decision, if you want a steam room to double as a restroom, then so be it. It’s your castle. I think you are asking the right questions. And remember, controls are a key to automation. So that closable damper can be on a sensor. Just sayin. Keep a healthy distance from zealots. They smell funny.

If there’s no door or curtain, yes

I would ignore the closet

I thought he was saying that some folks are paranoid about the laundry room being dirty but he is not. You're right though it does exhaust itself sometimes.

I like this discussion. I think, having years of commerical (large volume) and custom home ERV experience, that some people want to believe that ERV’s are magic. That an ERV can somehow perform double or triple duty to address a multitude of IAQ and building pressurization concerns. It is one of many tools in the toolbox. I would not advise to move air into or out of a closet or laundry room. Moreover, making those suggestions can be dangerous at worst, reckless at least. Anybody hear of combustion air or door undercuts?

Not climate, but home characteristics- if your home is tight enough that bath exhaust fans will cause suction problems, you must have an ERV to exhaust from bathrooms and balance. If not tight enough for that, then stick with simpler means of getting fresh air. Watch this: kzfaq.info/get/bejne/otR_dqSBtby4ZZs.htmlsi=yRBsI7JJ7y2h8Heu

@@HomePerformance ph, let me clarify. I mean ERV vs supply only systems. MY point is, I think in Auckland it's not worth the extra cost to try and recover heat from the exhaust air.

Again, I don’t even worry about the recovery aspect- to me, it’s all about the balanced pressure in the home.

There should be a powerful exhaust fan over the cooktop, dumping outside. If you have that, whether or not there’s a 25 or 40 cfm ERV exhaust in the space is not a big deal.

@@HomePerformance So you are not against having an ERV exhaust in the kitchen!? It’s just if you have proper exhaust over the range with a proper makeup air system there is no need for it!

Exactly right

Depends on air tightness. It’s not an issue in a leaky home. Tighten things up and mostly your options are: add dedicated passive makeup air on a pressure switch, buy a heat pump dryer (best option for energy), or find another way to get air inside. For instance, Lunos ductless HRV fans allow about 35 cfm each as a passive makeup air mode. The fan turns off when it senses the pressure difference (I called the US rep, 475, to find out). That’s 140 cfm with four fans, about enough for a dryer. I have seen reports of new ducted HRVs that will ramp up exhaust when they sense a makeup air demand.

buy the heat pump dryer, you wont regret it.

@@bevthebuilder5457 which one? Miele models are too tiny for the average American consumer

FYI, Connor, the Lunos isn’t one of my recs because it doesn’t set up a consistent pressure imbalance. So you’d still have to use bath fans, which in airtight homes is a nono.

Disagree on the tiny thing- it holds 17 lb wet I think- efficiency of form helps. Also, the Miele washer it pairs with spins faster than any other residential dryer, so the clothes start drier to begin with.

Weirdly worded question bro

Zehnder is undisputably the most expensive and elaborate dilution system you can find, and you can’t combine it with other equip like a dehu. Not my choice because I like to play with HVAC like Legos. Zehnder is a brand that doesn’t lock in with the Legos.

@@HomePerformance Hmmm can you explain this in more detail please. Zehnder doesn't dehumidify but they say you can a dehumidifier and have it part of the system. Then a make up air system for a hood vent is separate. Also in this video you show only so much exhaust going out what about all the air needed for the number of people that may come in such as a party of 10? would you not need more air and what comes in must go out?

Exactly, Larry- filter grilles are only for not using the return for anything else. Filter slot is so much more versatile. Also, 0.5 would be supply + return, so ideally you only have 0.1”wc in the return trunk.

@@HomePerformance I will check where and how large that pressure drop appears soon. I suspect that making the filter location change is in order. Being in the attic, makes it not such a fun chore to change the location by adding the filter box at the inlet. I have been also trying to decide if I can economically change the blower motor to be more efficient (EC or DC) such that i can run it at 1/2 speed in fan / heat mode with 1/8 the power while the ERV is active 25% to 100% of the time vs drawing 400W all day and making more noise than is desirable due to the air velocity being a bit higher than needed.

Thx Eric

YES, which is why I advocate ducting the fresh air into the return of the central air handler- it'll get there. Otherwise, a totally separate duct system is required to deliver it to each bedroom and office.

@@HomePerformance so, the returns from baths and closets get fed into ERV, fresh air from outside also gets fed into ERV... ERV transfers the energy (hot or cold) from baths and closets to fresh air from outside.. and this outside air, now with energy transferred to it gets fed as the return to the home HVAC system..... Will the HVAC be able to appreciate/ detect the return air temp and adjust itself ?

@@jimmyphilip2340 I wouldn't think so. Maybe some types.

@@jimmyphilip2340 No. The frest air is tempered and mixing with the room temp air circulating in the return duct. The blended air will eventually change the temperature at the thermostat.

Use an air mixing cslculator online to see how little impact it has.

GREASY AND BURSTY!!! I love it, using that from now on. But yes.

Are you familiar with Minotair HRV which has a built in heat pump? The unit exchanges air, dehumidifies, heats & cools, and supports Merv15 filters. Would be interesting to get a video on some these smarter ERV/HRV units like CERV or Minotair

Dump it near the minisplit, then it’ll get grabbed and distributed with the bigger airflow

Yes, that’s my recommended way, Skyler

There are two airstreams with four connections. One must be exhausted to the atmosphere if the conditioned air (intake) is sourced from the restroom. Generally, an ERV is strictly used to temper the fresh air stream (ventilation air) by reusing the conditioned air (intake) to minimize any temperature change within the space. That is it in a nutshell.

I’m assuming the kitchen would have a separate exhaust with high cfm and separate make up air system. But you make a good point. Given the proximity lingering odors and other vocs when not cooking would naturally be pulled into the master. I wish Corbett would address this.

Bedrooms are positive pressure zones, bathrooms neg pressure. When cooking, the kitchen becomes neg pressure zone because of the massive exhaust hood with dedicated make up air (400 cfm, 2.7 times more powerful than the ERV).

The intention with all ventilation strategies is to dilute the breathable air, not scrub it. ERVs are generally designed for Class 1 air. FYI - It would be best to post a comment of this nature in a form of a question. That way you don’t sound like a neophyte. Cheers!

​@@HomePerformancewouldn't it be more efficient and effective if you run the air from the kitchen exhaust hood through a whole house dehumidifier, which takes the fresh air from the inlet of the ERV/HRV equipment? That way you are keeping the building envelope closed.

We’re all always learning

We seem to be approaching the end stage of overly complex societies. Shouldn't be long, before we are back to radio communications and out houses.

Only some manufacturers test for that, and probably not all of them list it if they're not happy with the results. Broan does, and Renewaire too I believe. You should spec a dehumidifier, I almost guarantee the ventilation will increase your home's humidity levels.

@@HomePerformance I already have both. Massive humidity issues... Working on iterating after 6 years of problems. - Builder Install: Unfiltered passive intake into unfiltered air handlers. Filter back grills. - Rev 1: Capped one wall penetration, UltraAire 120V ventilating dehu on the open intake ducted into air handlers, SantaFe Classic in Garage below home, five 70 pint retail dehumidifiers around house. - Planned Rev 2: Dual UltraAire 70's and a Broan ai ERV all ducted into air handlers, SantaFe Classic in Garage below home. Unfortunately at this point I'm stuck retrofitting for damage control. Targeting < 50%rh.

@@jongosling4870 check your building envelope with a blower door test.

Damn Jon, that sounds intense. I agree, blower door test might be in order.

@@HomePerformance "someone else's" blower door expert gave me a 5.

They’re positive pressure zones, which encourages circulation between rooms.

Int’l Mech Code. 20 cfm for bathrooms.

Because I’ve done it, Dragon- in our forever home. Ducted it myself with hard pipe, and I can attest that the benefits do not outweigh the costs.

Part of the issue is joist space real estate. In a normal 3000 ft² bungalow, you'll have around 25-30 sheet metal supply runs, some of which can share a joist with each other, most will be on their own in a joist running one way or another. You'll have 5-9 return airs usually - those take up a joist space each and can't, or shouldn't, share the space with anything else, especially plumbing, and definitely not metal. Another joist is lost to the venting for the furnace, and usually the hot water tank will take one as well. Plumbing will be coming down and traveling towards the main stack from all the bathrooms, kitchen, etc. If there's plumbing in a joist cavity, you can only usually get one sheet metal run in, meaning another goes elsewhere. Every single thing I just wrote is determined my the orientation of the walls on the main floor, and has to take in account getting things to code (sheet metal supply runs terminating within 4' of the exterior wall, and really they never get that far out, plus returns being unobstructed and proper pathed out, also clearances for venting). ERVs exhausts and intakes also need clearances. In Ontario Canada, and mostly standard elsewhere, fresh air intakes need to be 10' away from any exhaust. With how cramped the basement sounds based on what I just wrote, adding a doubled up sheet metal duct system, even if it's a bit smaller than a normal duct install, makes for a way more complex basement, wall system, cabinetry upstairs, framing and trim...it all adds up, and real estate can be the biggest commodity there is.

Forgot to mention in that that it's perfectly fine to just take out exhaust from the ductwork, and put fresh air in at the return side before the filter anyways. Saves space and time and the ductwork is going to all those places anyways, most of the time

@@levidobbin5654 wow thanks for the explanation but that's a bit discouraging. This is also why Zehnder seems appealing to me. I might not use all 12-15 of the lines they recommend but I feel the 4" flex pipes would find their way through that labyrinth, at least to supply the bedrooms and exhaust the bathrooms etc. My real problem is that my house is pretty big with 3 levels and I wanted to have zone control. I don't see how inline erv is compatible with that unless maybe I get a little erv for the two bedroom zones. Also wanted to tie dehumidifier in with erv. The local HVAC companies are not pleased.

@@HomePerformance Thanks Corbin. What should I do if I want to have zones?

Erv, being porous, might reintroduce Crack back into the house, along with bathroom farts.

This is about energy recovery- I think you’re looking for the channel on crack recovery.

If you want continuous fresh air, then, yes.

Yes you do, Fred- otherwise it won’t go through the filter, get mixed and conditioned, and get distributed through the supply ducts. It’d just turn the other direction and follow the path of least resistance out through the return grille.

@@HomePerformance Thanks for the timely response. That's what I expected, just being sure.

@@HomePerformance but if you had one way dampers fitted they would close when the hvac was off and air would be forced to go the correct way, or would that put to much restriction on it?

A one-way damper on a return would be massive, and for sure would increase your static pressure.

Sounds like he's recommending piping all supply into HVAC return before filter

Because the fan over the shower won’t pull odors from the toilet effectively.

@@HomePerformance got it. Thought it was for removing additional steam/vapor, but purely for odors, not necessarily required

Also, if you use the Broan AI to dump into your return, does the "AI" still work? Or do you need to manually adjust?

Nope, always separate. That will need its own make up air: kzfaq.info/get/bejne/ebmdqqd43drQeIk.html

Fantech MGE4 and MGS4

No, in my view it’s one or the other

Yep, it’s stated in the bid. Dump it into HVAC system or duct to bedrooms.

Never thru an ERV- too polluted, will clog the core. Watch this: How to Design, Install, and Test a Perfect Kitchen Exhaust and Make Up Air System kzfaq.info/get/bejne/mLObqaafltmrpp8.html

Thanks. I think I watched before. And I will do again

Overly humid house during winter with any ventilation system running is very unlikely- sounds like something is wrong in that case

You have a dedicated exhaust hood dumping outside, use that

But this way you make a messy disbalance of in/out volumes. Will not work in tight envelope houses. Good extraction hood can do hourly cfm of an erv/hrv in few minutes. And in cold climates this will not work, might freeze the unit as it sucks a lot of cold air and there is no exhaust to warm it. Better to do extraction hood with carbon filters, that dumps air back in the house and have erv/hrv exhaust in kitchen. Well at least thats how we do it Europe.

Check the ‘intermittent’ exhaust rate spec’d in your code. Otherwise easy to get an exemption if they have something lame like operable window exemption in there

@@HomePerformance Will do. Thx. How are you measuring and then air balancing for those low cfm's? Did you install dampers on each branch? Also, I'm a big fan of return air filter grills at each point of the system...similar to your central return. Inexpensive upgrade.

I’m glad you’re not dead too