Erv System

[65’Comet5.0]

Recently built a 20x40x10 garage with open ceiling roughly 16’ peak. Building is sprayed foams with 2” of closed cell foam on the walls and roof. I have a mini split system in the building maintain 68-72 degrees in there year round. Currently the building is very energy efficient so I’m trying to keep it that way as much as possible. Shop is usually empty all week I just go in it on weekends to mess around with my project car etc. Issue I’m having is the building is so air tight anything I spray in there or anything I spill a week later I can still smell it. This got me looking into erv systems.

Has anyone installed one in their building? Did it help? For exhaust I open the overhead door and use a fan so that helps but for small repairs I don’t want to smell it days later and loose all my energy efficiency.

For instance I did a disc brake conversion on my 65 and now almost two weeks later I can still smell gear oil and brake fluid in there. If I just go out there and look at something and come back in my wife has said she can smell the garage on me.

Of the residential models this looks to be the highest cfm one I can find so I was leaning this way, during the week I can set it to run a few minutes every hour but it does have a boost mode so on weekend when I’m out there and know I’m going to be working I can turn it up to max speed for the day.

https://www.supplyhouse.com/Fantech-ATMO200H-ATMO-Series-Fresh-Air-Appliance-Energy-Recovery-Ventilator-6-Side-Ports-191-CFM

 

[dcg9381]

Dad just finished a 6 car garage setup, living area above. Foam insulation. Full HRV system. The HRV is actually just upstairs and it's fully automatic. You set humidity control, etc.

I would not consider it a "get stuff out of the garage" system at all. The "simple" ERV systems I've had are just an "outside air" automatic valve that allowed that air into our HVAC system.

In our garage I installed an "attic fan" above the garage portion and set it to work via a switch or a thermostat. I assume the garage doors leak enough that we're able to pull in fresh air. The idea of this system was to "auto vent" the heat from cars when they get parked in the garage, so you're not heating up the living space above it. The air is exhausted out the holes in the soffit. For an application like you've got, this is probably what I'd just, just set the timer when done and walk away.

 

[MongoTA]

First, try to minimize the extent of the initial air contamination. I have an exhaust fan and flex duct system similar to but not a true welding removal setup, just a cobbled together one. I use it when welding and when able (not all situations allow it) when spraying volatiles. It really does help evacuate at the source.

Also consider adding an activated charcoal filter as a part of the existing air circulation system so when it is running, some filtration is occurring. Might help with latent fumes.

If you had issues with humidity, etc, then I'd consider the ERV. You may still need one. But just for volatiles, to start with, I'd look at carbon filtration. At least research. I do have to say for a very large volume/space it might not be feasible, so I'm just tossing out suggested ideas.

I'll be following this post though, as I'm interested in what the knowledgeable folk have to say.

 

[Jackfre]

You have to be careful asking a unit to do this type of work as it is not explosion proof. I think you should simply vent to the outside and pay the small energy penalty. As tightly as it is built it should recover quickly.

 

[65’Comet5.0]

First, try to minimize the extent of the initial air contamination. I have an exhaust fan and flex duct system similar to but not a true welding removal setup, just a cobbled together one. I use it when welding and when able (not all situations allow it) when spraying volatiles. It really does help evacuate at the source.

Also consider adding an activated charcoal filter as a part of the existing air circulation system so when it is running, some filtration is occurring. Might help with latent fumes.

If you had issues with humidity, etc, then I'd consider the ERV. You may still need one. But just for volatiles, to start with, I'd look at carbon filtration. At least research. I do have to say for a very large volume/space it might not be feasible, so I'm just tossing out suggested ideas.

I'll be following this post though, as I'm interested in what the knowledgeable folk have to say.

Not sure how well the welding style fume exhaustion system would work in my application. Feel it would get in the way a lot of the time.

No issues with humidity building typically maintains between 30-50% year round.

As per the carbon filter I’ll have to look and see if the Bosch mini split I have has that as an option.

 

[JunkBonds]

I would simply open doors at both ends for a few minutes to evacuate the smells and call it a day. Do that twice if needed.

 

[65’Comet5.0]

Dad just finished a 6 car garage setup, living area above. Foam insulation. Full HRV system. The HRV is actually just upstairs and it's fully automatic. You set humidity control, etc.

I would not consider it a "get stuff out of the garage" system at all. The "simple" ERV systems I've had are just an "outside air" automatic valve that allowed that air into our HVAC system.

In our garage I installed an "attic fan" above the garage portion and set it to work via a switch or a thermostat. I assume the garage doors leak enough that we're able to pull in fresh air. The idea of this system was to "auto vent" the heat from cars when they get parked in the garage, so you're not heating up the living space above it. The air is exhausted out the holes in the soffit. For an application like you've got, this is probably what I'd just, just set the timer when done and walk away.

With the cfm most common erv systems flow I figure it won’t be an instant fume extraction but I would expect it to be enough that by the next morning it’s cleared out and not days later still smelling fumes from something I did.

When they foamed it they sealed the soffits so the only fresh air it gets would be from the gap around the door or when I open a door or window but I don’t leave them open for extended periods of time usually.

 

[mike93lx]

@Denwood is the first person that comes to mind on this topic

 

[dcg9381]

With the cfm most common erv systems flow I figure it won’t be an instant fume extraction but I would expect it to be enough that by the next morning it’s cleared out and not days later still smelling fumes from something I did.

I think for what you are doing you need an "exit strategy" for the fumes. Have a gable end where you could put exhaust?

When they foamed it they sealed the soffits so the only fresh air it gets would be from the gap around the door or when I open a door or window but I don’t leave them open for extended periods of time usually.

Pulling fresh air into a sealed space probably won't help a ton if there is no place for that air to go. Your contractor did foam correctly by sealing the soffit. We had to plan for "air extraction" in the garage. Garage is traditional insulated. The living area above it is sealed in foam...

 

[65’Comet5.0]

I would simply open doors at both ends for a few minutes to evacuate the smells and call it a day. Do that twice if needed.

When it’s bad in there this is what I do currently but would be nice to finish up for the day and come out to an odor free shop in the morning. All of the entries are on the same wall so can’t really get a true cross breeze through it. In hindsight I wish I’d had them put in another window or two on the far end when it was built. I could always add a storm door to have another windows worth of air flow.

 

[65’Comet5.0]

I think for what you are doing you need an "exit strategy" for the fumes. Have a gable end where you could put exhaust?


Pulling fresh air into a sealed space probably won't help a ton if there is no place for that air to go. Your contractor did foam correctly by sealing the soffit. We had to plan for "air extraction" in the garage. Garage is traditional insulated. The living area above it is sealed in foam...

That’s what originally got me looking at an evr system was to have an inlet and outlet even when doors and windows are shut and can run all week without loosing all the heat in the winter. I would be installing this as a separate dedicated system it will not tie into the heating and cooling for the building. Just two 6” vents out the back wall one for intake one for exhaust. Yes a gable vent is an option also and could be added.

 

[pcmeiners]

"As per the carbon filter I’ll have to look and see if the Bosch mini split I have has that as an option."

For a carbon filter to work for more than a couple hours it need to be very large. with a few hundred pounds of activated charcoal. Anything less is just BS by the suppliers. Basically charcoal filtering it is impractical, as the charcoal is expensive in the quantity needed, requiring replacement or rejuvenation on a periodic basis with a good bit of labor involved.

 

[Toolfool]

When I occasionally spray lacquer-based clear finishes in my shop I set up in front of my exhaust fan, open a window on the opposite side of the room. Let it vent for half an hour after spraying. Works pretty well. Mini-split recovers decently.
The exhaust fan also helps with woodshop cleanup. Start at open window end with air hose blowing all the dust toward fan.

 

[pembol]

We have an ERV in our tightly sealed house, and seems to work OK with 50 - 130CFM of flow. It keeps the CO2 below 600ppm. But I wouldn't use brake cleaner in the house and rely on the ERV to take care of it.

I would think that an ERV in a detached garage may have some effect in the situation you describe - to keep the air somewhat fresh over the course of the week when you are not using the garage, but they are definitely not going to help with acute issues. The simplest solution would be a single room ERV, like this from Panasonic, maybe even 2 of them. That would give you up to 40 - 80 CFM or about0.3 - 0.5 ACH. Changing the air 50-60 times over the course of a week may make a difference.

 

[Denwood]

A few things to consider here.

1. Garage and house systems cannot mix, so whatever you do, it needs to be garage only.

2. I would not use an ERV in a garage, particularly if VOCs are a factor. The core is vapour permeable and may also transfer volatile gasses. You want an HRV there.

3. Normally intake/exhaust are 10 ft or more apart, but in your case you may actually want them on opposite sides of the building.

4. If your goal is just keeping some volume of fresh air in play (not extraction) then an HRV running at 30 CFM, with 100 or so in boost mode would be fine. Look for units with ECM motors so you can set a low vent speed efficiently.

5. Carbon filters like the Terrabloom 8” carbon canister have 15lbs of activated carbon and will work to address VOC concerns for a year or more depending on use. You can plop one down on the floor with an 8” ECM fan connected and it will gradually clean up your VOCs. I’m using one (after a lot of testing) for an HRV system that scrubs (very effectively) wild fire smoke at 110CFM. That said, it does not address IAQ issues like CO2 (if just filtering inside air), so an HRV makes more sense here. You can thank the pot/hydroponics industry for this very cost effective solution.

6. Plan for filtration outside the unit (on both supply and return) using off the shelf 16x25x1 filters. It's easier to just fab these up, or you can headstart with grills like these to hold your filters: https://www.amazon.ca/Steel-Return-Air-Filter-Grille/dp/B0061MOLPQ?tag=atomicindus04-20

The other thing you could look at to keep things super simple is an exhaust only system using just an 8" ECM fan with a prefilter box. I really like these AC Infinty fans: https://acinfinity.com/hydroponics-...duct-fan-system-with-speed-controller-8-inch/ . You can dial these right down from the max (at zero static) of 807 CFM so it is just idling when you're away. If you look at the energy loss (heating or cooling) of running a fan like this (say 20 CFM when you're away), depending on climate, it may actually make more sense than an HRV system for a garage once you factor in the operating cost of the HRV vs energy exchange.

If you do want to go the air exchanger path, I'd take a look at the Fantech HERO 150H-EC. It's an HRV that is 81% efficient at 70 CFM, using 23 watts. You can find a database of ERV/HRV units here and sort them by efficiency:

Section III - Heat/Energy Recovery Products

Read more on our site.

www.hvi.org

What climate zone are you in?

 

[u3b3rg33k]

You have to be careful asking a unit to do this type of work as it is not explosion proof. I think you should simply vent to the outside and pay the small energy penalty. As tightly as it is built it should recover quickly.

I wouldn't be too concerned about having a unit that's "explosion proof." none of your standard exhaust fans are going to fit that bill either.

as for ERV vs HRV, I think I'd lean towards ERV, for the humidity control.

we are talking about trace levels of fumes, you're not plumbing the ERV directly as an exhaust for a parts washer. Yes, it may bleed a bit over to the intake via the membrane, but if it's on a "low and slow" setting with no one in there, it'll likely be worth it vs the unmitigated humidity gain you'll get with an HRV, especially if you're paying to run a dehumidifier (which will ALSO condense some volatiles into the condensate!). climate zone matters for this one big time.

 

[65’Comet5.0]

A few things to consider here.

1. Garage and house systems cannot mix, so whatever you do, it needs to be garage only.

2. I would not use an ERV in a garage, particularly if VOCs are a factor. The core is vapour permeable and may also transfer volatile gasses. You want an HRV there.

3. Normally intake/exhaust are 10 ft or more apart, but in your case you may actually want them on opposite sides of the building.

4. If your goal is just keeping some volume of fresh air in play (not extraction) then an HRV running at 30 CFM, with 100 or so in boost mode would be fine. Look for units with ECM motors so you can set a low vent speed efficiently.

5. Carbon filters like the Terrabloom 8” carbon canister have 15lbs of activated carbon and will work to address VOC concerns for a year or more depending on use. You can plop one down on the floor with an 8” ECM fan connected and it will gradually clean up your VOCs. I’m using one (after a lot of testing) for an HRV system that scrubs (very effectively) wild fire smoke at 110CFM. That said, it does not address IAQ issues like CO2 (if just filtering inside air), so an HRV makes more sense here. You can thank the pot/hydroponics industry for this very cost effective solution.

6. Plan for filtration outside the unit (on both supply and return) using off the shelf 16x25x1 filters. It's easier to just fab these up, or you can headstart with grills like these to hold your filters: https://www.amazon.ca/Steel-Return-Air-Filter-Grille/dp/B0061MOLPQ?tag=atomicindus04-20

The other thing you could look at to keep things super simple is an exhaust only system using just an 8" ECM fan with a prefilter box. I really like these AC Infinty fans: https://acinfinity.com/hydroponics-...duct-fan-system-with-speed-controller-8-inch/ . You can dial these right down from the max (at zero static) of 807 CFM so it is just idling when you're away. If you look at the energy loss (heating or cooling) of running a fan like this (say 20 CFM when you're away), depending on climate, it may actually make more sense than an HRV system for a garage once you factor in the operating cost of the HRV vs energy exchange.

If you do want to go the air exchanger path, I'd take a look at the Fantech HERO 150H-EC. It's an HRV that is 81% efficient at 70 CFM, using 23 watts. You can find a database of ERV/HRV units here and sort them by efficiency:

Section III - Heat/Energy Recovery Products

Read more on our site.

www.hvi.org

What climate zone are you in?

Garage is completely separate from the house.

I’m in middle TN.

So could I go with something like this for the week when the building is unused just to keep the air fresh,

https://www.supplyhouse.com/Panason...e-100-Energy-Recovery-Ventilator-Cold-Climate

With this outdoor vent for easy simple install,

https://www.supplyhouse.com/Panasonic-FV-WC04VE1-WhisperComfort-Wall-Cap

then add one of the electric fans you linked for the times when I know I’m going to be working with something that has strong odor and want to excavate it from the builder quicker or just throw a fan in one of the doors or windows etc.

It’s not a heavily used shop by any means just me messing around with a few things here and there. Maybe once every few weeks I’ll really get into something with a strong odor and even that will probably cut back as I get more done on my project car. With it heated and cooled I just don’t open the doors or windows much so it does get stale in there so that’s why I’m leaning towards the hrv/erv system cause I’d say 75% of the time it’s all I’ll need.

 

[65’Comet5.0]

I wouldn't be too concerned about having a unit that's "explosion proof." none of your standard exhaust fans are going to fit that bill either.

as for ERV vs HRV, I think I'd lean towards ERV, for the humidity control.

we are talking about trace levels of fumes, you're not plumbing the ERV directly as an exhaust for a parts washer. Yes, it may bleed a bit over to the intake via the membrane, but if it's on a "low and slow" setting with no one in there, it'll likely be worth it vs the unmitigated humidity gain you'll get with an HRV, especially if you're paying to run a dehumidifier (which will ALSO condense some volatiles into the condensate!). climate zone matters for this one big time.

I’m in middle tn so lots of humidity so that’s why I’m leaning towards erv so I can keep humidity under control right now it stays 30-50% year round in there. The building is empty probably five days a week, it’s not a high use constant odor application it’s just a I don’t want to smell what I did last week when I go in there this week to do something. Exhaust fumes I open the main door and put a big fan in front of it so that’s not really a concern for this. The garage stays 68-72 yr round via two mini split systems so I rarely open a door or window unless starting something up, carrying something in, etc so it does get stale in there over time which is where I figure an erv would be perfect for my application I just wasn’t sure how exactly to size one.

 

[Denwood]

If you are not concerned about VOC crossing the ERV core, that unit will work fine to keep air fresh. If your winter temps don't drop below -10 C (14 F) then you don't need the cold climate unit. This is the one for temperate climates: https://na.panasonic.com/us/home-an...emperate-c-limate-erv-corded-model-50-100-cfm

You can dial the EC motors back to around 30 CFM and use boost mode if you like when in there. Boost mode you can do with a simple switch or use the Panasonic control. These units require line level controls, but any light switch (or a simple crank timer) will do, connected to the boost terminals. Efficiency at 30 CFM will likely be ~84% as it's rated 80% at 53 CFM.

Filters for these units can be pricey, so I'd still look into external filtration when using in an shop.

 

[u3b3rg33k]

I’m in middle tn so lots of humidity so that’s why I’m leaning towards erv so I can keep humidity under control right now it stays 30-50% year round in there. The building is empty probably five days a week, it’s not a high use constant odor application it’s just a I don’t want to smell what I did last week when I go in there this week to do something. Exhaust fumes I open the main door and put a big fan in front of it so that’s not really a concern for this. The garage stays 68-72 yr round via two mini split systems so I rarely open a door or window unless starting something up, carrying something in, etc so it does get stale in there over time which is where I figure an erv would be perfect for my application I just wasn’t sure how exactly to size one.

I would suggest you look at the broan "AI" series self-balancing ERVs too. they're similar in price to the panasonic, but it uses sensors to set the balance vs you setting dials. I'd look at the 75% efficient (vs the 66%), I assume it's a larger core.

 

[Denwood]

You can use one of these for the boost function to provide more fresh air when you're working: https://www.amazon.ca/Honeywell-60-...Pole-41081/dp/B07VF7FT1J?tag=atomicindus04-20