Garage Exhaust Fan Recommendations

[QuaiDorkay]

I've started finishing off my detached 2 car garage (100yr old carriage house about 40m2 with attick) and have an attic fan but now that I want a TV and lounge set up I'm concerned it won't remove enough smoke fast enough for two or three smokers.   Would adding a large bathroom fan be sufficient or are there recommendations for a better setup for 2 or three smokers?  Cost not too much of a concern. Couldn't find a good thread but may have missed one.  

[Mattygukas]

Not sure but I would think a kitchen exhaust fan with an outside hood would work. Like the idea, my garage is a smoke lounge


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[AlohaStyle]

@KK33 installed a fan last year and it looked pretty good...  what say you Doug?

[Fuzz]

I'd figure out how big the room is, then match it with the appropriate size fan.

((Width x Length x Height) / 60) x 8 = fan size in cfm

((10' x 10' x 10') / 60) x 8 = 133.33 cfm

[Fuzz]

Now that I think about it, you may want to change out the air more often than 8 times an hour, as there will be up to 3 smokers. Also think about the vent placement for fresh air.

[earthson]

I would peruse your local hardware store for an attic/"whole-house" fan.  Had one in an old house I rented and it did wonders for clearing out smoke.  After a night of dominos, it was perfect the next morning.

[LGC]

Do your calculations, don't just guess

The more air exchanges per hour, the better

A large exhaust fan means nothing if you don't have matching inlets in terms of volumetric flow

Plan to condition air in the winter and summer. It's better to condition the inlet air, rather than use radiant heaters, etc

It's better to over size your inlet and install a damper for fine tuning

Baffles and remote installation will cut down on the noise

[scap99]

Put your fresh air intake low.

Capture the smoke from above.

 

If you can place your exhaust vent(s) close to where the majority of the smoking occurs, it will certainly help.

 

Assuming your garage is along the lines of 20'*20'*10', you have 4000 cubic feet of volume.

Divide that volume by the number of minutes to fully exchange the air. I picked 5, as it will allow 12 changes per hour.

Using my example you will need 800 cfm of exhaust.

 

This can be 4 bath fans at 200 cfm, or a single inline exhaust fan with several exhaust grilles above the areas where you expect to smoke.

 

At 800 cfm, you don't really need to worry about sound unless you go cheap or undersize your ductwork.

 

[QuaiDorkay]

4 hours ago, scap99 said:

"a single inline exhaust fan with several exhaust grilles above the areas where you expect to smoke."

Fantastic, will do the calculations (800cfm is spot on) but single inline with several ceiling grills and a low fresh air intake seems ideal for me.  Maybe a timer to leave it running for a few when I leave and a volume control could put this to bed.  Thanks again for all the great ideas.   Love the members here. 

[scap99]

2 minutes ago, QuaiDorkay said:

Fantastic, will do the calculations (800cfm is spot on) but single inline with several ceiling grills and a low fresh air intake seems ideal for me.  Maybe a timer to leave it running for a few when I leave and a volume control could put this to bed.  Thanks again for all the great ideas.   Love the members here. 

For inline fans, look at the offerings from Fantech and Reversomatic.

Fantech FKD 10

Reversomatic RI 900

 

Should be able to find both online for a reasonable cost.

 

 

 

 

 

[foursite12]

I remember a few posts--perhaps on another subforum--that covered this topic thoroughly, including considerations regarding potential impacts to/from HVAC systems, and carbon monoxide risks if there is a heat source or gas appliance in the space or connected via common ductwork or other passageways. Since this is a detached space, pulling all the heat out of your house through shared ducting is not likely an issue for you but that new, clean air --8 to 12 exchanges an hour--has to come from somewhere and it will likely be cold air that needs to be heated in the winter.  I think there are heat exchangers that can be helpful, but my point is that there is more to consider here (to me at least) than I would have originally thought. 

[chriswalker]

I don't post a lot on this site but... something you could consider as well is called a HRV. It's full name is a heat recovery ventilator. Although I just use an intake fan and an exhaust fan in my smoking-room if I had the money I would buy a HRV. What it does is recovers the heat from the exhausted air and applies it to the intake air inside the unit. Goodluck with your build

[chriswalker]

Having thought about this a little more...you may not live in an area where it is cold in the winter. So this unit may not be the most efficient way to get an adequate  air change without losing heat from the space. Here in canada I install many of these units because of their effeciency during the winter months. Still a slick unit because intake and exhaust work off the same fan...again goodluck

[QuaiDorkay]

I'm in Virginia with several months of cold so this option is interesting.  I was installing baseboard heaters for cold and a window unit for hot weather although I only get 3 months of each.  I see that you take a serious cfm hit with the HRV as most units are at about 200cfm and I am looking for 600-800?

[stogieluver]

My man cave is 10 x 10 x 8.  I have a Broan 140cfm ultra quiet bathroom exhaust fan in the ceiling right above my smoking area.  Can hardly hear it running.  Does a great job getting rid of the smoke.

[scap99]

1 minute ago, stogieluver said:

My man cave is 10 x 10 x 8.  I have a Broan 140cfm ultra quiet bathroom exhaust fan in the ceiling right above my smoking area.  Can hardly hear it running.  Does a great job getting rid of the smoke.

Heck yeah, one air change every 6 minutes is awesome.

Their ultra quiet stuff is spooky quiet.

 

[Fuzz]

10 minutes ago, stogieluver said:

My man cave is 10 x 10 x 8.  I have a Broan 140cfm ultra quiet bathroom exhaust fan in the ceiling right above my smoking area.  Can hardly hear it running.  Does a great job getting rid of the smoke.

 

6 minutes ago, scap99 said:

Heck yeah, one air change every 6 minutes is awesome.

Their ultra quiet stuff is spooky quiet.

 

Actually, that would be an air change every 11 minutes.

[scap99]

16 minutes ago, Fuzz said:

 

Actually, that would be an air change every 11 minutes.

800 cubic feet divided by 140 cubic feet per minute is 5.71 minutes.

 

You're calculating air changes per hour.

[QuaiDorkay]

I'm at 3,200 cubic feet so want 600cfm or more.  Installing it in attic should take care of noise.  How would you set up the low fresh air intake?  I have 2 windows and a door but want a more permanent setup but also don't want unwanted guests. 

[scap99]

2 minutes ago, QuaiDorkay said:

I'm at 3,200 cubic feet so want 600cfm or more.  Installing it in attic should take care of noise.  How would you set up the low fresh air intake?  I have 2 windows and a door but want a more permanent setup but also don't want unwanted guests. 

A wall louver with an insect screen.

Or something like this.

http://m.homedepot.com/p/Master-Flow-12-in-x-12-in-Plastic-Wall-Louver-Vent-in-White-SL12x12/100026834

[Fuzz]

46 minutes ago, scap99 said:

800 cubic feet divided by 140 cubic feet per minute is 5.71 minutes.

 

You're calculating air changes per hour.

I stand corrected, sir.

[QuaiDorkay]

17 minutes ago, scap99 said:

A wall louver with an insect screen.

Or something like this.

http://m.homedepot.com/p/Master-Flow-12-in-x-12-in-Plastic-Wall-Louver-Vent-in-White-SL12x12/100026834

Thanks!  Fantastic.  

[chriswalker]

If you are thinking of using the louvre that scap99 suggested for fresh air and position it low...one thing you might consider before cutting holes is...when we were taught about "natural ventilation systems" in trade school years ago is specified to place the intake low on the "windward" side of a building and the exhuast high on the "leeward" side of the building...so if you do have prevailing wind direction across your property this could help...I know scap99 had mentioned the low and high part but not windward/leeward...a natural ventilation system uses no fans...

Edited September 15, 2016 by chriswalker
Typo

[QuaiDorkay]

And considering the fact I am punching a whole through red cedar siding cut by hand over 100 years ago I don't want to cut twice so thanks, very helpful.   Can't say will be done tomorrow but when it is will post pics.  

[garbandz]

consider a timer on the fan so you can leave it on for a few minutes after you leave,so you can save time when it's time to go....