Comments on: Want Bad Air? Put a Heating & Cooling System in Your Attached Garage

By: Dana Hansen

Dana Hansen — Wed, 28 Nov 2012 02:44:00 +0000

I was wondering why you were
I was wondering why you were taking pictures of my garage??

By: Bob

Bob — Tue, 27 Nov 2012 07:09:29 +0000

Furnaces in closets attached
Furnaces in closets attached to the garage is the rule in our area. Typically the water heater is located in the closet also. This is how my own home is set up. Ductwork goes through open ceiling into the attic, then into the house.

I didn't build the house, but if it was up to me the furnace would go inside along with most if not all of the ductwork.

By: David Butler

David Butler — Tue, 27 Nov 2012 00:59:07 +0000

Garage furnaces are very
Garage furnaces are very common where I live. Gas water heaters typically sit next to the furnace, which only adds to the risk.

I heard a story that the local utility killed the local Environments for Living program some years ago when the rater refused to pass homes with garage furnaces. For the most part, builders weren't cooperative. Those that complied moved furnace to the attic. Sigh.

By: Thomas Billups

Thomas Billups — Tue, 27 Nov 2012 00:40:11 +0000

Sadly I see this all the time
Sadly I see this all the time.
Yet another advantage of electric cars - no CO emissions (from the vehicle) ...Be great when EVs w/ solar charging becomes reasonably accessible.

By: Allison Bailes

Allison Bailes — Mon, 26 Nov 2012 22:09:32 +0000

M. Johnson
M. Johnson: You've hit the two main ways to do that - positive pressure ventilation system and exhaust fans in garage. As you point out, the former is mainly for use in warmer climates. Some green building programs, like LEED for Homes and EarthCraft House, give points for garage exhaust fans. They require that no HVAC systems be installed in garages but give points for installing exhaust fans in the garage. If you're installing a fan, they require it to run continuously or be on a timer or motion sensor. I don't know how many builders do that, but I imagine it's a small number.

There's another way to avoid negative pressure in the home, too, and it's one you've mentioned in comments in other articles here. Unbalanced duct leakage with more supply leakage outside than return leakage creates negative pressure in the house.

By: M. Johnson

M. Johnson — Mon, 26 Nov 2012 20:14:50 +0000

Allison, you speak of ".
Allison, you speak of "...Keep the air pressure in the garage lower than the air pressure in the house". What recommendations do you have for that?

In a cooling climate, one could use a fresh air (FA) intake on the return plenum, to supply additional outside air. Of course duct sealing remains important. Other things being equal, the FA will result in a small positive pressure inside the house, vs. outdoors and presumably vs. the garage. This is fine in a hot-humid climate, but many have said it inadvisable in a heating climate. What other methods could achieve the pressure differential vs. the garage?

One that comes to mind would be a dedicated exhaust fan between the garage and outdoors. With the low wattage type fans (e.g. Panasonic), one could run 24/7 without excessive costs. But does anyone actually do that?