I want to insulate my garage door better because cold air is coming in from the bottom and side.
However, there are a gas furnace and gas water heater in the garage that use the ambient air. So if I seal up the garage these two applicances would run out of oxygen.
Is there a way to retrofit the two appliances so they draw air from outside the garage?
Hmmm, If you don't have fresh air intake for those appliances, isn't that code violation?
"james" wrote in news:hfojuk$f4o$ snipped-for-privacy@aioe.org:
The walls and ceiling are finished with drywall I take it?
My HVAC guy put a vent near the water heater. As far as the furnace, depends on the furnace. Our local Habitat for Humanity Restore had a 90% furnace for $125 in nice condition. They use outside air and it never mixes with the inside air.
Enclose them in a concrete block cubicle with ventilation to the outside.
Some of the newer furnace do have a hook up for supply air as well as exhaust air. Have not seen that on a hw heater yet though. Just run a 4" pvc pipe from outside to the proximity of them. Put a screen on the outside.
My water heater has that. It's an A.O. Smith about three years old.
Cindy Hamilton
I believe those are called "direct vent" just to give you a keyword
nate
Here is what I thought was an interesting article on the "myth" of using outside combustion air for wood burning appliances.
While I certainly don't claim to be a "combustion scientist", it seems to me that the same principals would apply to gas appliances.
Key question: Do you really think you can seal up your garage door to the extent that it will be air tight?
No they won't. You cannot seal the garage that tightly.
Put a vent in the wall next to the appliances.
The code here is that a gas furnace in a garage must be enclosed in a "closet" type of enclosure-- presumably so that if the car leaks gasoline fumes, the furnace will not ignite them. You can get combustion air through the ceiling in the closet, since most furnaces in that type of installation are not on an outside wall. It also requires 1 square inch of opening for every 1000 btu of input. The 90+% efficiency furnaces that vent with PVC are all but non-existant here- S Tx. Larry
This part, near the end, seems suspect to me "Building scientists say that the air in a house must be exchanged at least every three hours, or one-third of an airchange per hour, to control moisture from cooking and washing and to manage odors. One third of an air change in a 1500 square foot house is 4000 cubic feet, or 66 cfm. Note that this is the absolute minimum air change for healthy living and that most houses older than 20 years have natural leakage rates far higher than this in winter. So the air consumption of a wood stove is a tiny part of a much larger exchange of air between the house and outdoors."
My house is pretty darn leaky, but i don't believe the air is changed every 3 hours. I doubt that is true even in the summer when some of the windows are open, but I really can't imagine it's true in the winter when they're not.
Thanks. I knew that three years ago, but it fell out of my brain in the meantime.
Cindy Hamilton
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