A high efficiency furnace should draw air from the same pressure zone ! Meaning
the inlet air pipe and the exhaust air pipe should be in close proximity to one
another allowing equal pressure changes. Both pipes should always be installed
on the same side of the house as well. Whomever said you are allowed to to draw
intake air from the basement is just looking to make some easy money on nuisance
pressure sensor trips....
CAN BE does not mean SHOULD BE.
Using outside air for combustion is more efficient. You are using air
that you paid to heat and sending it up the flue. Sounds to me the
contractor for the OP is just lazy.
On Tuesday, February 17, 2015 at 10:29:50 AM UTC-5, Ed Pawlowski wrote:
The difference in heat may not be that great. One factor is where
the furnace is located, ie is it in the heated space, an unheated
basement, garage, attic, etc. Even assuming worse case, it's not
clear to me how much difference it makes. Yes heated air is used
for combustion. But the alternative, bringing in cold outside air,
just means less heat is generated in the furnace. You're getting
more heat of a furnace with 60F air going into it than with 20F air.
I know relatively new, circa 2007, expensive houses built here that
have furnaces in unfinished basements that use the basement air.
In cold climate up here every new house going up has provision for fresh
air intake. My house was built in 1994 per R2000 specs. If
it doesn't bring in fresh air, it may cause indoor CO problem.
Summer or winter, we seldom open windows.
On Wednesday, February 18, 2015 at 11:59:02 AM UTC-5, Moe DeLoughan wrote:
I guess it's possible. Can't see what the study actually consisted of
without having paid access. The question would be what kind of appliances
did these highly sealed houses have? You would think it would have a
high efficiency direct vent furnace for example. That would eliminate
the furnace as a possible force. What's left? WH? Again typical energy
efficient new house likely has a power vent WH. It would be interesting
to see the study to find out how the CO they measured originated if they
are using modern appliances. With an old furnace using a traditional
chimney, old non-power vent water heater, etc then I can see it being a
problem, but those appliances in a new house seem unlikely.
On Monday, February 16, 2015 at 11:44:06 PM UTC-5, HVAC Man wrote:
Nonsense. Many furnaces can be installed using either outside
combustion air or inside. It's permitted per the manufacturer's
installation instructions. In most cases it makes more sense to
use outside air, especially if the furnace is located in a heated
space, because if inside air is used, the makeup cold air will be
drawn in to the structure from outside through leakage.
Yep. Not only that, but some of the earlier high efficiency furnaces
didn't even have an air intake pipe. I had an Amana, probably from the
90s, that had a standard open burner arrangement just like the furnaces
from the 70s. I just drew air from the room where it was installed. The
exhaust on the Amana, was the standard PVC out the side wall of the house.
On Tuesday, February 17, 2015 at 8:30:13 AM UTC-5, Art Todesco wrote:
Not that it matters at this point, as this is a revival of an old post,
but the install manual for the furnace would have the answer as to how
it can be installed. My Rheem, it could installed either with outside
air or using air from within.
Not really, Tony. My house was built in early 1950s and not especially
tight even with my updates to windows, doors, insulation, etc. Very
small square footage so the heating and cooling costs are pretty modest,
and I never ask for especially cool or especially warm temperatures
either. A couple grand a year pays for all my heating and cooling, hot
water heating, and other gas appliance use.
I have 2050 square feet on one level with the same in the basement. Both my
furnace and water heater have an air intake from outside, but my gas bill is
about $600.00 for a year for heating, water heating and cooking in a Toronto
suburb. Don't ask about my electric bill.
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