On Feb 3, 9:21*am, MNRebecca wrote:
Thanks for all the feedback, everybody. *I'll look it over thoroughly.

MNRebecca wrote:
*If I disconnect the pipe from
the furnace and let it draw air from the room instead (which I'm told,
by the repair guy, is harmless),
(Doug Miller) wrote:
He's right. It's less energy-efficient, because cold air is drawn into the
house to make up for it, but it won't harm anything (other than your bank
balance).

I'm a little confused by this. *The intake pipe draws cold air from
outside. *The air in the room is far warmer. *Where/how is cold air
being drawn into the house to make up for the fact that I disconnected
the intake pipe and made the furnace use room air instead?

Doug's answer to this question was good, but I think he fell into the
trap of knowing too much about the issue and giving not enough
information.

Your furnace blows exhaust (air) out the "chimney" (a PVC pipe in your
case)
when it runs. This tends to decrease the air pressure inside your
house, since
there's less air inside.

Normally, your furnace pulls air in through the intake pipe and this
balances the
pressure, but when you disconnect it and use "inside air", air from
outside moves
toward the area of lower pressure (inside your house), through
whatever gaps it
can find (around windows, doors, etc.) This air is colder than the
air
inside your house, which will make your furnace run more to keep the
air in your
house at the temperature set by your thermostat.

Cindy Hamilton