I have had two contractors in to price out a new high efficiency (90%)
gas furnace for my 25 year old home located in Calgary Alberta. So we
get some pretty cold days
Both have said that a new horizontal exhaust is required out the side
of the house. Both contractors will also drain condensed water from
the furnace to a floor drain inside my basement.
One didn't recommend the high efficiency furnace. He said that the new
exhaust will produce a sizable condensation cloud which will frost over
a window which is about 3-4 feet above the exhaust. As well he thought
condensation would freeze on my neighbors house which is about 6-8 feet
Does a high efficiency gas furnace really produce a cloud of
condensation? (It gets quite cold here, with a lot of freeze thaw
cycles over the winter)
Would the furnace exhaust come out with enough force to frost up my
neighbor's exterior wall 6 feet away?
Thanks for the input everyone. Like some have suggested that particular
contractor was pretty negative on the high efficiency furnace. Due to
my finished basement any new ducting would be a pain to install
compared to a simple mid efficiency furnace.
I did get a total or four bids. Two would only install mid efficiency.
(the laziest and least knowledgeable IMHO). The other contractor who
would install high efficiency was particularly thorough and followed up
well on my questions. And like many have suggest exhaust condensation
will likely not be an issue after asking more questions.
So a new Trane XV90 is being installed next week. Anyone know where I
can get a Trane installation manual?
I have a high efficiency Amana vented horizontally just above the sill
plate. It's 12 degree's f here in Michigan now. There is less condensation
coming out than when you start a cold car to give a comparison. i have a
bedroom window about 4 feet away that has never had condensation on it. The
bushes 1 foot away look no different than those 15 feet away. This will be
our 3rd winter on this furnace. I'm happy with it.
I have a 90%+ unit, and never saw any of this 'frost'. Now I don't
have a window over my flue either, but I do have a wall about a foot
away from the exhaust. No frost.
Might want to get that third estimate. Also, check with your
accoutant, if you don't get your high effeciancy rating, you might not
get the tax credit, and the cost of fuel over the years could have you
Just thinking out loud....
tom @ www.MedJobSite.com
The condensed water is acidic, so if nothing else drains in there and it
is cast iron or copper, could very slowly eat it up. My condinsigs at
work drain outside, and I get a huge icicle in the winter. They changes
it to drain into my slop sink and I keep a bag of marble chips under it
in the hope of neutralizing it somewhat. It does eat the rocks away...
Under no conditions let this idiot inside your house again
No, and no.
Actually the condensing furnace exhaust has less moisture in it than the
standard[remember the drain?]
I have had a high efficiency furnace for over 20 years, one of the first
ones. It exhausts out the side of my basement wall with a "tee" on the end
of the pipe to split the exhaust up and down. While there is a cloud of
condensation when it is running, it creates no problems, sometimes a small
mound of ice on the ground below. It is in a corner of an "L" and does not
cause icing on the walls around it. Check other installers, that one doesn't
want to install the high-efficiency furnace, probably because he has not
learned how to do it properly, which is bad because they have been around
for 25 years.
Certainly in Calgary... I would just point out for the lurkers that the
difference in cost between the 80 and 90+ furnaces in the less extreme parts of
the continent can make the payback a long, long time. YMMV.
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