Just learned today that my 32 year old hot air, natural gas furnace which is
in the attic and supplies heat to 4 bedrooms and 2 baths isn't working
because there are two cracks in the heat exchanger (pilot blew out because
of this, per gas man). Apparently I need a new furnace.
Gas company estimate was $3600 for a "Comfort-Aire," 80% efficient,
horizontal flow, from 75,000 to 100,000 BTU's (old one was 105,000 BTU but
gas guy said I could get by with about 80,000). This price is for the unit,
installation, permits, and 2 years free service. I don't know the length of
the guarantee but he said most of the horizontal flow units have a life span
of about 10 years. There is no duct work to be done other than what is
involved in removal old unit and attaching the new one. There is no air
conditioning involved in this.
The price sounds high to me, but we do live in Massachusetts and costs here
are egregious. I'm told that the replacement furnace is a "middle-of-the
road" furnace. He said Comfort-Aire is the same furnace sold under the
names Ruud or Rheem or Conquest.
I know nothing about furnaces. Any recommendations about this furnace,
other brands, reasonable price, etc. would be appreciated. I don't even
know any good non-gas company guys to call here. We repeatedly get burned
with high plumbing costs (e.g. $400 to remove and replace one outside faucet
for the water hose, took 15 minutes, honest!)
Of course it would depend on the climate zone. I was told by 6 out of 6
companies that bid my job, that putting a 90+%'r in an unconditioned area
can cause problems in the event of a power failure. Seems that during such
an event, the condensate drain could freeze and the condensate would then
pool in areas of the unit that it shouldn't. Then when it freezes it could
bust the heat exchanger. I hope I repeated that all properly. When below
the house, these units are not likely to be subject to freezing temperatures
even during extended periods of no power.
Just for the record, the man I ended up going with also talked me out of the
two stage furnace. He explained that it is a waste of equipment when using
a heat pump.
"Speedy Jim" < email@example.com> wrote in message
Get at least two additional estimates. I just recently had a new
furnace installed with all new duct work(hot and cold air) with
additional runs and with air. The first company wanted $12,000. I
called a local builder who has done work for me in the past and he
recommended someone. That estimate came in at $5,500. It was also a
better more efficient unit. It took 2 1/2 days but most of the time
was installing the duct work down in the crawl space. I would think
you would want a least a 90+ unit. 80,000 btu also sounds a little
small for a 4 bedroom 2 bath house. So I strongly recommend getting at
least another estimate. After all estimates s/b free and they help to
keep contractors honest.
Look for an American Standard or Trane dealer
Look for a Rheem or Ruud dealer
Look for a Bryant or Carrier dealer
Get quotes from all of em. I got several quotes on replacing my
100,000 BTU Carrier unit that was 65% efficient or so.
I paid $3824 after deciding on a Bryant (Carrier with less marketing
overhead, best I can tell) 2-stage 94% AFUE, variable speed
80,0000/52,000 unit installed by a company holding the highest Bryant
certification level in the area. The person who quoted it also took
the most time looking at duct counts and sizes, vent opening counts
and researching the existing unit's output. Their quote included the
10yr parts/labor extended warranty from Bryant, and I also went for
the Evolution Control which probably wasn't necessary, but given that
the quote was also $1000 less than the Carrier dealer's quote on the
same system, what the heck. Being able to get humidification while
the heat off is sorta a plus, but you can save some $ skipping the
Evolution thermostat and reusing the t-stat you already have.
In your area, I think going with a higher efficiency unit than 80% is
going to pay off, unless you're planning to move very soon and are
strapped for cash. I'm in Chicago, and I've already seen marked
benefits in my gas bill this winter vs last in comparable degree day
months. The 2-stage gas valve is pretty slick as on moderately cold
days, the unit gets by on the lower fire burner alone, and you don't
get hit with short cycles of big blasts of heat from a single stage
furnace. Also, teh variable speed motor does definitely contribute to
better comfort throughout the home as it continuously runs on a lower
speed to distribute air throughout the house so your far end rooms
don't end up so much colder than more central rooms. And you don't
have the noise and electricity cost associated with running a one
speed blower full tilt 24/7 to get a similar effect.
Time will tell if the more complex variable speed motor will prove to
be a maintenance/reliability worry. Some folks make a big deal about
that, but with a 10 year parts/labor warranty, I won't be worrying
about it for quite a long time.
It might make the house a little more comfortable, but my bet is that
running the blower more to move air around is costing you quite a bit
of money. The blower energy used is just one component. The other
is that you are now moving room temp air through duct work, where in
most cases, it's going to move through cold areas, ie basement or attic
and lose heat there that it would not lose if the blower did not have
it circulating. None of these is perfectly insulated and most also
have some actually air leakage as well.
It is true that many brands are actually manufactured by other name brand
companies and in the case of Comfort-Aire I don't know and Bryant is
another. I do know that Rheem is a company with a solid reputation but you
are also going to find that other good companies charge for their
advertising in the price of the unit (Lennox, Carrier, Trane, etc). Like
the other post said, you can go 80% but I would recommend 90% and make sure
that the ducts are well sealed and taped so you don't go losing much. Grab
several quotes, as instructed, and you might possibly also ask if they would
allow you to purchase your own unit and get a price for their installation
only. Verify that they are knowledgeable though in installation of the
brand you choose.
On 12/26/06 3:17 PM, in article
I don't understand how a cracked heat exchanger causes the pilot to go out.
Cracks, per se, are no big deal to most people since the only thing they
prevent is Carbon Monoxide from the combustion process from reaching you.
Get a CO detector and/or a canary and you'll probably be okay.
The forced air blower can create a very hefty
breeze blowing *out* of the heat exchanger.
Depending on the unit's design and the location
of the crack, that breeze can easily be directed
toward the pilot and blow it out. Or, it might
be aimed at a burner and cause flame lift-off.
On the other side of the coin, air flow around
the surfaces can create low pressure areas which
can potentially suck combustion products back
*into* the heat exchanger.
No situations are alike and one has to allow for
almost any possible hazard.
I don't recommend particular brands, but I have a gripe
with my York 93% furnace. The fan is too loud. I
finally turned the speed down and got it a little bit
better, but it is still quite loud.
So be sure and check on how loud it will be.
Definitely appreciate all your answers. It's nice to have some help.
I'm now waiting for the 3rd of 4 estimates. General consensus now is no
high efficiency because it is in the attic. It only heats the upstairs
(furnace in basement does the downstairs) and we really don't run it very
much because the kids are gone and only one bedroom is in use. We rely on
the electric blanket. So, extra problems of a high efficiency unit will
make me opt against that.
If I learn anything exciting, I'll report back.
Seems like a very reasonable tack. If it's a 2nd furnace handling
upstairs only and in the attic, yeah, 80% is the way to go. The
lower level furnace does most of the heavy lifting anyway.
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