Furnace Replacement Advice

[CGB]

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!)

Thanks.

Chet

[DK]

1. Get 3 estimaes.
2. Go 90% minimum.

Find another repairman. I doubt the heat exhcanger crack blew out the pilot. Light it and eyeball it yourself to verify this.

[jimmyDahGeek]

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.

Good Luck,

[Steve Barker LT]

Can't put a 90%'r in the attic.

[Todd H.]

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.

Best Regards,

-- Todd H.

[Speedy Jim]

Units listed for Horizontal installation?

Why not? Curious minds would like to know. Jim

[Steve Barker LT]

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.

[Gary KW4Z]

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.

[HeyBub]

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.

[Speedy Jim]

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. Jim

[Stormin Mormon]

I can't remember if I've ever installed a 90 percenter horizontal in an attic. But it should be possible. The combustion air and venting could be trouble. And it would need a condensate drain.

[trader4]

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.

[BillGill]

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.

Bill Gill

[CGB]

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.

Thanks.

Chet

[Todd H.]

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.

-- Todd H.