Furnace Replacement bids - Installation ??

19 years ago

We currently have a 80%, 140K BTU furnace, and a 60 Gal gas hot watter tank which is connected to a 6" galvinized pipe which terminates in a masonary chimmney. I beleive the chimney has an 8" clay tile inside.

We had someone do a load J, and we only need a 135K furnace. So we have chosen to go with an 135K BTU 80% furnace.

Based upon previous posts reguarding furnace installations, I have some concerns about how these companys plan on installing the furnaces.... I thought that any draft induced furnace required a smaller vent flue, and if you had a masonary chimney you had to install a SS liner.

Anyhow, Bid #1 will be installing a 80% 135K draft induced furnace using a 3" to 6" reducer to our current massonary chimney.

Bid #2 Wants to connect the new 80% furnace to the existing masonary chimney, and install a new hot water tank with a draft inducer, and vent it out a side wall.

Bid #3 Wants to install a SS flue liner (didn't say what size) in the existing masonary chimney and connect the new 80% furnace, and reuse the existing gas hot water tank.

I don't think #1 or #2 is correct! #3 is installing a SS liner, but I question if you can connect both the furnace and existing gas hot water tank to it!

I'm going to put a list of questions together and run them by these companies again. I might even get a couple of additional bids, and see how they respond.

Thanks in advance, for any insight anyone can provide on this subject!

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Comments (6)

garyg
19 years ago
An 80% efficient gas furnace wastes 20% of the fuel gas up the flue. Gas is only going to continue to increase in price. What State do you live in?
hendricus
19 years ago
Go with #3. We had a new furnace installed one year ago and the installers were required to put in a liner by local ordinance.
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allan47
Original Author
19 years ago
Garyg,

Due to the location of the current furnace, we are unable to install a higher efficency furnace, due to the length of what the flue pipe would have to be. To do this would require relocating the furnace in the house at a considerable expense.
baldloonie
19 years ago
For using a chimney with no metal liner, the National Fuel Gas Code says: the flow area of the chimney cannot be more than 7 times the outlet of the smallest draft hood appliance. If the outlet of your water heater is 3", that's about 7 sq inches. Take that times 7 and you get 49. So the code says if the chimney is more than 49 inches (7x7 or some other dimension) then you must line it. That rule works for 80 & water heater or water heater alone.

If 1 or more sides of the chimney is exposed to outdoors below the roof line, no question LINE IT!

If an 80 alone is in a chimney, no question LINE IT!

So really, the only way you could BY CODE not line the chimney is an inside chimney with 80 & water heater if the water heater draft hood meets the "7 times" rule.

#1 could be OK if the rule is met

#2 is a nut. The 80 alone needs a liner, the power vent water heater is expensive and inefficient.

#3 is good though stainless steel unless required by local code may be an overkill. Certainly nothing wrong with it, would sure hold up better than the aluminum liners.

Here is a link that might be useful: Liner info
allan47
Original Author
19 years ago
Baldloonie,

Thanks for your response! It's getting sad when a home owner has to get this involved in something so simple as replacing a furnace.

The HW tank has a 4" flue, and the hood is 5 1/4" wide. As for the chimney, three sides of it is exposed outside for close to 20 verticle Ft. Total verticle flue height is around 28 Ft.

If having the existing HW tank vented with the furnace is a problem, we can relocate it some where else in the house.

Will talk to contractor#3 again, and look for new bids and see what their response is!
paulo1310
19 years ago
I got an estimate to replace my old inefficient and noisy furnace with a York AFFINITY 9TC20N100UP11 and some duct work for $5500.I have a 5BR split level house.I believe this is a good deal.However,to install a three zoning control system they quoted it for another $6500.Is'nt it overpriced? . Thanks