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-   -   Replace my furnace now or later? 80% vs 95%? HELP (http://www.diychatroom.com/f17/replace-my-furnace-now-later-80-vs-95-help-157965/)

Mr Blotto 09-25-2012 02:52 PM

Replace my furnace now or later? 80% vs 95%? HELP
 
OK - I live in the Chicago area. I have an Bryant 100k BTU natural gas furnace that was installed in 1988. This summer i had to replace the blower motor capacitor, and yesterday I had to replace the 3-way gas switch. Since I have owned my house (5 years), the furnace has made a lound clicking sound when the furnace starts to heat up (after the call for heat but before the blow motor starts). No idea what that clicking sounds means, but I have a feeling that I am near the end of the life span for this furnace, or that numerous parts are going to start to go bad on me fast. Would you say that is a correct assumption?

I have gotten quotes for 80% and 95% replacement furnaces (100k BTU American Standard)

$3450 for the 80% installed
$4200 for the 95% installed

I have been told that after 5/13, 80% furnaced will no longer be available. I am kicking myself for not getting this last year so I could have taken advantage of the federal tax credits for 95% furnaces.

If you were in my shoes, what would YOU do?

A - keep my old furnace going
B - get a new 80% furnace while they still make them
C - get a new 95% furnace and start taking advantage of the cost savings ASAP


THANKS!

bob22 09-25-2012 03:34 PM

Whatever your avg bill for heating season has been, assume maybe a 15-20% reduction. That'll help figure out payback period of the $750 difference (and likely better comfort with a more modern model).
Your existing is nearly 25 years old and is at the point of replacement IMO especially with cost of fuel only to go up not down.

beenthere 09-25-2012 04:57 PM

Do a load calc, and find out what size furnace you really need. Your 1988 one is probably 40 to 60% over sized. A new correctly size 95% one will save you a lot of money and make you feel more comfortable in your home.

http://hvac-calc.com/

Its worth the 50 bucks.

Marty S. 09-25-2012 05:27 PM

Ditto on what the others said,get a correctly sized 95%. Don't put it off. That clicking noise could well be a large crack in the heat exchanger.

concretemasonry 09-25-2012 05:32 PM

I had a choice between installing either 80% or 90% as replacement for a old furnace that had a cracked exchanger.

I chose to go with an 80% Bryant of the right size because it was a good "fit" into the space and did not require a complicated combustion air and venting system that did not also require a lot of problems since both levels of the house were finished.

So far (after 3 years, I am satisfied and my maximum monthly heating costs (in MN) are much lower than my maximum monthly AC cooling costs.

I would expect a more complicated system such as a 90% furnace would require more expensive maintenance.

Dick

beenthere 09-25-2012 07:18 PM

Quote:

Originally Posted by concretemasonry (Post 1017265)
I had a choice between installing either 80% or 90% as replacement for a old furnace that had a cracked exchanger.

I chose to go with an 80% Bryant of the right size because it was a good "fit" into the space and did not require a complicated combustion air and venting system that did not also require a lot of problems since both levels of the house were finished.

So far (after 3 years, I am satisfied and my maximum monthly heating costs (in MN) are much lower than my maximum monthly AC cooling costs.

I would expect a more complicated system such as a 90% furnace would require more expensive maintenance.

Dick

They actually don't. Main additional thing on a 90%plus is the secondary heat exchanger. No other mechanical or electrical devices are on a 90%plus that an 80% doesn't have.

techpappy 09-25-2012 08:43 PM

IMO It is not worth replacing furnace just for the added efficiency However , when you DO have to, (which is now) then, highest efficiency is a the clear choice!

ben's plumbing 09-25-2012 08:45 PM

stay with 95%....got an email that stated after may 2013 ...no more 80% furnaces will be sold..anyone else hear this......95% will save you more anyway....

Missouri Bound 09-25-2012 08:55 PM

Quote:

Originally Posted by Mr Blotto (Post 1017167)
C - get a new 95% furnace and start taking advantage of the cost savings ASAP


THANKS!

Look at it this way...for every $100 you spend now on heating your home, $20 of that was wasted going up the chimney / flue.
A 95% will lower that to $5.
Adds up fast during Chicago winters. :yes:
That is what I would do. And you have gotten nearly twice the life expectancy of your current furnace. Time to loosen the wallet.

techpappy 09-25-2012 09:33 PM

Do furnaces only have a 15 year life expectancy now..they were always 20 -25 years not that long ago AND I have seen some furnaces (from the 50's) stll in service after 50 years of operation

So, what is current life expectancy of new 95% unit?

beenthere 09-26-2012 04:25 AM

Average around 20 years for gas furnaces.

techpappy 09-26-2012 07:37 AM

Thanks Beenthere..good to know.

Doc Holliday 09-26-2012 08:29 AM

Quote:

Originally Posted by ben's plumbing (Post 1017395)
stay with 95%....got an email that stated after may 2013 ...no more 80% furnaces will be sold..anyone else hear this......95% will save you more anyway....

80% will only become the minimum after 2014 0r 2016 for the southern region.

hvac benny 09-26-2012 09:00 AM

Quote:

Originally Posted by ben's plumbing
stay with 95%....got an email that stated after may 2013 ...no more 80% furnaces will be sold..anyone else hear this......95% will save you more anyway....

80% furnace haven't been allowed in Canada for a couple of years now for retrofit, and even longer for new construction. Its only a matter of time before the states catches up.

raylo32 09-26-2012 02:55 PM

Well, if 80% gets phased out for retrofits that could cost folks a lot of $ in older homes that are not set up for the Cat IV venting requirements. To the extra $ for the 95% equipment costs one needs to add the potentially considerable cost of installing the vent and intake lines.

I upgraded my furnace last year and there was literally one spot that met the code for the vent location without having to run new PVC or stainless pipe up and out the roof through 3 levels of finished space. Doors, windows, inside and outside corners, vent pipe slope, height above snow line, etc, etc.... whew. It can be challenging, esp in multi family buildings like condos and townhomes that were not designed with Cat IV in mind. If I had to run the pipe out the roof I would have likely just opted for an 80% replacement.


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