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
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.
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.
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.
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.
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!
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....
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.
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?
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.
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.
Thanks for all of the replies - lots of good info! So it looks like I should for sure replace it - if the retrofit of the needed exhaust/supply isn't a major ordeal, I will plan to go with a 95% unit.
In regards to getting the correctly sized unit, I am wondering if you could consider the BTUs of the current (old) furnace and the way it acted in various temperature extremes, and then could gauge how much of a furnce I really need. I realize that doing a load calc get good info, but I am trying to see if more real-world / existing data would trump a hypothetical calculation.
The current furnace (1988) is 116k BTUs. I live in a 1600 ft2 tri-level house. The lower level is half finished, and half un-insulated crawl space. On the coldest winter days (-25 F), the furnace would run almost non-stop when the thermostat was set to 70.. On the other colder days, it would cycle on and off - the longest span of time that it would be off would be 15 minutes. Seemed like it would cycle on and off a lot.
Could I assume that the old furnace may have been 25% efficient? If so, could I assume that I was only getting/using 87k BTUs of the 116k BTUs, in which case, a 95k or 100k 95% furnace would be OK?
Another wrinkle in all this is that I just insulated the walls of my crawl, which I assume will lesson the need of the furnace.
In all, I am ok with getting a little bit more furnace than I need becuase we are contemplating a small addition (400 ft2) that will need to be heated.
Or, should I forget all this and do a proper load calc? :jester:
Lastly, are these install prices ($3600 for a 100k BTU 80%, $4400 for a 100k BTU 95%) out of line?
Could I assume that the old furnace may have been 25% efficient? If so, could I assume that I was only getting/using 87k BTUs of the 116k BTUs, in which case, a 95k or 100k 95% furnace would be OK?
Guessing at how efficient your current furnace is, won't give you any real world info. You would also need to clock the meter, and know the BTU content of the gas.
you would also have to have an accurate heat loss calc and know the comparable "degree days" to know the true seasonal efficiency over the heating season..ARE YOU KIDDING ME! gets a little complicated ay!
!
Don't sweat it..you will definitely save .. BIG TIME with new Hi Eff Furnace. It will put a smile on your wallet.:thumbup:
To answer your other Q's a 100 K hi eff sound s good, esp considering add on..However ...and this depends a lot on your location but, IMO, I think those prices may be about 15 -20% higher than normal so, you may be able to easily get 10% off..Again there are many details we may not be aware of and those prices might be an absolute bargain. The most important key is to have a reputable installer!
existing unit from 1988 so, figure 75% at 100K = 75,000 btuh output therefore 100 K input at 95% = 95 K output so, existing was nicely sized at 75 K output PLUS future additional 400 sq ft/25% extension BUT at higher eff build requiring only extra 15 - 20% capacity/15000btuh max So I figure 95,000 btuh output shoul do it. RIGHT? Besides that's what the estimator quoted as well.
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