Original message
| Joe Pack
 |  "When to replace a heating /cooling system?"
, posted Wed 30 Jul 19:37  
First of all, my apologies if posting on two different forums is considered bad taste here. I am not sure who reads and answers what on this forum.
We have a natural gas Armstrong furnace with a single speed blower rated at 91% efficiency combined with a Trane XE 900 heat pump rated at SEER 9. Both were installed in 1991, making them 17 years old. Neither has any known major problems, although the heat pump did require recharging about 8 years ago because of a leak in a line fitting.
The heat pump is set to provide home heating when the temperature is 40 degrees and above. The furnace takes over when the temperature falls below 40 degrees. The heat pump also provides cooling in the summer. We are located in north-central Ohio.
Our electricity cost is now 8 cents/kwh, but, based on our typical usage, will go to about 10 cents/kwh in September. I don't have the ccf price on natural gas at hand right now, but is "typical" for our part of Ohio.
Most things I read suggest that a system of this age is expensive to run compared to today's more efficient models. Our rural electric cooperative suggests that a SEER 16 heat pump unit would save 60% on cooling costs compared to a SEER 10 model and that a new heat pump would also save considerably on heating costs at 40 degrees and above (no specific heating cost savings numbers were estimated). A hvac contractor told me that even though my furnace was rated at 91% efficiency, the newer furnaces rated at 95% would actually save more than the obvious 4% because of their 2 stage design. The design supposedly saves fuel by heating more slowly, but more often, than having the full 80,000 BTU kick in at one time. (My words, not theirs, similar to saving gas going 0-60mph slowly instead of 'pedal to the metal' acceleration.) The full 80,000 BTU force kicks in only with extreme weather. The variable speed system also takes advantage of digital thermostats that may help save energy.
I can replace the SEER 9 heat pump with a SEER 15 without replacing my furnace. At least with Trane, I am told that to get the SEER 19 heat pump I would have to also replace my furnace with the complimentary 2 stage unit. Many pages I have read seem to back this up; the higher SEER ratings depend on installing a complete, paired system.
I am interested in the advice of pros. What is your opinion? Is this something I should pursue? I am not ready to run out and spend money this instant, but, with rising electricity and natural gas costs all but a certainty, I am looking down the road.
Thanks for any input.
Joe
Joe Pack
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Replies:
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| farbeondriven
| "Re(1):When to replace a heating /cooling syst" , posted Wed 30 Jul 23:51
deffintly trane 16 seer w honeywell 8000 3h 2c t-stat with optional out door sensor for fossil fuel backup.
"if i had my life to do over id be a plumber" Albert Einstein
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| Houston204
| "Re(1):When to replace a heating /cooling syst" , posted Wed 30 Jul 19:50
Trane's 16 seer with an unloader is more impressive than their 19 seer with 2 compressors. The last time I checked the 19 was only available in the near obsolete R22 refrigerant.(This may not be the case anymore)
2 compressors would seem to double the chance of compressor failure in it's later years. (though admittedly I'm no mathemetician;)
"Tip of the Day" Remember to remove power first.
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