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  1. #1

    Carrier Furnace and A/C for Suburban Detroit

    My current furnace and A/C are over 20 years old and getting very noisy, so I suspect that they are about due for replacement. I've never been very happy with my current furnace and A/C with their single stage blower - temperature varies a lot and distant rooms are always cold in winter and hot in summer. With rising energy costs I'm getting nailed for $400-500 per month for gas in the coldest winter months, so I figure that a new high efficiency furnace will pay off fairly quickly. However, I'm less certain about whether to get a heat pump or a conventional A/C, as we spend much of the summer at our vacation cottage and leave the A/C at home set at 80 degrees while we're away. Our summer electric bills run about $150-200 per month. Our house is a 1 1/2 story contemporary design with 3200 square feet of floor area.

    A local Carrier dealer has recommended an Infinity ICS 58MVC120-1-20 (120,000 BTU) furnace and either an Infinity 16 25ANA660 A0003 heat pump or an Infinity 17 24ANA760 A003 air conditioner. The premium for the heat pump over the A/C is $1700. His calculations indicate that either option should pay off in 6-7 years vs. my current system, but he recommends the heat pump because of higher expected increases in fossil fuel prices.

    I have several concerns that I hope this talented group can help me to resolve:
    - Is an air heat pump really practical for southeast Michigan? Are the energy savings vs. a conventional A/C significant? Will it deliver the same heating comfort as a furnace?
    - As it runs basically all year, will a heat pump fail more quickly than an A/C which only runs in the summertime?
    - Do I need a top of the line Infinity ICS furnace paired with a heat pump or would a lesser model do the job? I like the blower speed and burner flexibility of the ICS, but it will (hopefully) not be providing much of my heat in spring and fall, so maybe it's overkill...
    - Initial cost is less of a factor than the operating cost, ultimate comfort level, and reliability of the system, but I don't want to buy a gold-plated system that is beyond my needs.

    Any thoughts or suggestions would be very welcome.

    Regards, Jim

  2. #2
    Join Date
    Jan 2009
    Location
    Keokuk, IA
    Posts
    5,520
    The heat pump will give you a few extra stages of heating on more mild days and if you're concerned about gas prices over the long term, it reduces you dependence on gas. With a 95% furnace, your economic balance point (point where heat pump is cheaper to operate) will probably be around 35-40F. You'll probably only use it about 50% of the time at most, so the payback could be closer to 10 years... unless gas prices go up dramatically. You might even consider oversizing hte heat pump slightly to get a little more capacity out of it in case gas prices increase in the future.

  3. #3
    Join Date
    Feb 2007
    Location
    Great Lakes Region
    Posts
    575
    I would not even consider a heat pump in your area. 1 the avg. winter temps would make it very impractical. 2 For the same reason there are probably few techs in your area qualified and experienced enough to provide proper service to a heat pump.

  4. #4
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,635
    Temperature imbalances have everything to do with the ducts and the building shell. New equipment by itself will do little to remedy that. The ducts probably need to be made larger to distant rooms. That will help a lot and may even mostly solve the problem. On the flip side, distant rooms also tend to be outside/corner rooms. Depending on the home’s construction, they sometimes lose or gain heat much more quickly than the core of the home – leaving them uncomfortable even with improved ducts.

    Be very weary about energy savings projections. They need to use real numbers – meaning they need to look at your specific usage and crunch the numbers. Glibly punching in 60% efficiency for the old furnace, as some contractors are wont to do, will give a false projection. A lot of furnaces a lot older than yours do much better than that.

  5. #5
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,089
    Unless money is no object, I can't see a 2 stage outdoor unit being an economical wise investment in your area. A 90+ furnace certainly. 2 stage and 3 stage units do not save any more gas, that's for comfort. The variable speed blowers in the high end furnaces will save on the electric bill, help overcome lousy ductwork and can be used for more summer humidity control.

    If I were in your area, and I'm not that far from it, I'd go a nice 90+ furnace, 2 stage variable speed or Rheem's Mod and a 13/14 SEER heat pump. You spend enough time in the 30s-50s that I see it as a good payback.

    Where in the metro? We have some members up that way. Western burbs you might be lucky enough to get the services of one crazy Lennox dealer we all know and love!

  6. #6
    Join Date
    Jan 2009
    Location
    bucks county, pa
    Posts
    88
    Quote Originally Posted by BaldLoonie View Post
    Unless money is no object, I can't see a 2 stage outdoor unit being an economical wise investment in your area. A 90+ furnace certainly. 2 stage and 3 stage units do not save any more gas, that's for comfort. The variable speed blowers in the high end furnaces will save on the electric bill, help overcome lousy ductwork and can be used for more summer humidity control.

    If I were in your area, and I'm not that far from it, I'd go a nice 90+ furnace, 2 stage variable speed or Rheem's Mod and a 13/14 SEER heat pump. You spend enough time in the 30s-50s that I see it as a good payback.

    Where in the metro? We have some members up that way. Western burbs you might be lucky enough to get the services of one crazy Lennox dealer we all know and love!
    Ditto..............

  7. #7
    Quote Originally Posted by BaldLoonie View Post
    (snip)
    Where in the metro? We have some members up that way. Western burbs you might be lucky enough to get the services of one crazy Lennox dealer we all know and love!
    I'm in Birmingham. Any recommendations for good dealers in my area would be much appreciated!

    Regards, Jim

  8. #8
    Join Date
    May 2000
    Location
    Indianapolis, IN, USA
    Posts
    34,089
    My cousin's "wife" lives in Birmingham, nice area. Let's see if any of our members come along and offer their services.

  9. #9
    Join Date
    Dec 2003
    Location
    south NJ shore area
    Posts
    360
    If you have it to spend do the Carier and write it off on next years taxes. as home energy star high efficiancy rebates unless your state does not have tax credit you can still get a natural gas rebate and a/c rebate he!! THROW IN A ON DEMAN HOT WATER HEATER while yoou are at it. there are rebates there too .In Nj we get kick back 4 all the tax credits we sell to h.o.
    GOOD WORK IS NOT CHEAP! AND CHEAP WORK IS NOT GOOD!

    IF YOU THINK A GOOD HVAC COMPANY IS EXPENSIVE. THEN YOU SHOULD TRY A BAD ONE.

  10. #10
    Join Date
    Jun 2004
    Location
    Howell, Michigan
    Posts
    16,176
    Birmingham is a bit of a drive for me. While it would make a good install, servicing it would be a stretch of a drive when it's super busy or the roads are bad..............

    Can anyone say "Coolwhip"? It's his backyard!

  11. #11
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Are they sure you need five tons?

    How was the cooling with your old system on a hot day?Did it run at lot?What indoor cooling temp.do you want?

  12. #12
    Join Date
    Mar 2004
    Location
    SE Michigan
    Posts
    17,912
    I don't recommend a heat pump here, stick with a 2 stage 90 and go with a DC drive for better air quality and more even temperatures in the home.

    You can PM me if you like....I grew up in Birmingham.
    " Kill a Commie for Mommy! "

    - Colonel David Hackworth (1930-2005), Korean War Vet

  13. #13
    Quote Originally Posted by dash View Post
    Are they sure you need five tons?

    How was the cooling with your old system on a hot day?Did it run at lot?What indoor cooling temp.do you want?
    First of all, I posted wrong info about my current system - sorry! Here's what I actually have now:
    - Furnace is a Luxaire #PCCU-LD20N-160A - a 160K BTU/H unit, not 120K.
    - A/C is a Lennox C16-51-1FF coil - 51K BTU/H or about 4 tons capacity.

    To answer your questions, the cooling of my current system (when new) seemed to be adequate for hot days but in recent years we have had more +90* days then I remember having back in the 80s. My current system seems to run almost constantly in really hot weather, with a daytime thermostat setting of 76*. My biggest complaint is with the air handling of the system - it just doesn't get enough cold air to the most distant rooms, and I have to leave the single-speed fan running all night to keep the bedrooms from getting really stuffy at a nighttime thermostat setting of 72* (the thermostat is in the downstairs dining room).

    The salesman did not discuss various heating and cooling capacity options with me and I was not as well-informed as I am now after reading up on the subject - a big thanks to you guys in this forum. I certainly need to ask him some additional questions, including basis he is using to determine my capacity requirements, the adequacy of my ductwork, and the possibility of adding some simple zoning to get more cold air upstairs.

    The bottom line is that I really don't know what I need, and that's why I'm posting here...

    Regards, Jim

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