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  1. #14
    Join Date
    Jul 2007
    Location
    Northeast Ohio
    Posts
    17
    Maybe they put in an A/C and wired it as a heat pump. This would bring on the A/C when they want heat. Then they turn it up to 78, and the electric heat stages come on, and they finally get heat. It would use a ton of electricity since the A/C would be cooling while the resistance heat is heating. Leaving it set at a certian temp would cause the A/C unit to never turn off, with the resistance heat cycling at a temp lower than the thermostat setting.

  2. #15
    Join Date
    Dec 2007
    Location
    Southern, CA
    Posts
    520
    If a strip heat with A/C was installed I would think the bill would jump, as all the ones I've seen pull 20 amps at 208/ 230, per strip. A retirement place I did some work at had Air handlers with 3 strips in each unit. So in heat it could pull 65 amps, cooling maybe 20.

  3. #16
    Join Date
    May 2007
    Location
    Naples, Fl
    Posts
    889

    Confused

    Quote Originally Posted by 4l530 View Post
    Yeah, but disregard COP for a minute and consider this:
    Each typical resistive element draws about 20 Amps. At 230 Volts, if you have three elements, that's 13.8 kilowatts per hour.
    Now if you're using a heat pump, say it's drawing 9 Amps on the compressor and 1 amp on the ODF for a total of 10 Amps at 230 Volts. Now it's only consuming 2.3 kilowatts per hour.
    Now these are just numbers I pulled out of nowhere but that's about what you'd see. You're right, if they had electric resistance heat only, the bill shouldn't have doubled. But if they went from having a heat pump to not having a heat pump, you'd see a light bill shoot up like a rocket.
    Si, and if that 78 degree temp is anywhere near the house temp it is easy to understand the increase.

  4. #17
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Tamayra,

    When you get home check to see if the outdoor unit is running when the heat is running in your home.

    Heat Pump model would start with 25H,cooling only 24A .

  5. #18
    Join Date
    Mar 2006
    Location
    The South
    Posts
    2,195
    Tamayra

    The 24APA5 Performance model is an air conditioning condenser.

    The 25HPA5 Performance model is a heat pump condenser.

    It appears someone has made a terrible mistake.

    IMO

    see attached link

    http://www.residential.carrier.com/p...formance.shtml

  6. #19
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,346
    Tamayra,

    What was replaced with your new system? Just the outdoor unit, or both the outdoor and indoor sections? Was any ductwork replaced or altered between your old system and new?

    Also, did you ask for a heat pump when purchasing this system?

  7. #20
    Join Date
    May 2002
    Location
    Houston Texas
    Posts
    6,323
    There is a great deal of poor speculation going on. First there are very few heat pumps in Houston and the few that are around are on homes with gas heat go figure.

    Most around here that size by square foot will use 400 sq.ft. per ton not higher.

    If she had a 2.5-ton unit originally it would have had a 10 KW strip and maybe a 60 amp breaker more than likely just a 50 amp. If they then installed a 3.5-ton system it would have a 15 or 20 KW heat strip. It is very unlikely that the installing contractor would have upgraded the electrical panel to match.

    We need much more information to determine what is going on here.

    Tamayra look in my profile click on my website and call my number and I will assist you. It is likely that I know your contractor and can help you get this resolved.

  8. #21
    Join Date
    Jun 2007
    Location
    Piedmont Triad, NC
    Posts
    76
    Quote Originally Posted by dash View Post
    Tamayra,

    When you get home check to see if the outdoor unit is running when the heat is running in your home.

    Heat Pump model would start with 25H,cooling only 24A .
    I've seen it before. the supply air temp would be much lower and the electric bill would be through the roof.

    OP said "We are having to run the heat at 78 to get it warm. It is either to hot or to cold, it is never comfortable." sounds like both are on to me too.

  9. #22
    Join Date
    May 2006
    Location
    east central indiana
    Posts
    1,117
    Originally posted by classical
    There is a great deal of poor speculation going on.
    Lol, ain't that the truth. Sorry about that, chief.
    This space for rent.

  10. #23
    Join Date
    Jun 2007
    Location
    Piedmont Triad, NC
    Posts
    76
    [quote=classical;1776674] Most around here that size by square foot will use 400 sq.ft. per ton not higher.
    quote]

    400 sq. ft. per ton?????????????????????

    I've never heard that before. That would be a 4 ton unit for a 1600 sq. ft. house. Seems grossly oversized to me. I live in a 2500 sq. ft. house and I have a 3.5 ton unit.

    But then again I don't live in Houston.

  11. #24
    Join Date
    May 2002
    Location
    Houston Texas
    Posts
    6,323
    [QUOTE=wrench tech;1776704]
    Quote Originally Posted by classical View Post
    Most around here that size by square foot will use 400 sq.ft. per ton not higher.
    quote]

    400 sq. ft. per ton?????????????????????

    I've never heard that before. That would be a 4 ton unit for a 1600 sq. ft. house. Seems grossly oversized to me. I live in a 2500 sq. ft. house and I have a 3.5 ton unit.
    Yep 400 sq.ft. per ton is the norm here, some older homes actually need 1-ton per 300 sq.ft. some newer homes require around 1100 sq.ft. per ton.

    One of the main reasons that the tonnage was determined to be in that range was in the early days they were so poorly installed that that is what it took. RNC homes are still installed very poorly here in fact to a great extent even worse in the 70's. If you determine the actual functioning capacity of a system it is generally only producing about 60% to 70% of rated capacity. In the early 70's the ductwork was snap lock and had low static. The return was grossly inadequate and coupled with poor insulation in the attic and walls, over sizing was very common just to meet the needs of the house with an underperforming system.

    As flex duct became more prevalent supply side static increased further reducing system capacity and this problem still exist except with load calculations being required on RNC the system are now effectively undersized.

  12. #25
    Join Date
    Jun 2007
    Location
    Piedmont Triad, NC
    Posts
    76
    300 sq. ft. per ton? Don't that beat all! I remember helping size and area in Myrtle Beach, SC. It was under a motel built on pilings. They wanted air conditioning there so we provided it for a Veterinarian Conference. It was basicly outside with curtains. We sized it 300 Sq. ft. per ton.

  13. #26
    Join Date
    May 2002
    Location
    Houston Texas
    Posts
    6,323
    Outside with curtains would be a fair discription of some of the older homes around here. Homes built in the 20's thru 50's with no insulation in the walls original wood frame windows leak like sieve. A 900 sq.ft. bungalow needs a 3-ton best installed with a variable speed motor or more likely a 2-ton coil for humidity control.

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