How much KW heat strip for new 2.5 heat pump?
Results 1 to 12 of 12
  1. #1
    Join Date
    Mar 2010
    Posts
    5

    Confused How much KW heat strip for new 2.5 heat pump?

    I am going to buy a 2.5 ton air source heat pump for my home in central Florida. The contractors I have talked to disagree on the amount of the KW for the auxiliary heat. Either 8 or 10 KW is what I am told. One said 10 is better for it would heat up faster & then you would switch sooner to the heat pump. Another said it would cost more to have 10 KW. Both are certified Trane dealers. I myself am more concerned about the cost of using the auxiliary heat & would like to minimize that.

    Help!

  2. #2
    Join Date
    Aug 2009
    Location
    Fort Lauderdale Fl
    Posts
    282
    You answered your own question then didnt you? If your primary concern is the cost of operating go with the smaller KW heater. I am a Trane dealer aswell not that that matters much. But if your only putting in 2.5 ton hp the 8kw will be plenty....... But it has been crazy cold down here lately ;-). But if it is really that big a deal for you have each contractor do the load calcs on the space why guess when it can be down easy enough

  3. #3
    Join Date
    Feb 2010
    Posts
    58
    Did your contractors perform a heatloss calc. for your home? If so, go with aux. heat strip that matches heatloss. Use outdoor thermostat to control heat strip operation.

  4. #4
    Join Date
    Mar 2006
    Location
    The South
    Posts
    2,126
    justkay

    what is your normal average winter temp? I know this winter has had lows way below the norm but Orlando area average is around 60 degrees.

    So it is doubtful you would use strip heat backup very often either as auxilliary heat, emergency, or in defrost mode. With a Trane, you will have electronic demand defrost so again, it would be rare that you would use the defrost mode. Definitely not a 10 KW. In fact I might consider going as low as a 5 KW which would yield about 17 KBTUs.

    IMO
    Good Luck!

  5. #5
    Join Date
    Mar 2010
    Posts
    5

    Confused

    I do not know if a heat/loss calc was done. A manual J was done. Is the former part of that?
    I also do not know what the average winter temp is here in C;earwater, FL. Probably close to Orlando's I would guess.
    What I want to do is minimize the use (& expense) of using the auxiliary heat strip. And the contractors I have had out seem to disagree on this as far as the impact of the size of the strip is concerned.

  6. #6
    Join Date
    Jun 2007
    Location
    The Twilight Zone
    Posts
    2,964
    Quote Originally Posted by justkay View Post
    What I want to do is minimize the use (& expense) of using the auxiliary heat strip.
    Get a thermostat w/outdoor temperature sensor that is capable of locking out the aux electric strips above a certain temp.

  7. #7
    Join Date
    Jun 2007
    Location
    The Twilight Zone
    Posts
    2,964
    Quote Originally Posted by justkay View Post
    One said 10 is better for it would heat up faster & then you would switch sooner to the heat pump.
    That statement makes no sense.

  8. #8
    Join Date
    Aug 2009
    Location
    Kansas City
    Posts
    258
    The typical 2.5 ton heat pump system in the KC area uses a 10 kw backup strip heater. Beings that our design temp is -5 TO 0 degrees outdoor temp it would be safe to say 8 kw would work fine. The 10 kw heater kit would use more amps but not run as long due to increased btu output. Comfort would be the noticeable difference. The btu loss in the house would be the same regardless of the heater kit. The run time of the equipment is shorter with the 10 kw. Also some heater kits are rated 10 kw and only supply 8 kw depending on the power supply voltage.

  9. #9
    Join Date
    Mar 2007
    Location
    South Texas
    Posts
    213
    it's going to take the same amount of energy to heat the house with 8 or 10 kw electric heat. It will heat faster with the 10kw, but the heat loss on the house will be the same regardless of the size heater. The fan would have less run time but it probally would not be noticible on you electric bill.

  10. #10
    Join Date
    Jul 2009
    Location
    Plant City, Florida
    Posts
    2,198
    Quote Originally Posted by justkay View Post
    I am going to buy a 2.5 ton air source heat pump for my home in central Florida. The contractors I have talked to disagree on the amount of the KW for the auxiliary heat. Either 8 or 10 KW is what I am told. One said 10 is better for it would heat up faster & then you would switch sooner to the heat pump. Another said it would cost more to have 10 KW. Both are certified Trane dealers. I myself am more concerned about the cost of using the auxiliary heat & would like to minimize that.

    Help!
    Will the existing circuit for your A/H be able to carry the load for a 10KW heat strip?

    If so, go with a 10KW.

    if not go with an 8KW.

    I wouldn't use a heat strip smaller than 8KW.

    not much of a difference either way, the larger one will pull more amperage but heat up the house quicker, so it will run less time, the 8kw will heat the house up slower and have to run longer, in the end you will pay the same amount for heat.

    I don't think there is any difference in price between an 8kw and a 10kw heat strip.

    In Clearwater you won't be using the strips very much unless we get real cold weather like we just had.

  11. #11
    Join Date
    Mar 2010
    Posts
    5

    Wink How much KW heat strip for the new 2.5 ton heat pump?

    Let's see if I understand this. There really isn't much difference in the cost of using an 8 or a 10 KW heat strip for the heat pump's auxiliary heat. The latter will heat up the house faster but use more amps. I currently have a split non-heat pump system with an A/C outside & a heat strip (unknown amt) inside the air handler. The heat strip uses a 60 amp breaker & the A/C uses a 50 amp breaker. Those who have given me quote do not feel my electrical panel will be a problem.

  12. #12
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,595
    There is only a 6,826 BTU difference between a 8KW and a 10 KW aux heat kit.

    Since your supposedly already going to be moving 1,000 CFM. Your moving plenty of air for a 10KW aux heat kit.

    Where you could notice a difference. Is when the heat pump goes into defrost.
    The 10KW heat kit will give you a warmer air temp from the registers.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event