# Thread: How many btu's will a heat pump put out without back-up?

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## How many btu's will a heat pump put out without back-up?

Is there a formula to determine the amount of btu's a heat pump puts out at at a given outdoor temperature providing air flo charge etc is correct?
I have a Rheem unit model # RHSL-HM2417JA Air handler and RPNE-024JAZ 13 SEER condenser. I am wondering how much heat the heat pump will put out at 11º without the electric back-up.
Thanks

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COPh = COPc + 1

3. Get the model number of the indoor coil and look up the match in the AHRI database. The "low" heating BTU's that's listed is for 17F. The "high" heating is for 47F. Use those 2 numbers to plot a curve for outdoor temp vs. BTU's to determine the BTU's at 11F... it will give you a descent number.

Otherwise, if you can get ahold of a data sheet for you heat pump, it should have heating performance data for you match-up at different outside temperatures. I plotted the data for my Trane XL16i and it's fairly linear in both stages.

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Originally Posted by rbeck
Is there a formula to determine the amount of btu's a heat pump puts out at at a given outdoor temperature providing air flo charge etc is correct?
I have a Rheem unit model # RHSL-HM2417JA Air handler and RPNE-024JAZ 13 SEER condenser. I am wondering how much heat the heat pump will put out at 11º without the electric back-up.
Thanks
Here's some comparative data for a 2-ton Goodman heat pump that's 14 SEER and 9 HSPF:

Outdoor--------Temp after indoor coil------BTU's per hr
air temp--------(based on 70F return)

25F----------------88.9-------------------17,300
20F----------------87.4-------------------15,900
17F----------------86.4-------------------15,100
15F----------------85.8-------------------14,500
10F----------------84.2-------------------13,000

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Originally Posted by rbeck
Is there a formula to determine the amount of btu's a heat pump puts out at at a given outdoor temperature providing air flo charge etc is correct?
There's no simple formula. If you want the data for a specific heat pump, you'll need to get the performance charts from the manufacturer.

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