# Thread: How many watts does my heat pump use?

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Originally Posted by capecool
14 SEER = 14,000 btu/ kwh
36,000btu = 2.57kw
One needs to use EER to determine operating kW.

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Originally Posted by Waterloo
Gary - I think you misread what he said. It was per kilowatt hour.
I misread that - my bust, thank you.

14 EER is 14,000 btu per kw-hr.

EER = system cooling btu's (at 95F outside laboratory conditions) / condenser amp draw (watts).

A 36,000 btu system (3 tons) that draws 2571 watts is 14 EER.

Take care.

3. Originally Posted by iraqveteran
example.... 10KW heater rated at 60 amps at 240 volts....

60 x 240 = 14,400 watts.

That would make it a 14.4KW strip heater.

Seen a lot of installs where the installer didn't mark which kit he installed.
Your right it should be marked, but many are not.

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Based on what i'm hearing here, It sounds like you might have 1 8kw strip, and one 5 kw strip. Just my thought when I read the post.

I seen the guy's talking about 2k ish watts for 3 tons, I know 1 watt is equal to 3.412 Btu's, so for 2k ish watts that be about 8k btu's, Not exactly sure whats meant by those 2k watts. It sounds like the heat pump is putting out more btu's than it is taking in, about 27k more btu's actually.

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Look on the outside unit data plate (I assume your unit has one) for the FLA number. FLA stands for Full Load Amperes. It is the current the unit will draw at full normal load. There will also be a LRA, or Locked Rotor Amps number. That is not the one you want.

Multiply the FLA number by 216. Unless you have some sort of weird power, the result will be pretty darn close to the actual number of watts during normal full power operation.

You will have to find out the wattage of your auxiliary heat strips yourself. Just add that number to the number obtained previously to get the total power with heat strips in operation.

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I wasn't aware of the FLA and LRA plate.

Lets say you have a 2486 watt heat pump with no electric strips. The unit uses 220 volts at 11.3 amps.

total Btus = 2486*3.412 Btu's 8482

So, is this all heat pumps put out? A "0.7" Ton heat pump for most residential units? Also, I've seen input ratings and output ratings in Btu's, The input ratings I believe if not mistaken is higher than the output.

If so, it wouldn't even be 0.7 btu's, more like 0.5. half ton, Could this be correct?

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It is a Heat PUMP, not a HEATER. A heat pump uses energy to move heat from one area to another. Typically it will move five to ten times as much heat energy as it consumes in electrical energy to power it. A heater will only produce slightly less heat energy as the amount of electrical energy it consumes. Some energy will be lost as sound or possibly even light.

8. Originally Posted by atlantis1
I wasn't aware of the FLA and LRA plate.

Lets say you have a 2486 watt heat pump with no electric strips. The unit uses 220 volts at 11.3 amps.

total Btus = 2486*3.412 Btu's 8482
A heat pump using 2.486KW at 17 outdoor temp would have a COP around 2.
So you would be getting 16,964 BTUs of heat.

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RLA is 15.1 I think this is running load amps, could be wrong but i dont think so.

Fla is 65 amps, This could be with Heat strips included, which would trip my current breaker.

LRA 4.5 amps? Not sure what that is.

It states 230 volts. its 3437 watts according to RLA 15.1

Fla, 14950 watts (65 amps), I think this means the compressor is stuck or something.

so, 11,727 Btu's (RLA) needed for input power, 0.9 Ton, so given losses id say still about 0.7 Ton on this unit of heating output power.

I didn't see where it stated how many tons, or BTU's the unit was, I found this sticker on the removable service door, on its exposed side.

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Originally Posted by beenthere
A heat pump using 2.486KW at 17 outdoor temp would have a COP around 2.
So you would be getting 16,964 BTUs of heat.

You lost me, Not sure what cop means or what formula that is. But, I'm sure the unit is not overunity, is it?

11. Coefficience Of performance.

A multiplier to determine how much heat output per watt consumed.

Your outdoor section is a 3 ton by its model number.

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Originally Posted by bobb25
The easiest and most accurate way to find out is to turn everything off except the heat pump system and check your electric meter. First with no electric backup, and then with it.
And dividing by 240 will give you your approximate amp draw.
Or leave everything on and record the draw, then don't change anything except the heat pump being on or off then subject the draw.

see
in
http://en.wikipedia.org/wiki/Electricity_meter

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Ok, I checked it again. The model number is 4430-301

FLA Fan 1.4 amps
FLA Blower 3.3 amps
FLA Compressor Not listed

RLA compressor 15.1
RLA Fan Not listed
RLA Blower, Not listed

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