How many watts does a heat pump use?
Updated
Running watts
3,500 W
Starting watts
9,000 W
Energy per day
28.0 kWh
A heat pump typically draws about 3,500 watts while running and up to 9,000 watts for a second or two when the motor starts. At about 8 h of use a day, that is roughly 28.0 kWh per day. These are typical values from generator wattage charts: the label on your own appliance (or its EnergyGuide sticker) gives the exact figure.
What size generator do I need for a heat pump?
Plan for at least 10,800 W: 9,000 W to get through the start-up surge, plus a 20% margin so the generator never runs flat out. Of the common sizes, a 15,000 W generator is the smallest that fits.
| Generator | Can it run a heat pump? |
|---|---|
| 2,000 W | No |
| 3,500 W | No |
| 5,000 W | No |
| 7,500 W | No |
| 10,000 W | Only just (no safety margin) |
| 15,000 W | Yes |
How long will a power station run a heat pump?
Running continuously at 3,500 W, assuming 85% of the battery is usable. The station's AC output must also handle the 9,000 W start-up surge.
| Battery capacity | Runtime |
|---|---|
| 1,000 Wh | about 15 min |
| 2,000 Wh | about 29 min |
| 3,600 Wh | about 52 min |
Running more than one appliance?
Starting surges don't add up the way running watts do. Pick everything you want to power to get your real number.
Open the Generator Size Calculator for Your HomeFrequently asked questions
What size generator do I need to run a heat pump?
At least 10,800 W: 9,000 W to cover the start-up surge, plus a 20% safety margin.
Can a 2,000 watt generator run a heat pump?
No. It needs about 9,000 W for a second or two when it starts, more than 2,000 W.
Can a 3,500 watt generator run a heat pump?
No. It needs about 9,000 W for a second or two when it starts, more than 3,500 W.
How long will a 1,000 Wh power station run a heat pump?
About 15 min, assuming 85% usable capacity, as long as the station's AC output is rated for 9,000 W of surge.
Never run a generator indoors or in a garage: see the CPSC safety guide.