What size generator to run a heat pump?
Heat pump (2 ton) draws about 2,400W while running and surges to 7,200W on startup. Allowing 20% headroom, size for at least 8,700W of starting capacity.
The surge is the number that matters. A generator rated to 2,400W will stall the moment the motor kicks in, because for a fraction of a second it needs 7,200W. Manufacturers advertise running watts, which is why people routinely buy one size too small.
Units that cover it
- DuroMax XP11000iH
11,000W starting · 53% headroom · $1,999
Comfortable headroom without overpaying for capacity, has a CO shutoff sensor, runs on propane as well as gasoline.
Check price - DuroMax XP9500iH
9,500W starting · 32% headroom · $1,999
Comfortable headroom without overpaying for capacity, has a CO shutoff sensor, runs on propane as well as gasoline.
Check price - Pulsar PGD95BiSCO
9,500W starting · 32% headroom · $2,499
Comfortable headroom without overpaying for capacity, has a CO shutoff sensor, runs on propane as well as gasoline.
Check price
Running more than one thing
Most people are not powering one appliance. Add everything you need at once and the calculator works out the real peak — your total running load plus the single largest surge, not the sum of every surge.
Size the whole load