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How Many Watts Does a Heat Pump Use? Mini-Split and Central System Specs
A heat pump uses about 1,000 watts for a one-room 12,000 BTU mini-split and roughly 1,900 to 4,600 watts for a 2 to 4 ton central heat pump compressor, based on its rated amps. Mitsubishi rates its 12,000 BTU MUZ-GL12NA at 920 watts cooling and 1,100 watts heating. Backup electric heat strips are the big draw: a 10 kW kit puts out 9.6 kW at 240 volts, more than the heat pump itself.
Mini-split heat pump watts (manufacturer specs)
| Model | Mode | Capacity | Rated power | Maximum power |
|---|---|---|---|---|
| Mitsubishi MUZ-GL12NA | Cooling | 12,000 BTU/h | 920 W | 1,300 W |
| Mitsubishi MUZ-GL12NA | Heating at 47°F | 14,400 BTU/h | 1,100 W | 1,620 W |
| Mitsubishi MUZ-GL12NA | Heating at 17°F | 9,200 BTU/h | 870 W | 1,240 W |
| EG4 9K Mini-Split | Cooling / heating | 9,000 / 9,700 BTU/h | 5.97 A / 6.37 A at 115V | 1,000 W input (190 W minimum) |
| EG4 24K Hybrid Solar Mini-Split | Cooling / heating | 24,000 BTU/h | 9 to 9.5 A at 208 to 240V | About 2,280 W (9.5 A x 240V) |
Sources: Mitsubishi Electric MSZ-GL12NA / MUZ-GL12NA submittal data; EG4 product specifications. Variable-speed mini-splits run below their rated power most of the time once the room is at temperature.
Central heat pump amps and watts
Ducted systems run on 208/230V. Here is what Goodman lists for its GSZB4 heat pumps:
| Model | Size | Compressor rated load amps | Volts x amps (at 230V) | Locked rotor amps |
|---|---|---|---|---|
| Goodman GSZB402410 | 2 ton (24,000 BTU) | 8.4 A | About 1,930 VA | 41.2 A |
| Goodman GSZB403610 | 3 ton (36,000 BTU) | 16.0 A | About 3,680 VA | 91.9 A |
| Goodman GSZB404810 | 4 ton (48,000 BTU) | 19.9 A | About 4,580 VA | 110.0 A |
Source: Goodman GSZB4 spec sheet (SS-GSZB4). Rated load amps is a rating, so actual running draw is usually lower. Locked rotor amps is the current the compressor can pull for an instant at startup. The indoor air handler's blower adds more on top.
Heat strips: the hidden big load
When it is very cold, or in emergency heat mode, many central heat pumps turn on electric resistance heat strips in the air handler:
| Goodman heat kit | Heat output at 240V |
|---|---|
| HKTS 5 kW | 4.8 kW |
| HKTS 8 kW | 8.0 kW |
| HKTS 10 kW | 9.6 kW |
Source: Goodman AMST air handler spec sheet (SS-GAMST-R32). A heat strip draws its full rating whenever it is on, so it can use more power than the heat pump compressor.
How much electricity does a heat pump use per day?
Watts x hours / 1,000 = kWh. The Mitsubishi 12,000 BTU unit at its 1,100 W heating rating for 8 hours uses about 8.8 kWh, about $1.50 at 17 cents per kWh. In milder weather a variable-speed unit throttles down and uses less.
Can a generator run a heat pump?
A mini-split, easily. A central heat pump, yes, with a big enough generator, but leave the heat strips off: a 9.6 kW strip alone would take most of a 10,500 watt generator. For central systems, size for the compressor's startup and the air handler, plus the rest of your essentials:
- DuroMax XP13000EH: 13,000 starting / 10,500 running watts on gasoline, 120/240V, 14-50R and L14-30R outlets for a transfer switch or interlock kit. $1,299
- DuroMax XP9500iH: 9,500 starting / 7,600 running watts on gasoline, inverter power, 14-50R outlet. $1,999
Hard-wired 240V equipment must be connected through a transfer switch or interlock kit installed by a licensed electrician. See What Size Generator Do You Need to Run a House? and How Many Watts Does a Furnace Use?
Can you run a heat pump on solar?
Yes. The EG4 24K Hybrid Solar Mini-Split takes solar panels directly (150 to 380 VDC, 2,200 W rated solar input) and runs on solar, grid, or both. It heats and cools up to 1,350 sq ft. $2,299.97. For one room, the EG4 9K Mini-Split (SEER2 29.5, 115V) is $1,679.97. For more on solar and air conditioning, read How Many Solar Panels to Run an Air Conditioner?
Need help sizing? Call 1-888-855-7286. Send us the model or the amps from your heat pump's label, and we will help with a mini-split, solar, or generator setup.
Heat pump wattage FAQ
How many watts does a heat pump use? About 900 to 1,100 watts rated for a 12,000 BTU mini-split (Mitsubishi MUZ-GL12NA), and roughly 1,900 to 4,600 VA for a 2 to 4 ton central heat pump compressor, based on Goodman's rated load amps.
How many amps does a heat pump use? About 8.4, 16.0, and 19.9 rated load amps for Goodman's 2, 3, and 4 ton GSZB4 units at 208/230V. Small 115V mini-splits like the EG4 9K draw about 6 amps.
How many watts does a heat pump use in emergency heat? Add the heat strips: 4.8 kW, 8.0 kW, or 9.6 kW for Goodman's 5, 8, and 10 kW kits at 240V.
Does a heat pump use more power in cold weather? It delivers less heat as it gets colder. Mitsubishi's 12,000 BTU unit makes 14,400 BTU/h at 47°F but 9,200 BTU/h at 17°F. When the heat pump cannot keep up, central systems turn on their heat strips, which use far more power.
Can a portable generator run a heat pump? Yes, with enough capacity and a transfer switch or interlock kit for hard-wired 240V units. Leave the heat strips off while on generator power.