How Much Does It Cost to Run a Mini-Split?

At 8 hours of use and a 60 percent effective duty cycle, about 130 kWh a month, roughly $22 at the national average rate. In mild weather it can be well under that. In a heat wave or a cold snap running 24 hours, double it.

Yes, for the same cooling. A 20 SEER2 mini-split uses roughly half the electricity of a 11 CEER window unit per BTU delivered, and it is much quieter. The up-front cost is far higher, so the payback depends on how many hours a year you run it.

The mini-split, by a factor of 2 to 3 in most weather. It moves heat in from outside instead of making it, so a kWh of electricity delivers 2 to 3 kWh of heat. Below about 5 degrees F the advantage shrinks, and a space heater can match it only on the coldest nights.

For a few hours, raising the setpoint 2 or 3 degrees costs less than turning it off and letting the room drift, because the recovery at full speed is the unit's least efficient mode. For a day or more, turn it off.

About 900 W at full speed for a typical 20 SEER2 unit, and often only 200 to 400 W once the room is at temperature and the inverter compressor slows down. The start-up surge is small, around 1,200 W, because the inverter ramps the compressor up gradually.

About 16 cents an hour at full speed, since 0.9 kWh x $0.173 = $0.16. At a low steady speed of around 300 W it is about 5 cents an hour, and the 60 percent effective duty cycle used on this page averages about 9 cents.

About $2.24 a day on the page's assumptions: 0.9 kW x 24 hours x 0.6 = 12.96 kWh, and 12.96 x $0.173 is about $2.24. Over a 30 day month that is roughly 389 kWh, about $67, and less in mild weather when the compressor idles at low speed.

No, it is one of the most efficient ways to heat or cool a room. At 900 W full speed it delivers 12,000 BTU, while an 8,000 BTU window AC draws about 750 W, and in heating mode it delivers 2 to 3 units of heat per unit of electricity, compared with 1 for a space heater.

Yes, it is one of the easier cooling loads for backup power. It needs about 1,200 W at start and up to 900 W while running, so a 2,000 W generator or a power station with a 1,500 W or larger inverter can handle it, provided the output matches the unit's voltage, since many 12,000 BTU models run on 230 V. A 1 kWh battery lasts about an hour at full speed and roughly 3 hours at a 300 W low speed.

Often yes, in cold weather. Heating draw is similar to cooling, but efficiency drops as the outdoor temperature falls, and the unit spends energy on defrost cycles. At 5 degrees F a standard model may deliver only 1.5 to 2 units of heat per unit of electricity, and some switch on resistance backup heat below that.