How Much Electricity Does a Portable AC Use? (Cost Calc)

A portable air conditioner is easy to set up and easy to forget about, which is how it ends up running eight hours a day all summer. Its cost is simple to work out once you know its wattage.

A portable air conditioner drawing 1,000 watts, running 8 hours a day, uses 8 kWh a day and 240 kWh a month: about $43 a month at 18 cents per kWh. Your unit's label or manual lists its watts; enter them below with your hours and your rate.

The formula

Cost = watts × hours ÷ 1,000 × price per kWh. At 1,000 watts, one hour uses 1 kWh, which costs 18 cents at the U.S. average rate.

If the label lists only amps, multiply by the voltage: a 120-volt unit drawing 8.5 amps uses about 1,020 watts.

Monthly cost by wattage

At 8 hours a day, 30 days a month and 18 cents per kWh:

The same 240 kWh a month costs about $30 at North Dakota's 12.36 cents per kWh and about $111 at Hawaii's 46.28, the lowest and highest state averages for January to July 2026 (EIA). Check your state in the kWh cost calculator.

Cost by BTU size

Your unit's box lists a BTU number; its wattage depends on how efficiently it turns electricity into cooling. That efficiency is the CEER (BTU of cooling per hour per watt), so watts equal the cooling capacity divided by the CEER. As an example, at a CEER of 10 an 8,000 BTU unit draws 800 watts and a 12,000 BTU unit 1,200 watts.

At that example CEER, 8 hours a day, 30 days a month and 18 cents per kWh:

The month column matches the wattage table above, because at a CEER of 10 each BTU size maps to the same watts. A 4-month summer is about 120 days, so the season column is the monthly cost times four. A higher CEER lowers every figure: a 12,000 BTU unit at CEER 12 draws 1,000 watts, not 1,200, and costs about $43 a month instead of $52.

Cost by hours a day

The same unit costs in proportion to the hours it runs. For a 1,000-watt unit at 18 cents per kWh:

Cutting runtime is the most direct lever on the bill: halving the hours halves the cost. A timer or the unit's thermostat, set to cool only when the room is in use, does most of that work.

Reading the ratings

Portable air conditioners are rated under a federal test that reports a seasonally adjusted cooling capacity (SACC) and a combined energy efficiency ratio (CEER). A higher CEER means more cooling per watt. The SACC is usually well below the BTU number printed on older boxes, because the test accounts for the heat a portable leaks back into the room.

Hose design matters too. A single-hose unit pulls room air out through its exhaust, which draws warm outside air in through gaps; a dual-hose unit avoids most of that. See single-hose vs. dual-hose portable ACs.

Why a portable costs more than a window unit or mini split

Every AC costs the same per watt; the difference is how many watts each needs to deliver the same cooling to your room. A window unit and a mini split put their hot side outdoors, so almost none of that heat comes back inside. A single-hose portable keeps its compressor in the room and exhausts room air, which pulls warm outside air back in through gaps.

The federal portable-AC test measures that infiltration penalty, and it costs a single-hose unit a meaningful share of its rated cooling. Assuming, for illustration, a 20% penalty, a single-hose portable delivers about 80% of its cooling to the room, so it has to run about 1.25 times as long (1 divided by 0.80) to remove the same heat.

To compare the three fairly, suppose each turns electricity into cooling at the same rate, 11 BTU per hour per watt, which is the ENERGY STAR EER2 floor for a split heat pump. Each delivers 12,000 BTU/h of cooling to the room, at 18 cents per kWh:

At equal efficiency the portable costs about $12 a month more for the same cooling, purely from infiltration, before counting the heat its hose and cabinet add back to the room. A mini split's inverter compressor also modulates instead of cycling fully on and off, so over a whole season it usually draws less than a single-speed window or portable unit, widening the gap further. Ratings come from different test procedures (portables and window units use CEER, mini splits SEER2 and EER2), so treat the table as an illustration of the structural difference, not a lab result.

See the EER chart for AC units for watts per ton at every efficiency rating.

Same size, different CEER

Two units of the same SACC can draw very different power. Suppose two 12,000 BTU portables, one rated at a CEER of 9 and a more efficient one at 11 (both figures used only as an example). Their watts are 12,000 ÷ 9 = 1,333 and 12,000 ÷ 11 = 1,091.

At 8 hours a day over a 4-month summer (about 960 hours) at 18 cents per kWh, the CEER-9 unit uses 1,280 kWh and costs about $230, while the CEER-11 unit uses about 1,047 kWh and costs about $189. That is roughly a $42 difference for the season from the rating alone, worth checking before you buy.

Time-of-use rates

On a time-of-use plan, running the same unit in peak hours can cost more than twice as much. With made-up rates of 40 cents peak and 15 cents off-peak, 240 kWh a month costs $96 on peak and $36 off-peak. Cooling the room before the peak window starts, then easing off, cuts the bill.

How to cut the cost

• Size it for the room, with our BTU calculator; a unit that's too small runs nonstop.
• Seal the window kit and any gaps around the exhaust hose.
• Keep the hose short and straight, and insulate it if it feels hot.
• Close the room's door and blinds, so it cools one space, not the house.

Frequently asked questions

How much does it cost to run a portable AC for 8 hours?

About $1.44 at 1,000 watts and 18 cents per kWh (8 kWh). Multiply by your own wattage and rate for your unit.

How many watts does a portable air conditioner use?

It depends on the unit; check the label or manual. The examples here use 800 to 1,400 watts.

Is a portable AC more expensive to run than a window AC?

Often, for the same cooling. Portables lose some cooling through their hose and cabinet, and single-hose models pull warm air into the room, so they tend to deliver less cooling per watt.

Does a portable AC use a lot of electricity?

It's one of the bigger loads in a home while it runs, and it often runs for hours. Running it only in the rooms and hours you need keeps the cost down.

How much does a 12,000 BTU portable AC cost to run?

At an example CEER of 10 it draws about 1,200 watts, so 8 hours a day is 9.6 kWh, about $1.73 a day and $51.84 a month at 18 cents per kWh. A unit with a higher CEER draws fewer watts and costs less for the same cooling.

How much does it cost to run a portable AC 24/7?

A 1,000-watt unit running around the clock uses 24 kWh a day, about $4.32, and roughly 720 kWh a month, about $129.60 at 18 cents per kWh. Few rooms need nonstop cooling, so a thermostat or timer that runs it only when the room is occupied cuts that sharply.

Does a portable AC raise your electric bill a lot?

The average U.S. home uses about 863 kWh a month (EIA). A 1,000-watt portable at 8 hours a day adds 240 kWh, about 28% on top of that (240 ÷ 863), so yes, it is a noticeable jump. Running it only in the room and hours you need keeps the increase down.

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