The No. 1 expense of the air conditioner is electricity.

There are several ways to reduce how much does it cost to run an air conditioner. The two main ones are:

  1. Buying an air conditioner with a high energy efficiency rating (EER, SEER, CEER ratings are valid specifications).
  2. Reducing the number of hours per day that you use a given air conditioner.

On average, running an air conditioner costs between $0.06 and $0.88 per hour. Let’s calculate how much does air conditioning cost per month (running 8h per day):

  • Low end: $14.40/month.
  • High end: $211.20/month.

This is quite a large cost interval because air conditioners range from small 5,000 BTU portable AC units to large 50,000 BTU mini-split units.

Note: Make sure to use the air conditioner cost calculator (you’ll find it further on) to estimate your electricity bill. Here’s an example of an AC running cost calculation for 24,000 BTU AC with $0.1319 kWh price:

air conditioner electricity cost calculator example

Obviously, a 5 zone mini split air conditioner electricity expenditure per hour is several times greater than that of a single 12×12 room AC unit.

For example, if you have a 5,000 BTU AC unit, powered by 600W, the maximum cost of running such an air conditioner is $0.08 per hour.

Every air conditioner has a unique energy-efficiency profile. To best estimate how much does it cost to run your particular air conditioner on per hourly basis, we have prepared 3 sections to help you out:

  1. Table with a per hour running cost of the most common air conditioners.
  2. Calculator. You can input power (W) and electricity costs in your area, and the calculator will calculate how much that particular air conditioner costs to run per hour.
  3. Formula. The mathematical background of how to calculate the electricity costs for any air conditioner.
  4. Per week, per month, and season calculations. Examples of how much you’ll pay for electricity if you run an air conditioner for longer periods of time.

Per Hour Running Cost Of Most Common Air Conditioners

3 most common air conditioners and the most common capacities (in BTU) are:

  1. Portable air conditioners (5,000 BTU – 15,000 BTU).
  2. Window air conditioners (5,000 BTU – 20,000 BTU).
  3. Mini split air conditioners (12,000 BTU (1 ton) – 48,000 BTU (4 ton)).

If we presume that all these devices have an EER rating of 10 (estimate) and that the average cost of electricity in the US is $0.1319 per kWh, we can approximate the costs of running these 3 kinds of air conditioners:


How Much Electricity Cost A Portable AC Use? (Table 1)

Portable AC Unit (BTU) Estimated Cost Per Hour
5,000 BTU Portable Air Conditioner Costs $0.07 per hour
8,000 BTU Portable Air Conditioner Costs $0.11 per hour
12,000 BTU Portable Air Conditioner Costs $0.16 per hour
15,000 BTU Portable Air Conditioner Costs $0.20 per hour

How Much Does It Cost To Run A Window Air Conditioner? (Table 2)

Window AC Unit (BTU) Estimated Cost Per Hour
5,000 BTU Window Air Conditioner Costs $0.07 per hour
10,000 BTU Window Air Conditioner Costs $0.14 per hour
15,000 BTU Window Air Conditioner Costs $0.20 per hour
20,000 BTU Window Air Conditioner Costs $0.26 per hour

Cost Of Running Mini Split AC Unit (Table 3)

Mini Split AC Unit (BTU) Estimated Cost Per Hour
12,000 BTU (1 ton) Mini Split AC Costs $0.16 per hour
24,000 BTU (2 ton) Mini Split AC Costs $0.32 per hour
36,000 BTU (3 ton) Mini Split AC Costs $0.48 per hour
48,000 BTU (4 ton) Mini Split AC Costs $0.64 per hour

You can see that the cost of running the most common air conditioners range from $0.07 to $0.64 per hour. It’s quite interesting to see that running the smallest air conditioners will cost you less than $0.10 per hour.

Formula: How To Calculate How Much Running An Air Conditioner Per Hour Costs

In most basic terms, the formula of how much electricity expenditure we can expect from an air conditioner comes down to two things:

  1. Maximum power of the air conditioner (measured in W). We can find this in the specifications of every AC unit.
  2. Price of electricity in your area (in cost per kWh)

calculating how much is the energy cost of running the air conditioner

Kilowatt-hour is a unit for the amount of electricity. 1 kWh simple means that we can run a 1 kW (equivalent to 1000 W) electric device for 1 hour. We have to pay for that 1 kWh of electricity; the price in the US ranges from $0.095 in Louisiana to $0.3277 in Hawaii per kWh. The cost of kWh in California, for example, is about 20 cents.

Here is the formula for the per-hour cost of running an air conditioner:

CostPer Hour = PowerAir Conditioner(in W) * Electricity CostPer kWh / 1,000

A simple example would be a 10,000 BTU portable air conditioner, powered by 1000 W, in California. Here’s how you can use the formula to calculate the cost of operating the air conditioner on your own:

CostPer Hour = 1000W * $0.20 / 1,000 = $0,20 per hour

Note that this calculation is only a theoretical estimation. In practice, the air conditioner can drain less energy because it doesn’t always operate at 100%.

How Much Does AC Unit Cost Per Day, Week, Month, And Season

In the long run, it makes sense to know how much will we spend on electricity overall. Per hour calculations can help us estimate the price of electricity we spend running an air conditioner daily, weekly, and monthly. We can also assess what an overall yearly or per season bill will be for air conditioning.

The key question here is how many hours per day do you have the air conditioner turned on. During the 3-month long summer season, most households run for 8 hours per day.

Let’s again take 10,000 BTU, powered by 1,000 W, as an example. Let’s say this unit is based in California, where the price of electricity is $0.20 per kWh.

10,000 BTU AC Unit Est. Cost (Per Hour) East. Cost (Per Day) East. Cost (Per Week) Est. Cost (Per Month) East. Cost (Per Season)
$0.20 $1.60 $11.2 $48 $144

Be Aware These Are The Maximum Rates (In Practice, You Pay Less For Electricity)

With all these calculations, we have estimated that the air conditioner is running at 100% capacity. For example, 1000 W AC is always presumed to use 1000 W of energy. The bigger 5 zones mini-split system can easily draw 3000 W.

In practice, air conditioners don’t always run on 100% power. In fact, most of the time, they use less than 80% of their total capacity.

When we turn the AC unit on, it will start with 100% capacity. After a predetermined indoor temperature is obtained, the air conditioner will use energy only to maintain that temperature. For this, it will usually need less than 80% of its overall capacity. That also means that the electricity bill will be at least 20% lower.