How much does it cost to run an air conditioner?
How much does it cost to run an air conditioner?
$30 – $270 average cost per month (central air)
$20 – $55 average cost per month (window AC)
Average cost to run an air conditioner
An air conditioner costs $17 to $270 per month to run, depending on the AC type, efficiency, and utility rates in your area. The cost to run a window AC is $19 to $55 per month, while running a portable air conditioner costs $29 to $50 per month.
The cost to run central air conditioning ranges from $30 to $270 per month, depending on the unit size and efficiency. In comparison, a single-zone ductless mini-split AC is more energy efficient and costs $17 to $72 per month to run.
| Type | Average cost per hour* | Average cost per month* |
|---|---|---|
| Central air conditioning | $0.12 – $1.13 | $30 – $270 |
| Ductless mini-split | $0.07 – $0.30 | $17 – $72 |
| Window AC unit | $0.08 – $0.23 | $20 – $55 |
| Portable air conditioner | $0.12 – $0.21 | $30 – $50 |
*Based on an average electricity rate of $0.15 per kWh. Monthly costs assume usage of 8 hours per day.
Central air conditioning
The average cost to run central air conditioning is $30 to $270 per month, depending on the unit size and efficiency. The unit must be the proper size for your home for optimum efficiency. An oversized unit “short-cycles” on and off frequently, and an undersized one runs continuously. Both options waste energy.
| Unit size (BTUs) | Energy consumption (Watts) | Cost per hour* | Average monthly cost* |
|---|---|---|---|
| 1 ton (12,000 BTU) |
800 – 1,500 | $0.12 – $0.23 | $30 – $54 |
| 1.5 ton (18,000 BTU) |
1,200– 2,250 | $0.18 – $0.34 | $43 – $81 |
| 2 ton (24,000 BTU) |
1,600 – 3,000 | $0.24 – $0.45 | $58 – $108 |
| 2.5 ton (30,000 BTU) |
2,000 – 3,750 | $0.30 – $0.56 | $72 – $135 |
| 3 ton (36,000 BTU) |
2,400 – 4,500 | $0.36 – $0.68 | $86 – $162 |
| 3.5 ton (42,000 BTU) |
2,800 – 5,250 | $0.42 – $0.79 | $101 – $189 |
| 4 ton (48,000 BTU) |
3,200 – 6,000 | $0.48 – $0.90 | $115 – $216 |
| 5 ton (60,000 BTU) |
4,000 – 7,500 | $0.60 – $1.13 | $144 – $270 |
*Based on an average electricity rate of $0.15 per kWh. Monthly costs assume AC usage of 8 hours per day.
If your AC unit is old, too big, or too small, consider a replacement. A new central AC unit costs $3,000 to $8,500 with installation, and the newer, more energy-efficient air conditioner can save you money with lower electric bills.
Ductless mini-split AC
The average cost to run a single-zone ductless mini-split air conditioner is $17 to $72 per month, depending on the unit size, efficiency, number of zones, and whether you are using it for cooling only. Using a mini-split for heating nearly doubles its energy consumption.
Mini-splits are extremely efficient, allowing you to cool only the spaces you’re using, avoiding wasted energy in unoccupied rooms. Compared to central AC, these energy savings can help you recoup the cost of a ductless mini-split, which ranges from $2,000 to $13,000+, depending on the number of zones.
| Unit size (BTUs) |
Energy consumption (Watts) |
Cost per hour* | Average monthly cost* |
|---|---|---|---|
| 9,000 | 440 – 700 | $0.07 – $0.10 | $17 – $24 |
| 12,000 | 600 – 1,000 | $0.09 – $0.15 | $22 – $36 |
| 18,000 | 900 – 1,500 | $0.13 – $0.23 | $31 – $55 |
| 24,000 | 1,250 – 2,000 | $0.19 – $0.30 | $46 – $72 |
*Based on an average electricity rate of $0.15 per kWh. Monthly costs assume AC usage of 8 hours per day.
Window AC unit
The cost to run a window air conditioner is $19 to $55 per month on average for a standard efficiency unit. A more energy-efficient unit costs less to run. Energy costs increase if your window unit is too big or too small for the space.
| Unit size (BTUs) | Energy consumption (Watts) | Cost per hour* | Average monthly cost* |
|---|---|---|---|
| 5,000 – 8,000 | 500 – 800 | $0.08 – $0.12 | $19 – $29 |
| 8,000 – 10,000 | 800 – 1,000 | $0.12 – $0.15 | $29 – $36 |
| 10,000 – 12,000 | 1,000 – 1,200 | $0.15 – $0.18 | $36 – $43 |
| 12,000 – 15,000 | 1,200 – 1,500 | $0.18 – $0.23 | $43 – $55 |
*Based on an average electricity rate of $0.15 per kWh. Monthly costs assume AC usage of 8 hours per day.
A properly sized window AC unit saves energy. If your window unit is short-cycling or running constantly, consider replacing it with a new model. A window air conditioner costs $300 to $1,100 with professional installation or $150 to $800 for the unit alone.
Portable AC unit
The average cost to run a portable air conditioner is $29 to $50 per month, depending on the unit size and efficiency. Portable AC units are inexpensive to run compared to other types of air conditioners but can lead to higher electricity bills if you run them constantly.
| Unit size (BTUs) |
Average power consumption (Watts) |
Cost per hour* | Average monthly cost* |
|---|---|---|---|
| 8,000 – 10,000 | 800 – 1,000 | $0.12 – $0.15 | $29 – $36 |
| 10,000 – 12,000 | 1,000 – 1,200 | $0.15 – $0.18 | $36 – $43 |
| 12,000 – 14,000 | 1,200 – 1,400 | $0.18 – $0.21 | $43 – $50 |
*Based on an average electricity rate of $0.15 per kWh. Monthly costs assume AC usage of 8 hours per day.
Factors that affect the cost to run an AC
Several factors influence the cost to run an air conditioner, including the unit size and efficiency, utility rates in your area, how many hours per day you run the unit, and your home size and condition. Let’s explain each of these factors:
Unit size
The bigger your home is, the bigger your AC and electric bill will be. Air conditioners are measured in tons. Each ton has 12,000 BTUs of cooling capacity and can cool approximately 500 square feet of space. However, other factors in addition to your home's square footage affect the required AC size.
To ensure you get the correct AC size for your home, have a professional HVAC installer perform a Manual J load calculation. Rather than relying on square footage alone, this calculation considers your home’s layout, insulation, sun exposure, climate, and other factors to find the perfect system size.
SEER rating
Seasonal Energy Efficiency Ratio (SEER) ratings are a measure of how efficiently your air conditioner converts electricity into cooling power. Units with higher ratings will use far less electricity. In fact, studies show an average 6% to 10% decrease in energy consumption per point increase in SEER.
Simply put, higher SEER = lower utility bills.
Since 2023, both SEER and SEER2 efficiency ratings may appear on labels. SEER reflects cooling output relative to the energy consumed, while SEER2 uses updated testing conditions for a more accurate picture, especially in warmer regions.
Utility rates
Utility rates vary from state to state, but the average cost of electricity in the US is $0.14 to $0.16 per kilowatt hour (kWh). To estimate your air conditioner’s running cost, multiply the kWh consumption by your local electricity rate per kWh to get the cost for that period.
Hours of usage
The longer you run your air conditioner, the more you'll pay in energy costs. Limiting your usage when possible can save you money on your electric bill. Keep in mind that some utility companies charge higher rates during peak hours or on weekends, increasing your running costs.
Home’s condition
Your air conditioner is not the only thing that increases utility costs. Older houses often lack proper insulation and have leaky ductwork, allowing warm air inside. This forces your AC to work harder to maintain the interior temperature.
Cut down on utility costs in your older home by hiring a professional insulation contractor or ductwork company to make upgrades.
Air conditioning energy cost calculator
Keeping cool comes at a cost—with air conditioning accounting for more than 50% of summer electric bills in some areas. Understanding your air conditioner’s energy usage can help you plan your monthly utility budget.
Use this formula along with the details below to calculate your air conditioner’s monthly running cost:
Watts x Hours used per month x Electricity rate ($ per kWh) ÷ 1,000
Here are some common terms to help you get started:
Watt: A Watt measures how fast you transfer or use energy. The higher the Wattage, the faster your AC eats through electricity. 1,000 Watts is known as a kilowatt (kW).
Kilowatt-hour (kWh): A kilowatt-hour (kWh) measures the rate and duration you’re using electricity. 1 kW x 1 hour = 1 kWh. Since electricity bills use kWh to measure usage, understanding this helps you estimate your electricity costs and better manage your budget.
BTUs: The British Thermal Unit (BTU) measures an air conditioner's cooling power. The more BTUs, the more cooling capacity.
Tonnage: Air conditioner sizes are measured in tons. One ton is equal to 12,000 BTUs of cooling power, so the larger the tonnage, the more BTUs a unit has. The average 3-ton air conditioner has 36,000 BTUs of cooling power.
How to save money on your cooling costs
While you can’t control the utility rate in your area, you can install an air conditioner that consumes less electricity, saving you money each month. Additional tips for saving on your cooling costs include:
Thermostat settings & upgrades: Set your thermostat to 78° F or higher to reduce AC runtime and install a programmable or smart thermostat to adjust temps for better efficiency. A new thermostat costs $160 to $450, including professional installation.
Insulation upgrades: Attic insulation costs $1 to $4 per square foot and can save you 10% to 20% on your heating and cooling costs.
Ductwork upgrades: Seal or replace any leaky or oversized ducts so cooled air doesn't escape before reaching vents. Replacement ductwork costs $25 to $55 per linear foot or $270 to $500 per duct run, including labor and materials.
Ceiling fan installation: Ceiling fan installation costs $250 to $700 to help circulate air and supplement air conditioning.
Air conditioner maintenance: An annual AC tune-up costs $70 to $200 and can reduce cooling costs, minimize repairs, and extend the life of the unit.
Consider getting a professional home energy audit to identify the most cost-effective ways to reduce your home's energy usage and lower your utility bills. A home energy audit costs $200 to $600.
FAQs about the cost of running air conditioning
How much electricity does an air conditioner use?
An air conditioner can use as little as 440 watts per hour to as much as 7,500 watts per hour, depending on the AC type, size, and efficiency. The climate, thermostat settings, and hours of usage also impact the total electricity consumed.
Central air conditioning uses 800 to 7,500 watts per hour.
A ductless mini-split air conditioner uses 440 to 2,000+ watts per hour.
A window AC uses 500 to 1,500 watts per hour.
A portable AC uses 800 to 1,400 watts per hour.
Do old air conditioners cost more to run?
Yes, old air conditioners usually cost more to run compared to newer, more energy-efficient models. Upgrading to a newer, energy-efficient air conditioner can result in long-term cost savings on energy bills.
Is it cheaper to run a window AC or central air?
Window units are cheaper to run than central air. However, they can only cool a small space.
Is it cheaper to leave the AC on all day?
Keeping the AC on all day is more efficient if you maintain an indoor temperature of 78°F or higher and your home has good insulation. Quick on/off cycles without letting temps fluctuate waste more energy. You shouldn’t cool an empty home for hours, either. Instead, use a programmable thermostat to find the right balance.
Do air conditioners use more electricity than fans?
Yes, air conditioners use more electricity than fans. Most air conditioners use thousands of watts to cool the air, while ceiling fans use between 50 and 100 watts to simply move the air around. Using a fan with your air conditioner can improve efficiency and reduce monthly utility bills.
Questions to ask an AC contractor
If you still have questions about your existing air conditioner’s efficiency or have decided it’s time to install a new air conditioner, reach out to an AC installation company near you. Find a reputable contractor with good reviews on HomeGuide and ask these important questions:
What size/tonnage AC unit do you recommend for my home?
What is the SEER rating and expected efficiency of the unit you're proposing?
Is my current AC system sized appropriately, oversized, or undersized? How do you determine the correct capacity?
What additional features do you recommend, like programmable thermostats or smart controls to improve my energy efficiency?
Does my home need new ductwork or can you repair the existing ducts?
Does the house need better insulation?
How much will the new unit installation cost and what is included in that price quote?
Using our proprietary cost database, in-depth research, and collaboration with industry experts, we deliver accurate, up-to-date pricing and insights you can trust, every time.