How Many Watts Does A Central AC Use? (Energy Consumed)

Have you wondered why your electricity bill has shot up? You’re watching how much you use, turning off the lights and TVs, and yet the bill still seems to climb. Have you considered your air conditioning unit? The brilliant piece of tech in our houses could also be costing us a lot more than we think.

This guide will explore the number of watts your AC uses. Follow along if you’re curious about different central air conditioner wattage and what you can do to reduce it.

How Many Watts Does A Central AC Use?

Central Air Conditioner Condenser Unit Mounted on a Wall

The prices will vary depending on which state you live in and how often you use your AC unit. It also depends on what electricity tariff you’re on. For the table below, we’re using the USA average of 10.42 cents per kilowatt-hour (KWh), and KWh is the price unit of wattage used in your home.

In terms of price, we’ll assume the AC is running for one hour to work out the price.

Central AC Per TonWattage (in KWh)Electricity Cost Per Hour ($)
1 Ton3.5160.36
1.5 Ton5.2750.54
2 Ton7.0330.73
2.5 Ton8.7920.91
3 Ton10.551.09
3.5 Ton123.081.28
4 Ton14.0671.46
5 Ton17.5841.83

Naturally, for an hour, this doesn’t seem like much. For the summer months, though, this can easily and quickly add up. The size of your AC unit could be too small for your house or vice versa, which could affect how often you need to use it.

Calculating The Power Usage Of A Central AC

Split Air Conditioner on House Roof

The average 2000 square foot house in the USA will have a 3.5 Ton AC unit.

We can take into account different variables, for example, if your unit is only on ‘fan mode’ and whether or not you live in a warmer climate area.

To work out the price, using a calculation of watt power divided by 1000, followed by multiplying that result by the KWh price for every hour the AC runs.

This will give you a skewered result, though. If we take the American averages (10.42 cents, 3.5 ton AC unit for an hour), we would get this result:

12308 ÷ 1000 = 123.08 x 10.42 = $128.24

The trouble with that equation is, of course, your AC unit isn’t running for a full hour. It runs at 15-minute cycles as often as twice an hour. To give you an idea of how much we actually spend, the average house in Arizona will spend approximately $400 on air conditioning. This is also a warmer state, so this would be double the price of cooler areas. Essentially, you’re looking at a range between $250 – $550 annually on air conditioning.

What Affects The Electricity Usage Of A Central AC?

Several different factors will affect the cost of running your AC unit. Winter will see a drop in the use of the air conditioning, and the unit itself can have issues that will affect the usage. Some factors that affect the electrical input of your AC are listed below:

 Dusty Ducts/Filters

One of the reasons your AC needs to work harder is because it’s clogged. Dust is naturally occurring, and the air filters will eventually need replacing. Regular maintenance and cleaning of ducts will keep your prices down.

 Warmer Climate

Unfortunately, living in Southern states like Arizona or Texas will have higher AC prices as they keep the temperature of your house down. As mentioned, the average price of air conditioning in Arizona is $400 annually, which is based on a tariff of 12.8 cents. Installing energy-efficient air conditioners or setting timers can help reduce the prices in warmer climates.

Selective Focus on Sun with Field of Grass
 Efficiency Ratings

Most air conditioning units come with a Seasonal Energy Efficiency Ratio (SEER) rating. A SEER is the ratio of cooling output of an air conditioner over a cooling season, divided by the watt-hours it uses. If your unit has a higher SEER rating, it will be much more efficient in cooling and therefore lower your energy price. You can check the rating by contacting a specialist.

 Home Insulation

Your home’s insulation is designed to keep the heat in during cooler temperatures or out in warmer months. When your house is well-insulated, the temperature inside will remain stable, which means your central AC doesn’t work as hard. It’s a good idea to have your insulation checked, or if you don’t have any, to get some installed.

How To Save Money With A Central Air Conditioner

Thankfully, there are things we can do to control the central air conditioning wattage, which will lead to lower costs. Follow the list below for some tips to keep your house cool:

 Shade Plants

Sunlight pouring directly into your house is responsible for a lot of the heat inside. By planting light-blocking trees or plants near windows and doors, you’re eliminating the heat source and keeping the AC from working so hard. The same applies to indoor plants, which can be placed near windows to stop heat from coming in.

 Smart Thermostat

You can purchase a smart version of many appliances nowadays, and your thermostat is no different. A smart HVAC system using a smart wifi thermostat can help save up to 25% on your energy bill, and also allow you to control your AC while you’re out and about. You can set triggers that, once hit, will start and stop your AC system. It’s a no-brainer!

 Cover Windows

Windows are directly responsible for heating your home. On the long summer days, the sunlight will raise the temperature to uncomfortable levels. Reflective window films are an effective method of blocking the sunlight and reducing glare. A solar screen is also good at blocking heat. This is a polyester mesh screen installed on your window and will block up to 70% of heat transfer.

The free option is, of course, to close the curtains, but this will lead to darker rooms during the day with the lights on, leading to higher energy bills.

Sunset Captured Behind a Screen Window
 Use Ceiling Fans

Airflow into a room is important when keeping cool, and a ceiling fan will help with that. A whole house fan wont use much electricity and will work with the central AC to distribute the cooler air around your home. Smart fans are also available to help and can work with the AC by detecting the conditions and adjusting speeds accordingly.

 Keep Upgraded

A central air conditioning system is designed to last for 15-20 years. Past this, they’ll only start to increase your energy bills by working harder on an outdated system. Alongside the extra maintenance on an older system, the price will quickly increase. Consider investing in a new AC system. It’s recommended to install an Energy Star compatible system with a SEER rating of 14.5.

Frequently Asked Questions (FAQ)

Does central AC use more electricity than a mini-split?

The average central AC uses approximately 3000-3500 watts per hour, while mini-splits use 2000 watts. If you’re living in a smaller home or a cooler climate, it might be worth installing a mini-split rather than a centralized system.

Is it cheaper to run a window AC or central air?

It depends on the size of your home. A window AC unit is recommended for one room, with running costs of $30-$80 a month. If you’re planning to cool five rooms and over, a centralized system is going to be cheaper in the long run rather than cooling each individual room.

Do air conditioners use less power on low mode?

Not necessarily. A lower setting won’t cool the room any faster, rather it will cool the room to that temperature in time. A lower setting would work well if the temperature outside is lower, but indoors still needs cooling.

Do all Central ACs come with energy-saving mode?

Most modern AC systems will come with energy-saving modes, which will alternate between compressing air and a fan mode. This, in turn, will reduce its energy consumption and reduce the bill at the end of the month.


Air conditioning has become a necessity with rising temperatures and pollutants. But what isn’t necessary is the high cost of running them. Using methods aimed at aiding your AC will keep your bills down along with the temperature, and keeping a clean and working AC system keeps them efficient. So stay cool this summer, don’t get hot-headed from high prices!

Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.