When it comes to modern comforts, few appliances are as important as an air conditioner. It has become an indispensable companion for many, making it hard to image life without air conditioning. Yet, amidst the gratification it brings, a lingering question often emerges in the minds of the ecologically conscious: how much energy does an air conditioner truly consume?
As usual, there isn’t a one-size-fits-all answer. The energy consumption of your air conditioner depends on a lot of variables: the type of unit you have, the specific model, the age of the model and even the size can make a difference.
Below, we’ll dive into these different variables and give you a better understanding of how much energy an air conditioner uses. Especially if you’re looking into solar, this might make a big difference. And of course, we’ll also give you some average numbers, to give you a better idea of the context we’re working with.
Energy Consumption Ranges for Air Conditioning Units
There are different types of air conditioning units. Each type has their own pros, cons, and energy requirements. Below, we’ll focus on the four common styles when it comes to AC units: central air, window units, split system units, and portable air conditioners.
1. Central Air Conditioners
Central air conditioners can cool your whole house with a system of ducts and vents. They have different output sizes, but on average, they use around 3,000 to 5,000 kilowatt-hours (kWh) per year. Factors such as how often you run your AC and the size of your home can of course affect this number. Specifically on a 90F day in the middle of summer my home central air conditioner can use 55 kWh in a single day.
2. Window Units
A window unit is mounted in a window and used to cool a single room or a small area. These are usually less power-hungry than central air conditioners, and they average between 500 to 1,200 kWh per year. Keep in mind you would need to multiply this by the number of units you have installed in your home.
3. Split Systems
Split systems, or ductless systems, have two parts: an indoor unit and an outdoor unit. They’re used for cooling specific rooms or areas in the house, similar to window units but without the need for a window installation. The average split system uses about 800 to 2,000 kWh per year.
4. Portable Air Conditioners
Portable air conditioners are movable units that can be placed in different rooms as needed. Although they provide flexibility, they are often less energy-efficient than other types. Portable units typically consume between 800 to 1,600 kWh per year.
Overview of average AC costs
| Type | BTU | Low Annual Cost | High Annual Cost |
| Central Air Conditioner | 36,000 | $390 | $650 |
| Window AC Unit | 8,000 | $65 | $156 |
| Split System AC | 12,000 | $104 | $260 |
| Portable Air Conditioner | 6,000 | $104 | $208 |
These numbers are usually based on seasonal use – 8 hours a day during three months of the year. Also, these are rough averages and actual energy consumption can vary based on factors like usage, the size of the area being cooled, and the specific model of the unit.
Understanding these variations is the first step in figuring out how much energy your air conditioner is likely using. In the next section, we’ll talk about Energy Guides. These Energy Guides gives you more information about the energy consumption for specific models.
Understanding an Air Conditioner’s Energy Guide
Just like refrigerators, a lot of air conditioning units come with Energy Guides. This yellow tag is your key to understanding the specific energy usage of the unit you’re looking at. Here’s a breakdown of the information found in an Energy Guide:
1. Features and Model Information
On the top left corner, you’ll see the features of the air conditioner type being compared. On the right side, you’ll see the model number. This information is essential when comparing different units.
2. Estimated Yearly Energy Cost
In the middle of the guide, you’ll see a large number. This is the estimated yearly energy cost, calculated by multiplying the average kilowatt-hours the unit will use per year by the average cost per kWh across the U.S.
3. Efficiency Comparison
Just below the estimated yearly energy cost, you’ll see a bar. This bar shows the low and high energy cost compared to similar air conditioners in the same category.
4. SEER Rating
On an air conditioner’s Energy Guide, you’ll also find the SEER (Seasonal Energy Efficiency Ratio) rating. This number is a measure of the unit’s energy efficiency. The higher the SEER rating, the more energy-efficient the air conditioner.
More About SEER Ratings
SEER stands for Seasonal Energy Efficiency Ratio. It’s a measure used in the HVAC industry to describe how energy efficient an air conditioning unit is.
The SEER rating of an air conditioner is calculated by taking the total cooling output during a typical cooling season, measured in British Thermal Units (BTUs), and dividing it by the total electric energy input during the same period, measured in kilowatt-hours.
In simpler terms, the SEER rating tells you how much cooling you get (output) per unit of energy consumed (input). A higher SEER rating means greater energy efficiency, which can translate into lower electricity bills.
The specific SEER rating that’s best for you will depend on factors like your local climate, the size of your home, and your cooling needs.
New Vs Old Air Conditioning Units
The age of your air conditioner plays an important role in its energy consumption. Older units are generally less efficient than new ones, meaning they need more power to provide the same amount of cooling.
An air conditioner from the 1990s or early 2000s, for example, can use much more energy than a modern model. This is primarily because technology and standards for energy efficiency have improved over the years.
Newer air conditioning models are designed with energy efficiency in mind. They often come with higher SEER ratings. Also, newer models often include additional features like programmable thermostats or eco-modes that help further reduce energy use.
On the other hand, if you have an older air conditioning unit, replacing it with a newer, more energy-efficient model can save you money in the long run. It’s not just about the upfront cost of the unit; you also need to consider the ongoing cost of running it.
How to Use Less Energy with Your Air Conditioner
Using less energy with your air conditioner saves on electricity bills and reduces your carbon footprint, making it beneficial for both your wallet and the environment. To achieve this, it’s important to understand the different features of your air conditioner and how they impact energy consumption.
1. Energy Saving Modes
Many modern air conditioners come with energy-saving modes or eco-modes. These settings optimize energy use while maintaining comfort levels. Make use of these modes whenever possible.
2. Thermostat Settings
Every degree lower you set your air conditioner increases energy use by 6-8%. To save energy, set your thermostat as high as is comfortable for you.
3. Regular Maintenance
Regular maintenance of your air conditioner can keep it running efficiently. This includes cleaning or replacing filters regularly and ensuring the unit is not leaking coolant.
4. Proper Installation
Make sure your air conditioner is installed correctly. Proper installation can significantly affect its efficiency.
5. Window Treatments
Window treatments like curtains or blinds can keep your home cooler, reducing the need for air conditioning.
6. Proper Sizing
Air conditioners that are too large for the space they’re cooling can consume more energy. Make sure your unit is the appropriate size for your home.
7. Using Fans
Ceiling fans or portable fans can help circulate cool air, allowing you to raise the thermostat setting and save energy.
By understanding how these features and practices impact your air conditioner’s energy use, you can make smarter choices that help reduce energy consumption.
Choosing the Perfect Air Conditioner for Solar
Fitting an air conditioner for a solar system (or the other way around) can be tricky. At least when it comes to air conditioning, you’ll have the most sun peak hours when you need them the most. There are a lot of factors that affect how much energy an AC uses, but the type, age, and size make the biggest difference.
Looking at the efficiency and adjusting your habits might make a big difference in the energy consumption of your AC. The SEER ratings and Energy Guides help you make smart decisions when shopping for new units. Buying a new air conditioner might also save you money in the long run, since these appliances have become a lot more efficient in the last few decades.
If you want to know how much energy your appliances use, we’ve got a few posts to tell you more. For small appliances, a simple smart meter will work. To measure your AC costs precisely, installing an Emporia Gen 2 Vue is the best way. We’ve also written a similar guide about refrigerators.
If you’re thinking of solar, check out my Facebook group, where enthusiasts and experts ask and answer questions.