Understand your fridge’s energy consumption and find ways to reduce it
Fridges are usually one of the largest energy users in a home. Since they are (almost) constantly running, they use a significant amount of power. This makes the refrigerator one of the many reasons for using solar power as an alternative energy source in your home. But exactly how many watts does a fridge use?
To determine that, you need to know the difference between kilowatts (kW) and kilowatt-hours (kWh). A kW is the unit that measures the rate of power usage, whereas kWh is a calculation that determines the amount of energy used. When you pay your electric bill, for instance, it is based on kWh.
With that in mind, let’s dive in!
In this article:
- Average electricity consumption for a refrigerator
- How to calculate fridge energy use
- Factors affecting fridge energy consumption
- Ways to reduce fridge energy consumption
- Making the best of fridge energy use
- Frequently asked questions
Average electricity consumption for a refrigerator
The average refrigerator wattage is between 300 and 800 watts (or .3 to .8 kW). Age, size, and how often the refrigerator runs (its runtime or usage) can determine whether a fridge is higher or lower on the wattage scale. So, you’re looking at roughly 2.4 kWh to 6.4 kWh per day if the fridge runs an average of eight hours per day. This is a rough estimation based on the compressor runtime, which typically runs 80-90% of the time. The climate, how full the fridge is, how long the door is open, blocked freezer air vents, and dirty gaskets or condenser coils can all impact the actual refrigerator run time.
Although a fridge uses a lot of energy, some appliances use even more. For comparison, an average air conditioning unit can use roughly 8 kWh per day just running during the daytime.
How to calculate fridge energy use
With several different types of energy units, such as watts, volts, and amps, it may seem difficult to find out how many kWh a fridge uses. Don’t worry. All these units work well together once you know the formulas.
Finding the wattage of your fridge
If you look at your fridge’s label, you likely won’t see a wattage measurement. Instead, you’ll find amps and volts. But with a simple formula, you can use those numbers to calculate the wattage of your fridge.
Volts x Amps = Wattage
So, a fridge with 120V and 4A will have a wattage of 480 or .480 kW.
Determining daily kWh usage
To calculate how much power an appliance is using, try the following formula:
Watts x Daily Hours Used / 1000 = Daily kWh
For example, a 500-watt fridge running the average eight hours per day would use about 4 kWh per day. (500 x 8 / 1000 = 4). This number may be lower for more modern units, which can run on a cycle and have a lower run time. Dividing by 1000 at the end is crucial since a watt is 1/1000 of a kW.
Estimating monthly and annual kWh usage
Figuring out how many kWh your fridge uses per month (and year) is a piece of cake once you calculate its daily usage. All you need to do is multiply that daily usage by the number of days in a given month, or 365 for the annual usage.
For example, a fridge with a 2.4 kWh daily use will use 72 kWh in a 30-day month and 876 kWh per year. That number can range from 400-1000 kWh/year, depending on the efficiency. To compare, the average kWh of an entire household in the United States is 899 kWh per month, according to 2022 data from the U.S. Energy Information Administration.
Factors affecting fridge energy consumption
As with any appliance, there are many brands, styles, and sizes. Some houses use high-capacity French door refrigerators, while others use more compact models. These factors change how much energy a refrigerator consumes over a day or its lifetime.
Size and capacity
When you have a larger refrigerator, it requires more power or kWh. That’s because it has to cool a larger volume (and presumably more stuff), which requires it to draw additional power for more cooling. The opposite is true for smaller fridges — they don’t need as much power since they’re cooling a smaller space.
According to the Department of Energy, the most energy-efficient fridge size is 16-20 cubic feet. Energy Star has recommendations on the most energy-efficient refrigerators.
Age and efficiency rating
Older refrigerators tend to use more energy than newer ones. There are a few reasons for this, but generally, older technology is less energy efficient, and appliance parts may be worn out and not operating at full capacity.
Efficiency ratings help consumers see how efficient a refrigerator is compared to similar units. You can look at a fridge’s Energy Efficiency Index (EEI) number as an indicator — the lower the number, the more efficient it is.
Location
Believe it or not, where you have your refrigerator placed in your home can impact how many kWh it uses. To ensure your fridge works at peak efficiency, keep it away from hot appliances, like ovens, and direct sunlight. You should also leave space around it so the condenser coils can circulate air.
Energy Star certification
ENERGY STAR® is an independently verified, government-backed program that determines efficiency ratings for products and practices. It’s overseen by the Department of Energy and the Environmental Protection Agency (EPA). The EPA sets energy efficiency specifications, and companies with products that meet the requirements can choose to display the ENERGY STAR logo. Refrigerators, washers, dryers, thermostats, dishwashers, and more products are all eligible for this certification program.
Ways to reduce fridge energy consumption
Although we run our refrigerators constantly, there are a few steps we can take to help them use less energy without unplugging them altogether.
Proper refrigerator maintenance
Maintaining your refrigerator is critical to reducing its energy usage. The easiest maintenance you can do is clean the door gaskets to keep a tight seal. Ideally, you want to do this with warm water and soap at least twice a year.
Another twice-yearly maintenance task is to clean your refrigerator coils.
These are located on the back or under your fridge, so you’ll need to pull the fridge away from the wall. After unplugging the fridge, use a coil brush and/or vacuum to remove debris from the coils. Doing this helps your fridge run more efficiently.
Optimal temperature settings
A refrigerator set to the coldest possible temperature will use much more energy than one set at a middle point. The most energy-efficient temperature setting is between 35 and 38 degrees for a fridge and 0 to 5 degrees for a freezer.
Efficient usage tips
Everyday habits can make a world of difference in the energy efficiency of your refrigerator. A few simple things you can do are keep the doors fully shut whenever you can, keep the fridge full to maintain its temperature, and don’t put hot food in the fridge. Anytime you make the fridge’s internal temperature higher, it has to work harder to get the temperature back down.
Defrosting
Defrosting can also help improve energy efficiency. If there is a large ice buildup in the freezer, your fridge has to use more energy to keep everything cool. If you have a manual defrost model and see ¼ to ½ inch of ice, it’s time to defrost.
Upgrading to an energy-efficient model
Even if your 20-year-old workhorse refrigerator is still operational, that doesn’t mean your household couldn’t benefit from an upgrade. Getting a newer, energy-efficient model can save you a lot of money. There are even rebates for energy efficient refrigerators that vary state by state. Energy Star has a calculator to determine how much you can save by upgrading.
Upgrading from a 2001-2010 model with a freezer on top and average size and electricity usage, for instance, can save over $140 across five years and reduce carbon pollution by over 411 pounds at the same time.
Making the best of fridge energy use
Understanding how much electricity your fridge uses is important for maintaining an energy-efficient household. Knowing your fridge’s energy usage can also help when calculating what solar and storage solutions you’ll need to run it, along with other appliances. Keeping your refrigerator clean, full, and away from heat sources can help keep it running at its best for years to come.
Or, when the time is right, you can upgrade to save money and reduce your environmental footprint at the same time.
Frequently asked questions
How many kWh does a fridge use per day?
To determine how many kWh your fridge uses in a day, you can use this calculation:
watts x daily hours used / 1000.
That formula gives you your daily kWh usage. The average rate for 300 to 800-watt fridges is between 2.4 kWh and 6.4 kWh.
How many kWh does a mini fridge use?
Since they are smaller than a traditional fridge, mini-fridges use significantly less energy. The U.S. Department of Energy regulates that compact refrigerators with automatic defrost have a maximum energy use of 259.3 kWh/year. Energy Star-certified compact refrigerators usually use 200-400 kwH/year.
How much does a fridge cost to run per month?
How much it costs to operate a fridge depends on the type of fridge you have and how efficiently it runs. The energy cost also depends on where you live, as some places have higher costs than others. According to the U.S. Energy Information Administration’s 2020 Residential Energy Consumption Survey (the most recent available), the average refrigerator expenditures per household using a refrigerator were $116 per month.
How can I calculate solar requirements for a refrigerator?
Let’s assume a single solar panel can produce roughly 2 kWh per day — given a 400 watt panel multiplied by 5 peak sun hours — depending on location, panel size, and weather conditions. So, take the average daily fridge electric usage from above, between 2.4 kWh and 6.4 kWh, then you can calculate that it takes anywhere from about 1.2 to 3.2 panels to power a fridge.
