Energy Efficient Refrigeration

Wes Golomb

After heating and cooling, two of the larger residential energy consuming devices are the refrigerator and freezer. It’s no wonder. These appliances are used 24/7 accounting for about 17% of residential energy consumption.

Incremental improvements in the cooling process and the thermal performance are continually making refrigerators and freezers more efficient. What makes a unit more efficient? Physics tells us that every time we convert energy from one form to another, some of it is lost as heat. Higher efficiency motors and compressors mean more of the energy is going into cooling and less heat is being generated. Better insulated and sealed units keep more room heat out. Similarly, more efficient defrosting mechanisms contribute to higher overall performance.

As a result, replacing an older refrigerator can save as much as 30% of the energy being used for cooling. Refrigerators with the freezer on top use 30% less energy than similar side-by-side models.

It makes sense that smaller refrigerators use less energy. There is less area to cool and less surface area for heat to get in.

According to the EPA, the optimal refrigerator temperature is 37 degrees F and should never go above 40 degrees F.

If you have an older refrigerator, it may not maintain a steady temperature, so it’s a good idea to put two thermometers, one in the back on top, and one in the front on the bottom, and check the temperature regularly.

Refrigerators and freezers are more efficient when they are full. The mass of the cold food actually helps to keep the temperature steady. If you have an empty refrigerator, you can put several jugs of water in it or make and keep bags of ice in the case of an empty freezer.

Obviously, the less time you keep the doors open, the more efficiently the unit will run. Cleaning out the dog and cat hair and other flotsam that collect in the back where the warm air is exhausted also helps to keep the efficiency up.

The EPA recommends refrigerators between 16 and 20 cubic feet. A 16 cubic foot refrigerator is usually enough for a household of two or three while a 20 cubic foot model should suffice for a household of four or five.

ENERGY STAR® offers the following six tips for shopping for an energy-efficient refrigerator.

1. Measure the space for the fridge. Leave at least a 1-inch clearance around the unit for adequate airflow. Don’t forget to factor in how much space the door needs to swing open in relation to adjacent walls, cabinets and appliances.

2. Consider your family’s needs, and get the right size. What is the standard size of a refrigerator in cubic feet? Fridges come in many different sizes, but the most energy-efficient refrigerators are usually 16 to 20 cubic feet.

3. Consider opting out of the icemaker and dispenser. Yes, they’re convenient and reduce the need to open the door, which in turn helps the freezer maintain a consistent temperature more easily. But they do increase a refrigerator’s energy use by 14 to 20% and usually increase the purchase cost of the fridge as well.

4. Look for a fridge with an “energy saver” switch. This switch lets you turn down or off the heating coils that prevent condensation. This enables you to better control the anti-sweat heaters in the fridge, which can lower your refrigerator energy costs by 5 to 10%.

5. Choose an ENERGY STAR®-certified refrigerator. Turn your energy-efficient refrigerator search into an easier task — make a beeline to ENERGY STAR® refrigerators. These models typically exceed general appliance efficiency standards and often qualify for rebates.

6. Compare the actual energy use number on EnergyGuide labels so you can find the most efficient refrigerator.

One of the houses I followed in my book, Warm and Cool Homes, is an off-the-grid, straw bale home built more than 20 years ago by Andrea and Jeff Burns. AA small solar array has provided their power for years. The Burns’ use a 20 cubic foot Sun Frost refrigerator and a separate freezer they purchased when they moved in. Both of these run-on DC power and use about one quarter of the energy of a comparable refrigerator and freezer of that time. DC powered cooling appliances were more efficient than similar AC models and are still currently available.

[Editor’s Note: Off-grid living does not mean you have to buy a special DC refrigerator. While the Sun Frost was the choice for years, it is actually not necessary. For many years now most ENERGY STAR refrigerators work fine off the grid, as long as you have good battery storage.

For example: My own 2-door Amana refrigerator has a bottom freezer with the ice maker inside and is working fine after 20 years, off the grid with a 3.8kW solar system. (There is not a special opening for the ice on the door, which does result is lower efficiency).

Efficiency Tips:

• The two things that consume the most electricity in a home today are water and refrigerators, so it is a good idea to keep this in mind.

• The most efficient refrigerators have two doors. A top freezer is the most efficient. However the difference is not much if you prefer the freezer to be on the bottom.

• ENERGY STAR appliances all have rating guides to show the tested performance of each model. For off-grid, choose the ones that use the least amount of electricity. For most of our readers, who are on the grid, just read the ratings and choose the most efficient one that you want. Shop for your appliances locally with confidence!

• The best way to assure efficiency with your refrigerator and freezer is to not keep the door open any longer than absolutely necessary. The point is to keep food cool and safe to consume and last longer. The motor has to work harder when it has to continually cool the unit back down.]

The common practice, from days gone by, of putting your old refrigerator in the basement or garage for keeping a few beers cold does not save any electricity or money! Why not recycle it? In NH, NHSaves will haul away and recycle your old refrigerator and freezer and pay you a $75 rebate. They will also pay up to a $50 rebate when you purchase a qualified energy-efficient refrigerator. Check out NHSaves.com for details. If you live outside of NH, you can find out about rebates where you live. In Vermont make sure to visit Efficiency Vermont at efficiencyvemont.com. In New York go to the NYSERDA website at nyserda.ny.gov or dsireusa.org. In case you have not explored information for your state on our Incentives pages 16 and 17, be sure to do so.

If you are considering replacing your refrigerator and freezer you might check out the following EPA guides.

Purchasing and Maintaining a Refrigerator

Energy Star Refrigerator Product page: bit.ly/3iPnN7N

Wes Golomb is a clean energy advocate and author of the recently published book and video series Warm and Cool Homes, Building a Comfy, Healthy, Net-Zero Home You’ll Want to Live in Forever.