Five Percent: Conserve Energy

Climate Change Is Important: Energy Conservation is the First Step


May 24, 2009

Refrigerator Efficiency: Change The Light Bulb

Category: Conservation,Household,Save Electricity,Tips – Tom Harrison – 12:33 pm

pg24_refrigeratorThere are a lot of tips out there about how to use less energy with your refrigerator — the ones I have seen aren’t wrong, but I think they can be misleading. I would never argue that improving efficiency is a bad thing, but it’s important to keep the big picture in mind.

According to the US Energy Information Agency (EIA), refrigeration accounts for only 5% of household energy use.

So, this being the real picture, my blog is all about how the little changes we make can indeed add up. And I encourage people to do whatever changes they can — there are plenty out there, to be sure!

So with the big picture in mind, here are some of the factors to think about relating to refrigeration.

The Big Picture (of Refrigeration)

You may have read that adding jugs of water to take up space and act as a “buffer” is a good idea, and it is (unless you do what I saw a friend do).

There are several reasons why adding water bottles to the fridge (or extra ice to the freezer) make it more efficient. First, solids and liquids are better at storing heat energy than air because they are more dense, so they act as a “buffer”. Additional items in the fridge also mean that when the door opens, the vortex of warm outside air rushing in is disrupted — the things that are already cold stay put, especially if the jugs are in the front.

But there are some questions to consider before loading up on water jugs. First, the fridge has to work to get those jugs of water from whatever temperature they are at to the cooler temperature inside. I saw a friend who filled a jug of water to put in the fridge, but happened to have the water faucet on the “middle” setting — he ended up putting warm water in. Whoops. And how full is the right fullness — if you take the water out every time you shop, then put it in a few days later, it’s hard to say that there’s a net benefit.

Bigger Picture

The Real Big Picture

The Real Big Picture

The bigger picture may be far more important, though.

The real issue is that opening the door lets out cold air and lets in warm air. The design of the refrigerator creates a suction when the door is open that results in a rush of air, so better to have the door open for 20 seconds once than 10 seconds two times. Sure, reducing the amount of air lost is good, but by far the bigger win comes from reducing the number of times the door is opened!

When I come home from shopping, I take stuff out of the bags and arrange it on the counter based on where it’s going into the refrigerator — take out any of the leftovers that won’t get eaten, replace with new food in the right place, then close the door. Same deal when preparing food — a little planning can reduce the number of times you open the door.

Increasingly Bigger Pictures

Bigger picture still: have you cleaned the coils lately? The fridge works by compressing freon (with an electric motor that uses energy), then releasing the pressure inside the fridge, which makes the coil cold — the coil then collects heat, which goes to the outside of the fridge, underneath, usually, where a fan blows the heat into the room. The coils have aluminum fins that draw the heat out of the coils, but tend to collect dust bunnies that act like fur coats. If enough builds up, dust clogs the vents in the front, leaving lots of heat behind the fridge. Not cool.

So big picture number one: if the coils are covered in dust or clogged up, the heat builds up and the fridge has to work harder to keep it cool.

Do you have an old fridge? Or are we actually talking about the spare refrigerator in the basement or garage? How efficient is it? Did you buy the “SUV” model of refrigerator but realize you could use something smaller :-) If your refrigerator was made in 2001 or earlier, a new Energy Star refrigerator will use 40% less energy. After some thinking, we figured that we didn’t really use the (cheap, inefficient) deep freezer in our basement, did a better job organizing the main refrigerator, and turned the old one off completely (which I believe comes out to 100% savings).

Bigger picture number two: is it better to make an old or inefficient or unneeded refrigerator more efficient, or may it be better to replace it or retire it completely?

And just to remind: the biggest picture here isn’t the refrigerator — it’s probably your house’s insulation or other electrical use.

2 Comments

  1. could you please help settle a disagreement? Which uses more energy: Lights left on in vacated rooms (my husband’s habit) or a refrigerator door left open while taking several items out or putting several in at the same time? ( my habit). Thanks for helping settle an ongoing disagreement. :) Mary Beth

    Comment by Mary Beth — April 10, 2011 @ 7:00 pm

  2. The question is, which wastes more energy. If you assume you’re using (and not wasting) energy by cooling your food and you are not just leaving the door open for fun, and you assume that lights left on in empty rooms serve no purpose (and are therefore wasting), then there’s your answer.

    Perhaps the exercise left is to figure out how much. Calculate in Watt Hours. Number of lights X watt rating X number of hours on = watt hours for lights.

    Tom

    Comment by Tom Harrison — April 12, 2011 @ 9:55 pm

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