The recommendation to ditch the second fridge is a key. I have seen far too many environmentalists harboring a second and unnecessary fridge or freezer in the garage or basement!

Concerning buying an Energy Star fridge, great advice but note that not all Energy Star refrigerators are equal -- so when shopping for one look at the DOE energy tags and pick absolutely the most energy efficient one.

One easy way to keep the fridge full is to fill empty milk containers or other large gallon-sized containers with water and keep them in the refrigerator, removing them when necessary.

I see the "clean the coils" tip all the time, but I also recently read in a Sierra Club's Mr. Green column that it is a myth that cleaning the coils has an impact on the fridges energy efficiency. Anyone have some insight on whether or not cleaning the coils really does help?

I always read that filling your fridge too full (more than 3/4) prevented proper air circulation. Is there any truth to that?

We ditched the second fridge that came with our house shortly after we bought it. Killed me a little to toss something that worked fine (a junk man came and picked it up anyways, hopefully he could resell it) but it was old (in-efficient) and was out in our garage - keeping soda cool in the summer for cookouts is just NOT that important.

We just cleaned our fridge coils last week, after 2 years in the house. Uh oh! Don't know if it helped or not, just figured it couldn't hurt and the fridge fix-it man recommended it when he came to fix the ice machine.

I'm not sure about this one. Doesn't this calculation completely ignore the cost of cooling the items initially? Not only that, while the percent of cooling lost with each door opening may be reduced, the total amount of cooling lost may be the same.

I really don't see how this can be true from a thermodynamics point of view unless it has more to do with the loss of air volume rather than the increase in thermal mass.

Adam - thank you for the follow-up. I was only able to find one study and it is from 1993, so I don't know if it applies well to newer models:

http://www.homeenergy.org/archive/hem.dis.anl.gov/eehem/93/930108.html

I agree that old refrigerators are often old and inefficient and that in general there's value to declutter garages and basement, but I often wonder how wise it is to just junk something for the sake of improved efficiency when that something may have plenty of life left (especially if you don't know WHERE it's going). That device, though old, still took energy and resources to build.

It's akin to people replacing all their incandescent light bulbs in their house (and tossing them) with compact fluorescent even though many of those bulbs may still have months to years of life left (especially if it's a light that is seldom used). I'm a much bigger advocate of using things until you have to dispose of it and then replacing them with a more efficient successor. No doubt there is a tipping point where energy saved is worth more than the energy it took to make the device and the cost of properly disposing or recycling the materials. But consider the carbon production of having some guy drive his big gas-guzzling truck to your house just to haul away an appliance.

I am a big advocate of donating to other people (which seems like a good way to get rid of old clothes, appliances, etc), but if you think about it, if you are giving an old inefficient device to someone else to just rid yourself of it, aren't you just pushing off your carbon footprint on someone else? I guess if you give them something that is necessary (like a refrigerator) then it's probably worth it, but donating all your old incandescent light bulbs to someone isn't. The perfect solution would be to recycle all or most of what is replaced.

In any case, I think most people could just save a lot of energy if they simply unloaded their extra refrigerator when it's not necessary and unplug it.

Slate on fridge replacements:
http://www.slate.com/id/2198670/

Just a Thought on the "Second Fridge"...If you have the room and are any kind of survivalist or just someone that WANTS to be ready for any type of emergency, you may want to keep that second fridge...JUST DO NOT RUN IT...if you have the room for it, if the magnet is in tact on the door, you can store Dry foods for a VERY long time keeping bugs from getting into them, if they're in a controlled environment they will likely stay at a nearly constant temp inside, if notthing else, just extra storage just keep it UNplugged no waste of energy that way. Quite possibly if you have an extremely OLD fridge with the pull down handle that's made of heavy guage steel, it may also be somewhat fire resistant. Can anyone give proof or disproof of any of this...Grandparents info passed down over the years

I will look closer to these energy star fridges available today. Thanks for the tip, and a nice website resource with blog.

Instead of milk jugs filled with water, I just keep a case of white wine in the fridge! Takes up space, and I never have to take the time to chill a wine.

I don't know much about thermal densities and whatnot, but it seems like simple logic to me that a jug of water isn't going to escape from your fridge every time you open the door.

I've been preaching to my parents about the wastefulness of the "extra fridge" for a long time. Believe it or not, at one point, they had SIX (6!) refridgerators and/or freezers at one time!! I'm not kidding! Two were fully stocked typical fridge/freezer combos (one upstairs in the kitchen and the other downstairs in the kitchenette), one was a full size upright freezer (fully stocked as well), one was another full size upright freezer stocked with donated meat belonging to the soup kitchen my stepmom manages, there was another upright combo in the garage to store drinks, and there was a half-size chest freezer in the guest bedroom (stocked to the hilt)! All of this for 3 people in a small 3 bedroom house.

Fortunately for our planet, they are now down to two combos and the small chest freezer.

These are also the same people who have no less than NINE working telephones, excluding their cells! Their house sounds like it's gonna explode every time someone calls! But don't get me started on that one.

Needless to say, they do not receive the TerraPass newsletter.

The gallon of water illustrates this well for me. If the refrig is half full, then an open door means allot more air rushes out. The new hot air will need to be cooled again. In the summer the house it cooler, oh well. :-) But in the winter you are CHOKED 2 directions. :-(

If you overload your refrig, then you spend too much time shuffling things around. I hate that game. Jugs go to the floor and then they are dirty, etc. If you have a newer model with solid glass shelves, the refrig would hold the air in better than those old style wire shelves.

If you're stuck with wire shelves, you could add plastic to the bottom 2 shelves. Maybe you could position a long skinny tupperware container, so the air has less room to scoot out. Think of it like a DIKE - to block some air movement. It's a good container for veggies or small containers.

Someone above wrote:
Doesn't this calculation completely ignore the cost of cooling the items initially? Not only that, while the percent of cooling lost with each door opening may be reduced, the total amount of cooling lost may be the same.
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The problem is: How long do the water-filled jugs have to be used? Should you keep them 2 days or 5? Does the small payback come after 4 days? How many jugs are needed? In my refrig I could turn jugs on their side with only half full, then place on a nearly empty shelf, to act an air dike.

When done, you could use this cold water outside the refrig, but you may not wanna drink it. Turn the AC off and sit next to it! The possibilities are endless.

Challenge: some engineering class needs a competition to design experiements where they test this problem. As I discussed, the different kinds of friges make a difference in the outcome. Two half gallon jugs, tall and skinny, are lots better than the gallon jug. BUT HOW MUCH BETTER??

I noticed that no one mentioned looking for a fridge with a quick access door in front.

My fridge has a small door that opens to an enclosed shelf, so that if there's something that I'm constantly opening the fridge for, like drinks, I can use that and avoid opening the entire door. I love it - but I've only found one model that features it.

I agree with Jake. I cant understand how the idea works from a thermodynamics perspective? anyone can help?

I am no thermodynamics expert ... but I would disagree.

Firstly, the analysis ignores the "energy cost" of cooling this buffer in the first place.

Second, is this "buffer" really a bugger at all? If we measure the "cost" of opening the fridge door in terms of heat loss, then its gotta be the same in both cases. Only when the fridge is fuller, the overall temperature reduction of the objects inside is lower simply because of the higher mass that is present; and higher masses always need more heat input or output for the same temperature change as lower mass.

third, it goes against what our intuition probably tells us. Refrigeration, always, independent of mass, eats up energy. It seems a little weird then, that more refrigeration, (a way of looking at keeping more items cool) should
consume lesser energy. i mean ... transporting 5 people in a single automobile always consumes more energy than 2 people; washing 4 kg of clothes in a single dryer takes more power than 2 kgs.

Well, I'll just ask my professor next week, haha.

Buying an energy star refrigerator and keeping the coils clean are two easy contributions you and your family may make when choosing to go green.

Does anyone know which is better energy-wise when opening your fridge:
1. Get a jug of milk out and CLOSE the fridge door while you pour your drink. Then you open the door again to put the jug back.
2. Get a jug of milk out of the fridge and keep the door open while you pour the drink.
I'm sure the amount of elapsed time would matter (the amount of time it takes to get your cup, grab some ice and then pour your drink). What are your thoughts?

My in-laws think that by only opening the fridge door to get out a drink once, instead of twice, they are better off. They think the air sucked out each time the door is opened causes more of an energy pull than leaving it open while they fill their glass. You can guess that this has been a fun family discussion...

I somehow missed this one the first time around, so am weighing in late, but this is actually a pretty simple model.

First, while there is a cost to getting things down from room temp to refrigerator temp, there's little cost to keeping them there. The fridge is sufficiently well-insulated that it will hold its interior operating temperature for quite a long time even without power (hence the admonition not to open the fridge when the power goes out--if you keep it closed it may hold everything for up to several days without spoilage, depending on the temp outside the fridge.) This is the principle behind the idea of putting the fridge on a timer that cuts its power overnight. It really doesn't need to run the compressor very often when it's not being opened.

Second, every time the door is opened, the (denser) cold air rolls out onto the floor. I don't know how much difference it makes whether your shelves are solid (glass) or wire, but how long the door is open is probably a pretty big factor. The air doesn't get "sucked" out when you open the door, but warm air from the room is going in while the cold air from the fridge falls to the floor and rolls across your ankles. This takes time. Plus the longer the door is open, the more the warm room air is getting cooled off by the contents of the fridge--warming them up and sending more cold air to the floor.

This is why keeping the fridge stocked is more energy efficient. The less total cold air volume in the fridge, the less warm room air gets in when you open the door, and the less energy it will take to cool that air. There is a tipping point where the circulation is blocked if you have too much in the fridge, but I suspect the effect has less to do with the energy cost than with the fact that items stored far from where the cool air comes into the fridge may not be kept at a safe temperature.

The air exchange is also why chest freezers are so much more energy efficient than upright; the (denser) cold air barely exchanges with room air at all when you open the chest freezer.

Third, unless your refrigerator's compressor coils are routed to outside the house, opening the fridge is always going to have a net warming effect on the inside of your house, winter or summer. All of the energy that is removed from the warm air in the fridge is exhausted back out into the room from the coils; that's how the fridge works. But the heat produced by the compressor is added to that. So every time your fridge has to cool down a warm mass of air, you get back all the heat that was in that air plus the amount of heat generated in separating it out. So you always lose, winter or summer. Worse in summer because you're paying to put extra heat into the house and then paying again for air conditioning (which works the same way as the fridge, except that the coils are installed outside the house to exhaust the heat outdoors) to take it out. The warmer your house is, the more extra energy will be used in cooling that warm air back down to fridge temp.

Thanks sincerely for your input, folks! It is very helpful.

Instead of ditching a second refrig that still have years of useful life left and one that you only use a few times a year like at Thanksgiving or family BBQ to keep drinks cold, why not unplug it when not in use. Is there any harm in letting a used frig sit?