How Do You Add Insulation to a Refrigerator? : LUSENET : Archives- from C-side : One Thread

How Do You Add Insulation to a Refrigerator? : LUSENET : Countryside : One Thread

Okay, I've been doing a lot of reading about alternative energy resources and one of the things they all talk about is cutting down on the demand. Then they tout the more efficient appliances, at huge prices, and suggest you start by buying something like that. All the refrigerators and freezers highlight the EXTRA INSULATION they have. So, can't a person super-insulate their existing appliances? And does anyone know how to do that? What kind of insulation to use, etc? Thanks,

-- Deborah (, May 05, 2001


Thats what that almost totally handbuilt Sun refrigerator RealGoods used to carry (maybe they still do?) was, just a superinsulated box which then could be cooled with a smaller compressor. Took very little energy so could be powered by solar, also small interior and very expensive. The hardest thing about doing it yourself on regular fridge is that they have the heat dissipating coils mounted right against the back or bottom of the fridge. The coils and the compressor need to be exposed to the room air. Otherwise I guess one could glue insulation board to outside of the fridge. If one had the ability and tools to safely discharge the coolant then extend the coils out from the fridge and maybe reroute and remount the compressor above the fridge (like the old pre WWII fridges which were extremely efficient even without lot of extra insulation- post WWII fridges were made for style first, efficiency last), then superinsulate the box and recharge the coolant, you could vastly improve the efficiency of the fridge.

By way auto defrost is just heater mounted in fridge walls. It cycles every once in a while to "defrost". This cuts down on energy efficiency (you have compressor having to work harder to make up for heat from defrost). I kind of regret not buying one of those old pre WWII fridges with top mounted compressors in good condition few years ago when I had the chance. Some lady antique dealer ran price up on me and I didnt really need it so dropped out of the bidding at around $50. Guess they are collectable in some circles simular to the pre WWII wringer washers although frankly cant figure what antique collectors do with such things. They for sure dont use them for their intended function. Guess just period decoration.

-- Hermit John (, May 05, 2001.

You can try it, but not sure it would do much good. There are a couple of problems that needs to be overcome. 1) The seal in the door is a weak link and will leak, 2) If I remember my physics correctly, heat (cold) will escape the easiest route. In other words, if you leave one area uninsulated, that is the path heat will use. As HJ pointed out, the coil area will be the weak link.

I sorta remember an article, maybe Backwoods, that had an article on building a super insulated box and moving the cooling mechanism from an old refrigerator. Perhaps someone else can recall more of the details or search their WEB site.

-- Lynn Goltz (, May 05, 2001.

I too have always thought of super-insulating a fridge. When I worked in the bar industry, walk-in coolers for the beer and wine were nothing more than a super-insulated box with a door and what amounted to an air conditioner mounted inside with the compressor and coils isolated away from the box.

One would think that if a simple fiberglass blanket for the hot water heater makes a noticeable difference, then wouldn't a rigid foam skin attached to the outside of the fridge do the same? We don't have to go from the barely efficient to absolute efficiency before we try something do we? Cosmetics might play on this one, but a pleasant veneer could be accomplished with several products, paneling, tile board comes to mind first off.

Of course, putting a layer of say 4" foam around the entire fridge (and allowing for the coils and/or compressor breathing problems) would make you one pudgy fridge. It would increase in size by 8"+ in all directions. The new "cabinet" of insulation could have its own door, making the door seal on the fridge less of a problem. And I was thinking that moving air might aid in the coil/compressor breathing problems, say a very low voltage waffle fan drawing or blowing air over/across the equipment.

With the fridge being the most expensive appliance to operate, this might pay for it's self in no time - same for freezers I would imagine.

-- Willy Allen (, May 05, 2001.

Willy, the fan idea is a good one. If you lower the air temp over the coils (moving vrs. stagnant air) the overall efficiency should be improved. Maybe you could hook it up to come on when the compressor is turned on with a simple relay. One word of caution, in the winter I don't see a problem; however, if you air condition you might notice a slight air temp increase near the refrigerator. (The heat produced would be the same, just that one would feel it more with the moving air.)

-- Lynn Goltz (, May 05, 2001.

Increasing the insulation sounds like a good idea but you would have to be sure that the outer surfaces of the cabinet are not part of the heat radiating system, as I have seen on some chest type freezers. Considering that the coils have to radiate the heat away it might be easier to increase the efficiency of this process by draping an old towel or somesuch over the coils and keeping the towel wet, maybe by a water drip system or even wicking up from a trough at the floor level, this would however increase humidity in the room which may or may not be a good idea. If you try this be sure the metal of the coils is well painted to avoid whatever problems such as rust that might come from being continuously wet.

-- john hill (, May 05, 2001.

Just a quick suggestion, which probably is not attractive to a lot of people. In the winter, assuming that you need to heat your house, the inefficiency of the 'fridge is not as big a deal as in the summer. All the waste heat from the fridge goes into heating the house (assuming the fridge is located indoors.

This method of heating the home is essentially just as efficient as heating with electric resistance heat (so is the waste from any electric appliance, lights, etc). Obviously, the electricity will cost you money, and you may prefer to heat with wood, or some other source. A heat pump is much more efficient than resistance heat, or waste heat from the fridge, etc. But at least, the waste heat is HELPING to heat your house.

On the other hand, in the summer time, the waste heat is STILL heating your home, and that's the last thing you need. That's when a high efficiency fridge pays off the most. Especially if you're using an air conditioner.

There are a couple of ways to deal with this, I think, other than insulating your fridge (I'm not suggesting these two methods are better, just different).

One way would be to put your fridge outside the house for the summer. This is obviously a lot less convenient. Another way woudl be to put vent the fridge's waste heat outside, during the summer.. This would be a practical way to get rid of it. Whether it's worth the effort or not would depend on your individual situation. I personally almost never need air con, so I haven't put any energy into this.


-- jumpoff joe (, May 05, 2001.

backwwods Home magazine,, their website, back issue (not sure which one) has a very good article on making your refridgerator more effecient, including adding more insulation

-- stan (, May 05, 2001.

Good points Joe. Is a fridge not a heat pump? If I put a bucket of water in my fridge will not the heat released from the fridge coils plus the heat released from the refrigeration unit but greater than the equivalent resistance heating for the same amount of consumed electricity?

-- john hill (, May 06, 2001.

Make sure your frig has the coils in the back if not they are probably in a side and top, which you wont be able to put insulation on it

-- Wittey (, May 08, 2001.

If I understand your question, John, I'm afraid not. Yes, a refrigerator is a form of heat pump, but since it takes heat from the kitchen, and adds heat to the kitchen, it doesn't add more heat than you pay for.

On the other hand, I suppose that if you put the entire fridge outside, with only the coils inside the house, in some way, you'd gain small amount of extra heat. I think a heat pump designed for the purpose of heating the house is probably a better bet. This type sort of "steals" heat out of the cool outside air, and moves it inside. It makes the outside air colder in order to heat the inside of the house.

By the way, for those of you who may be considering a heat pump to heat your home, I'd sure recommend investigating a geothermal (ground source) unit. Way efficient.


-- jumpoff joe (, May 08, 2001.

I didn't express that very well did I Joe! I meant that the heat released into the kitchen would come from the electricity consumed plus the heat taken from the water or whatever is in the fridge.

-- john hill (, May 09, 2001.

You might even think about building your own super insulated box and adding the compressor to the top. (Backwoods solar electric carries an efficient compressor and coils, not cheap but better than Sunfrost.) You could then build your fridge to suit yourself with the best insulation you can find. With the compressor on the top, it wouldn't be heating the box the way all modern fridges do. If anyone has one of those old refers with the coil on top and wants to get rid of it.....


-- Rick Hostetler (, May 15, 2001.

-- (, July 13, 2001

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