Refrigerator Insulation

jjackstone · 03-26-09, 12:00 AM

Here is a project I have been considering for a couple years. The fridge in the house is an older frost free version that is pretty much an energy pig. My roommate owns the house and is not able to replace it at this time so that isn't a good option. It normally consumes between 3 and 3.5Kwh/day. I have had a Kill A Watt on it for a couple years. While inspecting new fridges I noticed that most of the Energy star rated ones had at least two inches of insulation. The one at the house only has about an inch. A few days ago I put some 2 inch Foamular 150(pink foam) on the top and sides of the refrigerator to see if it would make a difference in energy usage.

For the four days previous to that, we were using 3.16Kwh/day.
For the last three days, the usage is down to 2.6Kwh/day.

That's a 17% decrease. The ambients have been pretty steady for the past week so no big differences there. We are not using the refrigerator any differently than normal.

Total cost of this project +$21.00.

Our electricity rates including taxes average about 15 cents/Kwh. So a savings of .56Kwh/day has a payback time of about 250 days. Cheaper than buying a new fridge at the moment.

If anyone else should decide to try this, just be aware that the condensor coils for the fridge are often somewhere in the walls rather than the rear. All I did was feel for hot spots. I never really felt any hot spots on the sides or top but the front dividing wall gets warm while the compressor runs. One reason I didn't cover the front also.

Probably won't run this experiment too long as my roomie is more concerned with aesthetics than I am(and it's her house). However, as I thought about that issue, I think a quick 3M spray on adhesive and some nice cloth could improve the looks inexpensively.

I have a few pix attached.

Enjoy,
JJ

SVOboy · 03-26-09, 01:28 AM

That's pretty good for just that much. I wonder if you would be able to pick up a free fridge that is a bit more efficient. How old is that one?

Daox · 03-26-09, 07:57 AM

Very nice! I can't say this thought hasn't passed through my head too haha. You're right, its not pretty, but it definitely works. Perhaps I'll do something similar with my chest freezer downstairs. Good stuff JJ!

Higgy · 03-26-09, 10:38 AM

Huh...I wonder if that would help a freezer or fridge even if it's already energy efficient?

Daox · 03-26-09, 12:08 PM

The biggest reason its probably energy efficient to being with is because it has more insulation. Just like a superinsulated house, a superinsulated refrigeration unit is going to hold its heat/cold better.

jjackstone · 03-26-09, 02:06 PM

It would probably help most refrigerators. Just need enough space. The other factor is always the law of diminishing returns. For me it only cost $21 for a 16% gain. If it cost $50 or a hundred, I might not have done this.
JJ

Higgy · 03-26-09, 03:26 PM

Ya, it's about 22 bucks for a 2"x24"x96" board up here.

I wonder if double sided tape would work to keep it in place. Then some kind of glue to hold the two pieces on the side with the top piece.

For asthetics, why don't you just make the cuts along the edges a bit sharper. Then pull the two side pieces up to the top part of the top piece...so it looks like one big square instead of the L shape on both top corners. Don't know if I'm explaining it right. I mean glue the two side pieces to the top pieces so it looks like one big upside down U if you took it off. Then just stick it to the sides of the fridge somehow then paint it white. A nice glossy white would make it look like part of the fridge. Although I don't know how well foam can be painted. I'm guessing it may just suck that paint right into it. I dunno...just a thought.

Good job though. I'm thinking of doing this to my fridge downstairs now. Gonna put the killawatt on it and see what kind of energy it drains. If it works well on the fridge, then I'll put it on the freezer too.

Ryland · 03-26-09, 05:25 PM

you should check the back, it might be old enough that it has the coils back there instead of under the skin, if that is the case then add some reflective insulation between the fridge and the coils, also check the door seals, new seals are pretty cheap, $35 or so.
also, if the fridge is not already full, adding some jugs of water to it will give it mass to keep that cool in, stead of letting all it escape with the air when you open the door.

truckncycle · 03-27-09, 06:45 PM

Quote:

Originally Posted by Higgy

Then just stick it to the sides of the fridge somehow then paint it white. A nice glossy white would make it look like part of the fridge. Although I don't know how well foam can be painted.

If you paint it, don't use spray paint - it melts the foam.

jjackstone · 03-26-09, 07:21 PM

Higgy,
Pertaining to more permanently mounting the foam I had considered using the inexpensive rolls of plastic(?) type magnets. They are pretty cheap. Then just make a couple slight grooves in the foam and RTV the magnets to it. As light as the foam is, the magnets wouldn't need to be terribly strong.
I understand what you are saying about the top side. The reason it ended up looking as it does is because that was one full 4x8 sheet cut in various sizes to fit the fridge. Didn't want to burn another $20 for a few more inches of foam.

Ryland,
Coils are not in the back on this model. Seals appear to be okay. If I put a bright flashlight in the fridge and turn off the lights at night I can't see any light shining through. I think mostly the high usage is because of the auto defrost cycle. I have considered bypassing the timer but I don't believe my roomie would let me get by with that mod.
We're usually pretty full but the water jug is a good idea.
JJ

03-26-09, 12:00 AM	#1
jjackstone Helper EcoRenovator Join Date: Mar 2009 Location: Sacramento,Ca Posts: 88 Thanks: 5 Thanked 32 Times in 23 Posts	Refrigerator Insulation Here is a project I have been considering for a couple years. The fridge in the house is an older frost free version that is pretty much an energy pig. My roommate owns the house and is not able to replace it at this time so that isn't a good option. It normally consumes between 3 and 3.5Kwh/day. I have had a Kill A Watt on it for a couple years. While inspecting new fridges I noticed that most of the Energy star rated ones had at least two inches of insulation. The one at the house only has about an inch. A few days ago I put some 2 inch Foamular 150(pink foam) on the top and sides of the refrigerator to see if it would make a difference in energy usage. For the four days previous to that, we were using 3.16Kwh/day. For the last three days, the usage is down to 2.6Kwh/day. That's a 17% decrease. The ambients have been pretty steady for the past week so no big differences there. We are not using the refrigerator any differently than normal. Total cost of this project +$21.00. Our electricity rates including taxes average about 15 cents/Kwh. So a savings of .56Kwh/day has a payback time of about 250 days. Cheaper than buying a new fridge at the moment. If anyone else should decide to try this, just be aware that the condensor coils for the fridge are often somewhere in the walls rather than the rear. All I did was feel for hot spots. I never really felt any hot spots on the sides or top but the front dividing wall gets warm while the compressor runs. One reason I didn't cover the front also. Probably won't run this experiment too long as my roomie is more concerned with aesthetics than I am(and it's her house). However, as I thought about that issue, I think a quick 3M spray on adhesive and some nice cloth could improve the looks inexpensively. I have a few pix attached. Enjoy, JJ Attached Thumbnails

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03-26-09, 01:28 AM	#2
SVOboy Administrator Join Date: Aug 2008 Posts: 291 Thanks: 3 Thanked 4 Times in 4 Posts	That's pretty good for just that much. I wonder if you would be able to pick up a free fridge that is a bit more efficient. How old is that one?

03-26-09, 07:57 AM	#3
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Very nice! I can't say this thought hasn't passed through my head too haha. You're right, its not pretty, but it definitely works. Perhaps I'll do something similar with my chest freezer downstairs. Good stuff JJ!

03-26-09, 10:38 AM	#4
Higgy The Gardener Join Date: Oct 2008 Location: Manitoba - Canada Posts: 492 Thanks: 17 Thanked 8 Times in 7 Posts	Huh...I wonder if that would help a freezer or fridge even if it's already energy efficient?

03-26-09, 12:08 PM	#5
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	The biggest reason its probably energy efficient to being with is because it has more insulation. Just like a superinsulated house, a superinsulated refrigeration unit is going to hold its heat/cold better.

03-26-09, 02:06 PM	#6
jjackstone Helper EcoRenovator Join Date: Mar 2009 Location: Sacramento,Ca Posts: 88 Thanks: 5 Thanked 32 Times in 23 Posts	It would probably help most refrigerators. Just need enough space. The other factor is always the law of diminishing returns. For me it only cost $21 for a 16% gain. If it cost $50 or a hundred, I might not have done this. JJ

03-26-09, 03:26 PM	#7
Higgy The Gardener Join Date: Oct 2008 Location: Manitoba - Canada Posts: 492 Thanks: 17 Thanked 8 Times in 7 Posts	Ya, it's about 22 bucks for a 2"x24"x96" board up here. I wonder if double sided tape would work to keep it in place. Then some kind of glue to hold the two pieces on the side with the top piece. For asthetics, why don't you just make the cuts along the edges a bit sharper. Then pull the two side pieces up to the top part of the top piece...so it looks like one big square instead of the L shape on both top corners. Don't know if I'm explaining it right. I mean glue the two side pieces to the top pieces so it looks like one big upside down U if you took it off. Then just stick it to the sides of the fridge somehow then paint it white. A nice glossy white would make it look like part of the fridge. Although I don't know how well foam can be painted. I'm guessing it may just suck that paint right into it. I dunno...just a thought. Good job though. I'm thinking of doing this to my fridge downstairs now. Gonna put the killawatt on it and see what kind of energy it drains. If it works well on the fridge, then I'll put it on the freezer too.

03-26-09, 05:25 PM	#8
Ryland Master EcoRenovator Join Date: Mar 2009 Location: Western Wisconsin. Posts: 913 Thanks: 127 Thanked 82 Times in 71 Posts	you should check the back, it might be old enough that it has the coils back there instead of under the skin, if that is the case then add some reflective insulation between the fridge and the coils, also check the door seals, new seals are pretty cheap, $35 or so. also, if the fridge is not already full, adding some jugs of water to it will give it mass to keep that cool in, stead of letting all it escape with the air when you open the door.

03-26-09, 07:21 PM	#10
jjackstone Helper EcoRenovator Join Date: Mar 2009 Location: Sacramento,Ca Posts: 88 Thanks: 5 Thanked 32 Times in 23 Posts	Higgy, Pertaining to more permanently mounting the foam I had considered using the inexpensive rolls of plastic(?) type magnets. They are pretty cheap. Then just make a couple slight grooves in the foam and RTV the magnets to it. As light as the foam is, the magnets wouldn't need to be terribly strong. I understand what you are saying about the top side. The reason it ended up looking as it does is because that was one full 4x8 sheet cut in various sizes to fit the fridge. Didn't want to burn another $20 for a few more inches of foam. Ryland, Coils are not in the back on this model. Seals appear to be okay. If I put a bright flashlight in the fridge and turn off the lights at night I can't see any light shining through. I think mostly the high usage is because of the auto defrost cycle. I have considered bypassing the timer but I don't believe my roomie would let me get by with that mod. We're usually pretty full but the water jug is a good idea. JJ