Save 50% power by insulating your fridge

I just wanna share a successful story: More than a year ago i insulated my fridge with styrofoam which resulted in a reduction of powerconsumption down to 50%. Till today it is running flawlessly. More details you will find here: http://coolfridge.blogspot.de/

Anyone who did try something similar?

Allen

I've never tried this or even heard of anyone doing it, but you did a great job. It looks awesome.

Thank you for your kind remark. If anybody is thinking of doing some insulation of his own fridge, you might be interested in some tips and thoughts about that: http://coolfridge.blogspot.de/2011/12/pimp-your-fridge.html

Please feel free to discuss things here or at my blog!

Have a nice day. Allen

my solution to out of site cost of running a refrigerator .. repurposed a chest freezer to be a dedicated fridge.. added a couple of baskets internally.. and installed a simple external thermostat (cost $65)

Bottom line cost to operate my fridge $1 a month.. it does not run more than 5 minutes per hour and less when I am not using it over night No problems with covering or worries about insulating parts of the fridge that might have coils on the external parts of the skin that radiate heat.. This is a real problem that if you dont know it is there.. you will burn up your compressor.. basically turning your fridge into a boat locker

Hi Steve, that is a nice solution you have done. I am still dreaming of something similar. I was thinking of a stand-up freezer preferably from Liebherr and to install a thermostat of a normal fridge inside. That way i would have a super efficient fridge. I calculated that it would consume maybe 30kWh a year which means 1/3 of that what the best fridge on the market takes. You took an external thermostat? Why not internal? Did you measure the temperature inside? Did you measure the powerconsumption per day?

You are right that there are some things to mind when you do your insulation yourself. One is that you mentioned: you need to know where the condensor is cause it needs to stay clear. I go a bit more into the details here: http://coolfridge.blogspot.de/2011/12/pimp-your-fridge.html

Greetings from Allen!

I suppose a couple of notes are needed here.. with a chest type freezer ... open the lid .. and the cold air stays in the bottom.. open an upright and all of the cold air sinks out onto the floor.. so you have lost an entire load of chilled air everytime you open your fridge.. This is large part is why any upright is be it a fridge or freezer by its very design will be 75% less efficient than a chest...

as to the thermostat .. it is an external control with a tube and bulb that I placed into the back of the chest.. so there is a tube of about 1/32 of an inch that passes under the gasket in the back of the chest. I could have drilled a hole and refoamed after I inserted the tube.. but thought this redundant. the thermostat powers off the main 110 volt line coming into the unit.. so the freezer is actually plugs into a switch that is set to line voltage..

Steve

I know the discussion about the chest type and upright type fridge or freezer. In my opinion the effect is largely overestimated, i never saw measured datas. You are talking about 75% less efficiency? Where did you take these numbers from? If you check the different models there is not much difference between that types, see here as an example Liebherr: http://www.liebherr.com/HG/de-DE/region-DE/products_hg.wfw/id-565538-0_37229-0 and http://www.liebherr.com/HG/de-DE/region-DE/products_hg.wfw/id-565536-0_28901-0. Of course the measurements of the producer dont involve door-openings. Opening the door maybe 10 times a day cant make much difference, especially if the freezer has closed drawers as you can see it at the pic of Liebherr-homepage cause here the air stays trapped in the drawer even if the door is open. In addition to that most of the cold is "stored" not in air (which is fast cooled down again) but in the walls of the fridge and in the food and drinks you have got in the fridge. The comfort of upright fridges justifies the minimal loss in efficiency in my opinion.

Now i understand how you dealt with the thermostat. Sounds good. How much the fridge does consume over 24 hours?

Allen

To have some joy I suggest an experiment for anybody here to prove or disprove the theory: Opening the door in upright fridges or freezers results in a relevant loss of efficiency.
The experiment will be done like that: room temperature where the fridge or freezer is standing should be permanently meausured to be sure that it is stable. 1. The power consumption of the fridge/freezer will be measured WITHOUT opening of the doors at all over at least 24 hours. This can be done maybe when nobody is home for a day or weekend. 2. The power consumption will be measured WITH opening the doors whenever you use your fridge over at least 24 hours. The number of openings should be counted with a line-list to make sure it is not unrealistically high. Each opening should be short as it is recommended (and not 1 hour long openings lol Idealistic would be to measure how long the door openings are but maybe that is a bit complicated.

It will be calculated how much the fridge / freezer did consume over 24 hours in both cases to see how much difference there might be.

Anybody who will do this experiment might post its results here to make us more knowledgable!

Thank you!

Allen

efficiency suggest you go to one of the appliance stores.. they post power use on those yellow tags. that is where I get my efficiency rating.. most of the upright refrigerators seem to post in between 30 -40 dollars annual power consumption.. I know from my own experience that my conversion runs about $1 a month or $12 annualized. How do I know? meter reading for the house. What got me to move over to this was I was living in an apartment with a crappy fridge.. that never shut off.. all other inputs being equal I discovered that my monthly bill dropped to this level .. I also have timed the actual running time per hour down to 5 minute cycle time acording to the energy tag this unit will draw 277kw at $0.105 per kw or about $30 annually. I do keep a couple of 2 ltr bottles of water in the unit so I know that I also moderate the cycling due to this heat sink .. this is how I get my 70 -75% efficiency

I suppose the best way to actually measure the power used is to get a power meter and plug it in.. put one on your own fridge.. and remember there are kids big and small who go stand in front of the fridge with the door open LOL dont forget to go barefoot so you can feel the cold air spilling out.. think you need to consider just how much heavier cold air is as it sinks.. and stays within the chest as opposed to an upright that has no way to keep the air from flowing due to gravity this happens every time you make a trip to the grocery too.. as the door stays open while you loader up..

Steve

Thanks for your answers Steve. The efficiency rate at the store is measured without opening the doors at all i guess. At least the european union is measuring it like that. That means if a freezer is better than another it is because it is better insulated and has more efficient compressor and so on. Door-openings dont count.
Do i get that right that you calculated to pay 12dollars annually for the power consumption of your fridge? Given the price of .105 dollar per kWh it would mean 114kWh per year which is slightly less than my fridge if one is presuming the same room temperature. These numbers dont tell us that chest fridge is better 75% bmore efficient than an upright fridge.

Definately air flows outside of an upright fridge when the door is opened. But like in flats: if you open all windows fully and wind is blowing through your flat and than you close all windows after 3 minutes the rooms will be fast warm again cause walls and furniture do keep most of the heat and air does only have little heat. I read once that in a flat air has less than 30% of the warmth but i cant find these numbers again.

As soon i get back my power meter from a friend i will do the experiment i did suggest further up on this page. With that experiment we can understand better how much door opening does do to an upright fridge. Since you got a chest fridge, maybe you do exactly the same experiment with it, so you see what impact it has on your chest fridge. You need a power meter though . Its worth buying one anyway, cause it helps you to understand which device takes how much energy in your household, which in turn helps you reducing your energy bill. We went down to 500kWh per year for the whole flat by some easy measurements in our flat (mark that heating and warm water comes from a gas driven heating for the whole house and is not counted in these 500kWh/year).

guess there is a difference with real world still I figure my results are darn good.. figuring that my energy to chill my food for the entire year is about equivalent to running a 100 watt light for a bit over an hour an a half each month.. Even with figuring the door closed on cycles.. or that the contents of the fridge maintain their temps air around them does need to be re chilled to keep the contents from absorbing heat from the surroundings.

I need to buy another kill a watt

Just an update: After two years my self-insulated fridge is running nicely at very low power consumption. Now the fridge is 20 years old but it can compete with a modern A+ fridge. Details you find at my blog: http://coolfridge.blogspot.de/

Did anybody try something similar in between?

Have a nice day. Allen.

Hi Alan, I was given an upright freezer about 2 months ago and my first thought was to increase the insulation on the outside of the machine to conserve energy. We have a fridge/freezer in our home but needed a back up machine for all those bargains that seem to crop up when your home freezer is full so you miss out. The freezer is in my now defunct workshop and raised off the floor on bricks to give good air flow around those parts that need it. I have already put insulation on the top and will do the sides as and when I find it, (I like skips/dumpsters), I am not too bothered what it ends up looking like as long as it does its job. I phoned the friend who gave me the freezer and told him what I was doing and he thinks I am mad, he said the freezer is already triple A rated but why settle for that, Dave

I think that fridge will function much better if you move it far, far away from your oven.

Allen back to your original fridge: did you insulate the back of the fridge too? How much air space should be allowed at the back and the sides?
Would it work even with a fairly modern fridge?

Hi Angelika, i did insulate the back of the fridge. But of course its tricky, cause at the back my fridge has the condenser where it wants to get rid off the heat. So i insulated the fridge underneath the condenser. To make sure that enough air is floating around the condenser i reinstalled it a bit further away from the fridge by using longer screws.

Cj Verde. Dont worry about the oven not far from the fridge. The sidewalls dont get even slightly warm when the oven is in use. The reason for that is that the sidewall is triple-walled an a fan blows the heat to the frontside and away.

David, how is your upright freezer doing? Did you measure the energy consumption??

Greetings to all! Allen

Angelika Maier wrote:Would it work even with a fairly modern fridge?

I think it would. You have to find out where the condenser and the evaporators are. I dont know much about that. You might have a look here: Make your fridge green

Now the fridge ist running 3 years since i did insulate it ! And still no worries, just working decently!

http://coolfridge.blogspot.de/


Greetings. Allen

4 years! My extrainsulation works fine, fridge saves money and CO2. I am happy. You should try it

This is simply a 'must do' DIY modification. I had set a blanket on top of my chest freezer and noticed how cold it was a few hours later one day a while back. I added 1.5" foam to the bottom and it helped the machine to kick on less frequently. Next I need to add insulation to the top. I just recently noticed how efficient newer small chest freezers can be and with some extra insulation I could rather easily run one with a small PV power system (~$500). This is excellent for reducing the cost of going with renewable energy.

I also saved a few drawers from old refrigerators and use them in in my refrigerator to help keep things organized (which avoids waste), to keep some cold air from spilling out when the door is opened, and also I can simply grab the drawer I need very quickly without leaving the door hanging open while searching.

Allen Bear wrote:I just wanna share a successful story: More than a year ago i insulated my fridge with styrofoam which resulted in a reduction of powerconsumption down to 50%. Till today it is running flawlessly. More details you will find here: http://coolfridge.blogspot.de/
Anyone who did try something similar?
Allen

YES! We’ve been doing something like that for many years., since learning how entrenched commercial fridge makers were not intending to add much insulation to their boxes anytime in the foreseeable future.  
1st box was a dinosaur about 30 to 40 years old. We plugged it to a mechanical timer to shut it off for a few hours each night.
Then I used packing tape to attach 2” thick, R-10 rated foam panels, but only to the sides, top & front exterior, where there were no cooling coils under the skin.
That combo successfully saved about $20 per month off the electric bill, even on a later installed brand new, much smaller “energy star” rated GE fridge.
And, when there was a 3-day outage, right at the start, I taped the doors shut to prevent cool loss. That all saved ALL the food in it, except for a half-head of lettuce. All the frozen foods still had some ice, therefore, could safely be refrozen.
We repeated those modifications on 2 other subsequent fridges, equally successful.
Then got rid of the upright fridge & got 2 chest freezers (those already have more insulation...get ones with thickest insulation!). We plug each of those into separate mechanical (not digital) timers on a power strip.
The freezer box is on for 12 hours per day, off at night. The fridge-use box, the timer pins are set to be on 5 times in 24 hours, for 1-pin time slot, equally spaced around the clock is what works here—mileage may vary per your conditions...learning-curve!
The power strip can plug to a grid socket, or can plug to a battery box. We plug ours to a Goal Zero Li1400 box.  
Each cold box draws about 100 watts when on.
The timers limit on-time & work well with the battery box, while the thicker insulation of the chests holds the cold very well, in between run-times.
The Goal Zero boxes only recharge at about 60 watts plugged into grid power, but much more, if recharged from wind or solar.  
Right now, we mostly recharge from grid, but do have a few 30 watt panels inputting also....but even that has saved our food during times the kitchen circuits crashed for 2 days, because even the 60 watts corded from a working circuit was enough to buy enough time for repair to get done.  
This arrangement also saved the food during a 12 hour outage.  
And, using power from battery box with a pure sine wave inverter, protects electronics from brownouts & flickers too.
The only drawbacks to “outsulating” (or insulating the interior) of a fridge, is that ambient humidity can cause mold between the foam panels & box edges..easily cleanable or preventable by using MoldZyme enzyme spray (food-safe non-toxic enzymes that utterly stop mold).  And, outsulating a big cold box, takes up more room.
Converting to chest freezers takes up more room, too; and, used as a fridge, those will condense water inside, which needs drained...& treated with MoldZyme to prevent mold growth in case of temps being poorly adjusted...it’s a learning curve!
BUT!!
....SOME fridge makers are putting cooling coils under the skin of the box sides & top, now...and doing that in small units, too....just like chest freezers have.
That means you cannot “outsulate” those, but only insulate interior...reducing interior storage in already small boxes, is another kind of cost/benefit hazard.
Until fridge makers start doubling, or better, the insulation in their boxes, efficiency, including “energy star” is an utter sham.
Most full size & dorm fridges draw something like 500 to 700+ watts when running. And, are estimated to last about 10 years (if you’re lucky). That is awfully inefficient! And they pull other tricks to bypass the mandates.
Consumers must resort to creative problem solving, to do better!