Adding Extra Insulation to a Cooler/Refrigerator
WHY I NEED REFRIGERATION
- I like cold drinks! For that alone it’s worth it to me to have a refrigerator.
- In the city you are always surrounded by grocery stores so you can buy in very small portions, but that will cost you more than buying in larger sizes.
- I love Miracle Whip and don’t like mayonnaise, so I buy it in 32 oz. jars and it needs refrigeration. And yes, that alone is enough reason to have a cooler.
- I want to have fresh vegetables for salads and frozen fruits for smoothies. That requires refrigeration.
- If you are a boondocker and living far away from cities, driving into town frequently to buy fresh meat, fruits and vegetables would be much too expensive in gas. The larger your fridge the longer you can sit and not burn gas driving into town for supplies.
- I can’t afford to eat out all the time so I cook for myself. I prefer to cook a larger portion and then save it as leftovers to eat later. There are three reasons why leftovers work so well for me:
- Cooking one large meal allows me to buy food in larger packs which saves money.
- By cooking a large meal and then saving the left-overs, I reduce my cooking time and dishwashing. For example if I cook 4 hamburgers at once, I only have to wash the skillet once saving me time and effort.
- Many meals taste better the second day!
When I started living in a van in 1995 I had no idea there was such a thing as a 12 volt compressor cooler (and solar was much too expensive then so even if I knew about it I couldn’t have one anyway). So I bought an Igloo 5-Day cooler and started buying bags of ice. Because I lived in a box van with very little ventilation, it got really hot in the summer which meant the ice melted fast. Right away I knew I needed to add more insulation! I had heavily insulated my box van with 2-inch-thick sheets of Styrofoam so I had some left over. There was no use letting it go to waste so I cut it into the right size and covered the cooler with it. After they were cut I used Gorilla Glue to glue it permanently to the sides and bottom of the cooler. Gorilla Glue 50004 Adhesive, 4-Ounces
The top was harder because the lid had to swing open. I had some closed cell foam sleeping pads on hand so I cut them to fit and glued them to the top instead. I also placed one under the cooler for extra insulation. I had used those in my backpacking days and knew they were an excellent insulator! I’d slept on them at -30 below zero on top of snow and they kept me warm and the cold out of my sleeping bag. Remarkably, the snow never melted underneath me. I had found a whole bunch of them as surplus that had been issued by the U.S. Army to their cold-weather troops. They only cost $5 each so I bought enough to cover the entire floor of my box van as insulation and then threw carpet over it. When I sold the van, I kept several of them and I still have a few left today. Amazon.com is now selling the exact same pad, but they are a lot more than my $5 surplus ones! GI Closed Cell Foam Sleeping Pad
USE BLANKETS AND PILLOWS ON THE LID
I could feel the top getting cold and so I was fairly sure I was still losing cold through it. So I took an old blanket and folded it up to fit and draped it over the top and then put a pillow on top of it. That seemed to help.
WITH AN ICE CHEST, USE A KITTY LITTER TUB TO HOLD THE ICE
Finally, there was one other thing I did to the cooler that helped it to stay cold and made using it much more pleasant, and that was using a kitty litter tub to hold the ice instead of just dumping it in the cooler. Cold transfers very easily through water and plastic so as the ice melted and the cooler filled with water its cold went straight out. By putting it in the Kitty Litter tub the water stayed inside it and never directly touched the walls. Instead it was surrounded by air which is a far superior insulator. As a bonus, my food was no longer swimming in ice water and that saved me a fortune in foo not thrown away!
Adding extra insulation made a big difference in how long it stayed cold when it was hot. There’s no doubt in my mind it was well worth the little bit of money and effort it cost me to insulate it. I used that cooler for 7 ½ years and the glue and the Styrofoam held up well. I highly recommend it as well as putting the ice in a kitty litter bucket.
In 2009 when I bought my Dometic 25 quart 12 volt compressor fridge, I was not inpressed with how thick it’s walls and lid were so there was no doubt that would add extra insulation to it as well. At that time I only had 55 watts of solar and I was not at all confident that would be enough, so in order to make it run as little as possible I wanted it to be super-insulated. So I did exactly what I had done to the ice chest. The result was that the compressor only came on 3-5 hours a day. Even so, it was a constant struggle with having enough power so six months later I added a second 135 watt panel and that solved all my power problems. Unless it is cloudy, I always have all the power I need.
As you know, I just recently bought a new Whytner 65 quart refrigerator. While I am very impressed with the thickness of its wall, and how little it runs to stay cool, there was still no doubt I would extra insulation. This is one of those few cases were more is better! Because I didn’t have 100% confidence in the compressor in it, I thought if adding extra insulation reduced the amount of time it ran, it would be just that much longer before I had problems with it. In other words, if the compressor ran half the time, it would last twice as many years.
USE POLYISO INSULATION!
I did one thing differently this time, instead of using standard white, pink or blue Styrofoam I used a different type of foam board called Polyiso. I had only recently learned about it and researched it and there is no doubt I will only be recommending it from now on. A 4×8 sheet of it costs $20 at Home Depot and it has an R-Value of 6.2 per inch, the highest of all foam boards (for comparisons sake, the R-Value of pink spun fiberglass batt insulation is only R 4 per inch). It comes with a very heavy aluminum foil reflective barrier on both surfaces and was much easier to cut than standard white Styrofoam because it doesn’t have all the little white balls that break off with every cut; I hate the mess they leave! Polyiso is very highly recommended! More info here: http://www.greenzone.com/general.php?section_url=14
For the first time I took pictures of how I insulated it, so here they are. I hope they give you some ideas of what you can do with your own cooler whether it uses ice or is 12 volt.