Are you losing your cool??
Or, more accurately, is your refrigerator losing its cool? That is, is the cold air that you’ve spent so many amp-hours to create just slowly creeping away through poor insulation on your refrigerator?
I got so many great tips and ideas from cruisers at the “Improve Refrigerator Efficiency” presentation at LoretoFest 2013. Thanks to all of them for both questions that inspired discussions and comments of how they dealt with various things.
One of the questions that came up in a couple of different contexts was how to tell if your refrigerator is poorly insulated and how to figure out if it’s just on one side or all over. The same tests work if you have an ice box or even a cooler.
The quick test for insulation is actually quite simple and, better yet, free. Put your hand on the counter where the refrigerator isn’t (and also not an area in the sun or where something hot or cold has just been sitting), then put it on the counter over and around the refrigerator. If it feels colder, the refrigerator isn’t insulated as well as it could be and cold is seeping out. If it feels colder in some areas than others, you may have voids.
A more sophisticated test is to use a laser temperature gun. Actually, the little laser light simply shows where you’re aiming and the temperature is sensed through an infrared sensor. Five years ago, these were fairly expensive and few cruisers had them. Now, you can buy them for less than $25 and they are also useful when dealing with diesel problems. Amazon carries several less expensive models (click here for their best selling one); many auto parts stores carry them but they usually have more “bells and whistles” and cost quite a bit more.
First check the temp on a nearby cabinet as a baseline. Then aim the gun along the top and sides of the refrigerator box and look for cool areas. If a whole side is cool, there’s insufficient insulation in general on that side. If you get temps that vary by more than a couple of degrees for no apparent reason in the middle of a side, it’s likely a void.
Don’t forget to check around doors and lids — they are frequently not well insulated and you may also find leaking seals. Read more about checking seals.
For tips on improving your refrigerator insulation without rebuilding the entire box (yes, doing the whole box is the best solution if it’s done right but it’s also expensive and time-consuming . . . and you won’t want to be living aboard while doing it), read Refrigeration: Extra Insulation.
Simplify meal prep on board with proven strategies for provisioning, maximizing fridge space, and cooking delicious meals aboard your boat.

Carolyn Shearlock has lived aboard full-time for 17 years, splitting her time between a Tayana 37 monohull and a Gemini 105 catamaran. She’s cruised over 14,000 miles, from Pacific Mexico and Central America to Florida and the Bahamas, gaining firsthand experience with the joys and challenges of life on the water.
Through The Boat Galley, Carolyn has helped thousands of people explore, prepare for, and enjoy life afloat. She shares her expertise as an instructor at Cruisers University, in leading boating publications, and through her bestselling book, The Boat Galley Cookbook. She is passionate about helping others embark on their liveaboard journey—making life on the water simpler, safer, and more enjoyable.
Rita Atkinson says
Thanks for this, we are just building one in our boat and this is good information
Sarah says
How are the temperature guns helpful with diesel problems?
Carolyn Shearlock says
Many times you want to know if a particular area is running hot — or cooler than normal. The temperature gun is about the only way to get good info on specific areas, such as the exhaust pipe, heat exchanger, oil cooler, etc.
Frank Collins says
I try in tighter exterior places such as against the hull and cooler and refrigerator to use a can of the expanding foam insulation . Wear old gloves as this stuff is quite sticky however if you have a tight area it will expand and insulate in areas of the exterior of your box.