I’ve written about this in parts before and will probably write more in the future, but I wanted to cover this now since it’s timely. RV refrigerators do not function well outside of comfortable camping temperatures — if it’s too hot or too cold, it will have trouble cooling, sometimes to the point of not cooling at all. We experienced this first-hand in our recent trip to Ketchum, ID with temperatures down to -10ºF and as high as 20ºF.

These are my observations, experiences, and learnings:

• An RV refrigerator will function normally until about 25°F after which the cooling performance will decline. Under normal conditions, the boiler converts the ammonia-water mixture into vapor, which rises up to the point where the water portion re-condenses leaving the ammonia vapor to continue on to the cooling section. When overly cold out, the ammonia condenses too early and prevents much, if any, of the ammonia vapor from reaching the cooling section.
• The “cold weather” package (installed standard on ORV units) adds a heat strip to help improve cold weather performance down to about 0°F. The 0°F rating is at zero wind speed, which means any wind chill at all should be factored in.
• When the cooling stack stops functioning, the fridge and freezer will slowly warm, functioning basically as a normal cooler would.
• The manufacturers (Norcold, Dometic, etc) recommend using propane mode below 32°F because the waste heat helps the cooling tower function better. Some also recommend the addition of a 25W incandescent bulb for its heat.
• The manufacturers do not recommend blocking off any of the lower vents near the boiler for liability reasons, but it’s a common remedy recommended in various online communities. The venting is sized for summer use, and winter use does not require nearly as much. Above freezing, and especially when sun hits the fridge side, the vents should be fully unobstructed.