Freezers don't like being cold! Check your garage freezers from time to time. In fact, manufacturers explicitly tell us not to run freezers in unheated garages. But sometimes, we do

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I have three normal domestic freezers in my garage and I just noticed that the one that is a combined fridge freezer, was not in the right temperature range. It had warmed up to about -10C, which led to a loaf of bread starting to defrost. Fortunately all the meat in there was still rock solid, but still needs eating ASAP.
It reminded me that this problem happened on previous very cold winters, especially when the garage is under a layer of snow.
Many, if not most domestic freezers cannot work properly in cold temperatures of below about 16C.
So far, it's only the combined fridge freezer that has exhibited this problem. The free standing chest freezer has iced up on the outside and a newer under-worktop freezer is coping OK.
Absurdly, the solution in my case is to run an electric room heater to warm the garage up to a more comfortable room temperature.
I also offloaded much of what was in it to the other freezers and will try to use it up ASAP.
Definitely use Freezer thermometers.