Save energy. If you follow my instructions you could switch off your fridge during the colder months. Make yourself a cold cupboard larder which can be cold enough for a few days between shopping trips to keep fresh most stuff like milk, bread, meat, fish ect.
I made mine by converting a very low down cupboard which is below the waterline outside. First of all have the cupboard with all it's internal walls completely separate from any other space, the back wall is the boats hull. I squashed flat loads old aluminium pie dishes which I saved for some time and stuck em all over the walls and ceiling if you like to call it that and the inside of the door, all stuck with dots of cheap silicon. It's bean wonderful, once or twice in mid winter I've gone a week between shops and nothing had gone off. Saved a bomb of gas that my fridge would have used, a similar saving would be had with an electric fridge 12v or mains.