You need to ventilate the cupboard or larder...
---- one in the front bottom of the dooor (intake)
---- one in the front top of the door (exhaust, by convection)
o Door left 2" ajar
---- you will find the cupboard slightly warmer when you walk in
---- however hot air will exit, drawing in cooler air near the floor
Cooling appliances work by...
o Compressor uses gas-liquid phase change to pump heat out of a box
---- compressor does not run continually (it would soon fail)
---- compressor cycles on & off based on an internal thermostat
o Appliance sits in its own ambient temperature
---- appliance in a cupboard will heat ambient quite considerably
---- so the compressor will cycle more often & use more power
In a cupboard you may want to set the appliance so it tilts backwards.
o So the door naturally swings closed if someone doesn't shut it properly
o This is particularly important for freezers where food can go off fast
No it does not "double insulate" the fridge...
o Fridge is a heat pump removing heat from inside the fridge
---- insulation stops the heat from outside the fridge getting in quickly
o Higher temperatures outside the fridge
---- reduce effectiveness of the insulation (higher temp delta)
---- reduce effectiveness of the fridge coils to dump heat (lower temp
---- increase the amount of energy the fridge will use
Modern fridges/freezers do seem to dissipate a lot less heat than some
of 20yrs ago - which results in lower thermal input into the surroundings.
However the same applies, and energy does add up over a long time.
Personally I would simply not shut the cupboard door, stick a fridge
thermostat inside and glance at it every time you open the fridge.