In article ,
Richard Downing writes:
It's b....locks. The physics is easy. A freezer is a heat pump, it
pumps heat from the inside to the outside. The cooler the outside is
the less energy is required to attain the correct temperature inside.

The engineering is not so easy though. Units are somewhat
constrained on temperature range they can cover, so they
are designed to cover the most common temperature range in
a home, i.e. 16-35C.

Other considerations: The running temperature of the pump - better in a
lower temperature as long as any grease used in the bearings doesn't
freeze (no liquid nitrogen in your utility is there?).

Pumps usually outlast a freezer at normal ambient temperatures,
so there's not much to be gained trying to make one last longer.

The working fluid (Ammonia usually) doesn't freeze, or fail to
evaporate. (Only a problem in the Outer Planets, and certainly not your
utility room)

Ammonia hasn't been used in domestic fridges or freezers for over
50 years (except adsorption fridges). It is still used in some
very large industrial fridges and freezers.

--
Andrew Gabriel