Derek Broughton wrote:

...My barn fridge gets unplugged from October through March, with
an EH38 "Easy Heat" socket ($10.99 at Lowe's) in series with a 100 W
trouble light in a bottom drawer to keep the carrots and apples from
freezing.

Unlike water, they don't actually freeze at 32 F...

What's the actual power draw on an Easy Heat socket (whatever that is) in
series with a 100W bulb?

The socket is a thermostat that turns on the 100 W bulb when the air
near it is less than 38 F, so it uses 0 W when off and 100 W when on.
I've never measured the energy usage.

It sounds like at best a zero-sum game - a quick look at Canadian Energuide
ratings shows small refrigerators to be using less than 1.5 kWh daily, so
your heating appliance needs to be using less than 50W.

....1.5kWh/24h = 62.5 W, but it probably uses less, on a continuous basis.
The fridge might have 80 ft^2/R10 = 8 Btu/h-F of conductance. January
is the coldest month in Phila, averaging 30.4 F. The unheated barn tends
to average daily temp swings. The trouble light is in a drawer with a few
1 liter water bottles under some fiberglass insulation, so it keeps the
fridge just above freezing. In January, it might supply 24h(32-30.4)8
= 307 Btu/day, using 307/3412 = 0.09 kWh, ie 3.75 W on a continuous basis,
ie 17X less than a fridge in a warm room. It seldom comes on in February
(average 33.0) or March (average 42.4.)

With some rewiring, the fridge might use its own light near the top of
the box for heat, with the fan running without the compressor whenever
the light is on to distribute warmer air near the lower part of the box.

Nick