the most valuable thing you can do with a square foot of winter ground
is store the coolth. Put out soda bottles full of water. Store them in
a heavily insulated toolshed. Like the old-timey ice houses. Fiberglass
batt isn't all that expensive. put aluminum foil on the shed to reflect
sunlight away, gains less heat.

Ice is incredibly good storage of coolth because it freezes at a very
low (relative to room temp) temperature, and because the heat-of-fusion
of water is so darn big. But if you don't have freezes, you don't have
freezes. Store the cold water anyway.

Air Conditioners chew up VERY large amount of electricity. Each BTU of
cooling power, that you can seasonally harvest instead of
machine-produce, is money in your pocket.