[sionnsar]

Thanks! When I was beginning my energy-efficiency studies a while back I noted a remark somewhere or another that the most effective barrier against unwanted solar heating begins *outside* the building envelope. Obvious? Yes. But oft forgotten.

I'd like to have A/C here for more comfort but can't justify the expense for the few days we need it, though the furnace/air handler we put in a long time ago will accept an A/C addition.

The Scot in me prefers low-cost solutions.

[Monkey Face]

Some folks in the Intermountain West use “heat pumps.” I don’t know much about them, but it may be what you’re looking for. Heat in the winter, cool in the summer and the rest of the year is “comfortable.”

[NicknamedBob]

" I'd like to have A/C here for more comfort but can't justify the expense for the few days we need it, though the furnace/air handler we put in a long time ago will accept an A/C addition. The Scot in me prefers low-cost solutions."

Sounds like you could use a "ground loop". These vary in configuration, from a trenched-in buried plastic pipeline to a vertical bore with drop-in plastic loop, backfilled with the same dirt you dug out.

If you have access to a pond, you can put the loop in the bottom of the pond.

The basic idea is to circulate water or other fluid to pick up heat or drop it off, and then use a copper coil or such inside the house with a regular box fan on it.

The coolness of the ground will be transferred to the house, and when you no longer need it just turn off the circulating pump and the fan. Or put it on a thermostat.