Hi everyone.
 

Joined up because I'm interested in heat pumps. Currently building my own tiny 500 sq ft house and want to keep my bills low.

500 square foot should only need 6,000 BTU per for cooling if it's well insulated.

Only R13 in the walls with 1/2" sheathing and 5/8 wood siding. 2' overhangs helps with the sun, only the back wall heats up in the afternoon but I'm adding a wash room and porch back there that will help that. R30 in the ceiling keeps the attic heat up there where it belongs. 12kbtu a/c in the wall has no problems at all keeping it cool inside. Only two windows helps too.