You might be able to use the thermal stability you have underground to help cool the house. Granted, this is more expensive, but probably far less costly in the long run. The basic idea is to bury a heat exchanger (coils of tubing) deep underground and circulate a fluid to move heat from hot to cold.
You can use this two ways: You can use it to try to cool the house directly by embedding tubing in the floor/walls or some other approach. Or, you could use it to improve the efficiency of an air conditioning unit by providing supplemental cooling of the A/C unit heat exchanger coils.
You can use this two ways: You can use it to try to cool the house directly by embedding tubing in the floor/walls or some other approach. Or, you could use it to improve the efficiency of an air conditioning unit by providing supplemental cooling of the A/C unit heat exchanger coils.