My house has hot air heating - very much a 60s thing in the UK although I'm aware it's more common on other countries. I've been tempted to see if I could modify things to blow cooled air around the house when it's really hot, but have resisted so far.
Fred27 What you suggest is exactly how my air conditioner works. We have "central forced air" - one furnace and a bunch of ductwork. The air conditioner coils are mounted in the furnace outlet ductwork. The system uses the furnace fan to circulate the air. Our thermostat also allows us to just turn the fan on and circulate air. If you have a cellar, you could draw your intake air from there. You may not get good distribution of the air in the rooms the air is blowing into, but my basement is easily 10 degrees F cooler than upstairs. It could be worth a try. My temptation is the opposite - to get the warm ceiling air in the Winter and pipe it down into the basement.
