Another thought on the heating issue. It seems when it's cold outside people turn the heating up higher (and when it's really hot outside they turn the air conditioning cooler), but what that does is increases the thermal difference between inside and outside, which increases the "thermal shock" of going from one to the other. I figure the best thing to do is to keep the place as cool as you can while staying comfortable in the winter, and as warm as you can while staying comfortable in the summer.
As I mentioned above that keeps your bills down because the heater or a/c is doing less work, it means you don't go from a cold house to gasp-inducing heat in the summer, or cold outside to hideously warm and dry indoors in the winter, in the winter it also avoids stripping all the humidity out of the air, and does all that while saving you money.
Winter can be a problem because hot air can hold a lot more moisture than cold air, so if you heat air without adding moisture you reduce the relative humidity. Years ago I bought a device called an air washer that essentially had a load of rotating ridged disks that carried lots of tiny pockets of water from a reservoir, then as the disks rotated the water poured out and ran back into the reservoir. A fan blew down from above onto the disks. The whole thing washed dust and pollution out of the air, and because there was air blowing over moving water it also evaporated water to increase the relative humidity, but without boiling it as so many cheaper humidifiers will do. You have to refill the reservoir every day or two (more or less depending on how hot and dry it is), and every once in a while you have to clean the base to get all the accumulated dust and corruption out of it. It wasn't cheap but it was worth every penny.
