[obeone]

There are 2 aspects to home comfort: Having the right amount of heat in your house, and keeping the temperature in your home from fluctuating. As others have pointed out on this thread, there are many ways to add and remove heat from your home. I would suggest that the second point, the thermal mass of your home, is an often overlooked item that is very easy to design in pre-construction, but very hard to add as an afterthought. Interior stone, concrete, and water (like a fountain, for example) efficiently and perpetually absorb and radiate the existing heat into an already conditioned space in a way that is eminently comfortable.