If anyone is considering some kind of heating or air conditioning unit to replace what you now have, I can wholeheartedly recommend the Mitsubishi air source heat exchanger. We have ceiling resistance heating which gobbles up tons of power in the winter and no air conditioning.
Out power provider was offering significant rebates to anyone who wanted to install one of these systems, so we had a guy come out to see what he could do. Ended up purchasing a mid-range unit that allows the connection of two indoor heads that control the temperature. The same head heats in the winter, and cools in the summer - it is almost absolutely silent both indoors and outside. It holds the set temperature to within a degree of the set point. It has been really hot here (nearing 100F), and the units hold the temperature perfectly, with no blower or any other kind of mechanical noise.