We are about finished with our rec room and one of the things hubby did was to install another ductless mini-split heat pump. I hope I don't bore you with this but these things are really high tech. He wanted to heat and cool the whole house with these but I only let him do the upstairs and the rec room. I just wasn't sure that they would work. Of course, he has proven me wrong. They work great and are ideal for heating and cooling individual rooms especially if you have no where to run ductwork. This is why they worked great upstairs since we have a vaulted ceiling and no attic space.
This is how they work: they are just like central heating and cooling units but they don't have any duct work. The inside unit hangs high on one of the walls and has two copper tubes and a few wires running through the wall to an outside unit. Instead of a thermostat, you use a remote control that hangs on the wall or can sit anywhere in the room. The outside unit works just like a regular outside unit only much smaller and quieter. Some of the manufacturers make units so you can heat and cool up to four rooms individually off the same outside unit. Our upstairs rooms each have an inside unit that hooks up to one outside unit. This one runs off of 220 volts but the new one hubby put in the rec room runs off of 110 volts just like a lamp. We now have 2400 square feet and our highest electric bill was $215.00 in July and we kept the whole house at 72 degrees.
These units have been used for years in Asia and the Caribbean but are fairly new in the U.S. Recently, I saw an ad on TV during This Old House. Most people that come in the house never notice them. These would be great for old houses or a room addition. Ductless mini splits promise to make old window units obsolete. Efficient, quiet, hot and cold air - perfect.