Our heating and cooling is handled with the new stars on the efficiency stage, mini-split (or ductless) heat pumps. This is a rapidly expanding field that bears little resemblance to the heat pumps of the 1970's and '80's. Heat pumps exchange heat similarly to the way air conditioners or refrigerators do, but can work in both directions to provide both heating and cooling. The early units got a bad rap in the 80's for being inefficient at supplying heat below 30F or so, but the new Mitsubishi units we're using supply their full nominal heating output at 5F and continue to operate efficiently down to -13F. With a SEER rating of 26 and heating Coefficient of Performance over 3, the ductless heat pump is a terrific unit. But they gain even more efficiency from the fact that they can modulate down to run at partial load--so they will run on a very low setting if you just need a little heating or cooling, which is way more efficient than coming on, blowing hard, and shutting off. Another benefit in cooling mode is that the unit can dehumidify continuously, even at low levels of output. Aside from being a more comfortable way to get your space conditioning, it is also nearly silent. You literally can't hear these units unless you get your ear right up on top of them.
They have an outdoor unit that looks like a small, upright A/C condenser, and a wall unit with a fan that provides conditioning. Here's the rough installation of the units:
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| Master Bedroom |
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| Living Room |
