Mini-split what? It may be a mouthful, but these types of heat pumps have been used in Europe and Asia for years and are just now becoming more common in the U.S. They require no ducting and some models can even be integrated into a piece of artwork. Learn more after the jump!
You might be familiar with air-source heat pumps, which move heat from the cool outdoors into your warm house during the winter and then move heat from your cool house into the warm outdoors during the summer. Often times, the pump looks like an outdoor A/C unit and is connected to a home's ductwork. Mini-split heat pumps use the same technology but are often ductless, so they're a great solution for retrofits, additions or for homes that don't have a forced air system already in place.
Here's how they work: a small compressor unit sits outside and is connected to an inside air handler via a small conduit that houses the power and refrigerant. The inside unit is small and resembles a baseboard heater (though they're typically designed to be placed high on a wall). Without ducts to travel through, warm or cool air doesn't have a chance to leak out (which can account for 30% of energy consumption in a traditional forced air system!). Plus, because they move heat rather than generate heat, heat pumps can provide up to 4 times the amount of energy they consume, making for an extra efficient system. Furthermore, mini-split heat pumps can be purchased for a single room or zone or multiple air-handling units can be connected to a single outdoor unit for a multi-zone system.
The only downside? Many of the available models aren't very pretty and tend to be an unwanted focal point in a room (as seen in the photo above). Fortunately, companies like LG are coming out with ways to screen the units, like their Art Cool line (featured in the first photo and in the image below) which includes a picture frame cover for your own custom art piece. Ductless heat pumps are also very quiet and can be purchased for both heating and cooling or just cooling only. If you already have a heating system but want to get ride of your clunky and inefficient window unit, this could be a great solution!
Mini-splits can be more expensive up front (about twice as much as a standard window unit), but their efficiencies, ease of installation in an existing building and better security (no window required!) make them an attractive option.
(Images: 1. Jeff Andrews Design, 2. Mitsubishi, 3. HVAC Distribution)