Ductless Heat Pumps

he ductless heat pump is a new option for home heating that offers:

• Efficient operation at outside temperatures of 17°F and above without electric backup
• Quiet operation – both indoors and outdoors
• Heating and cooling
• Simplified installation

Ductless heat pumps are appropriate for both replacement of existing heating systems, especially baseboard/wall heaters, as well as for new construction. Ductless heat pumps have been installed in commercial buildings for more than 20 years and are available from many manufacturers.

Ductless heat pumps are very efficient for several reasons: Since the heated or cooled air is delivered directly to the room, ductless heat pumps avoid efficiency losses associated with ductwork – typically 15-20 percent. Variable speed compressor models, usually labeled “inverter technology,” avoid on-off cycling losses and are able to provide usable heat efficiency on all but very cold days. And, because they provide heat/cooling to specific areas of the house, they can be more efficient since each “zone” can be heated to the desired temperature.

Ductless heat pumps are sometimes called a “mini-split” heat pump and consist of an outside compressor unit and one more inside "heads" that deliver conditioned air to the room or rooms. Inside units are typically mounted high on the wall, but certain models can be recessed in the ceiling or even installed with a short duct run to serve adjacent rooms. The inside and outside units are connected by refrigerant lines, usually concealed in the walls or ceilings or under a cover on the outside of the house. Some models allow several indoor heads to be connected to a single outside compressor. Ductless heat pumps operate on the same principle as traditional heat pumps - using electricity to move heat between outdoor and indoor air by compressing and expanding a refrigerant. Most new ductless heat pumps use the newer, less environmentally-harmful refrigerant R-410a. Depending on the rated capacity, they require 110 or 220 volt AC power.

So-called "Mini-Split" because they tend to be smaller capacity (BTU/hour "Tonnage" rating) and because they are "Split system" with separate compressor (outside) and expansion heat delivery unit (inside) units, similar to traditional heat pumps, but unlike a through-the-wall unit, sometimes used to heat motel rooms.

A very quiet oscillating fan delivers conditioned air more evenly to all parts of the room. The indoor temperature and other settings, such as automatic night temperature setback are set with a hand-held remote control. Like any air conditioner in cooling mode they provide some dehumidification of the indoor air.