![]() A protective roof will be installed as well. It draws air from a three-season porch that has glass panels installed in the winter, pulling air up through the gaps in the floorboards. The compressor for this Kennebunkport, Maine, home is set up high on a stand on the south side of the house. If the evaporator is located so snow can easily be sucked into it, the compressor will spend a great deal of its time melting snow and not heating the house. ![]() There is no gain of latent heat here, only energy consumption to melt the snow out. What can drastically reduce the performance of a heat pump, though, is when the evaporator gets plugged with snow. The energy balance of this evaporator freeze/thaw cycle isn’t all that bad because the ice releases heat as it changes phase. The melt-water drains out under the unit and sometimes forms a small glacier. This ice is melted off during the defrost cycle. ![]() In normal operation, the evaporator will freeze moisture from the air, which takes some extra energy. It also needs to be well protected by a roof or cover that does not restrict airflow but doeskeep snow off and away from the unit. The outdoor compressor unit needs to be mounted at least two feet above the ground here in snow country. Let it snow-but not on your outdoor unit! If you like a dead-silent house, a mini-split isn’t for you. Make sure you can live with it before you install one. The interior unit makes noise-not a lot, but a varying level of whoosh. (At the 50° setting, the interior units typically keep air circulating constantly to prevent overly cold spots from developing.) 3. I set the temperature to 60☏ whenever the house is unoccupied temporarily or at night and down to 50☏ for extended periods of no occupancy. The big pile of snow on the left had just slid off the roof cover.Īlso, remember that a heat pump doesn’t have the capacity to quickly bring a cold house up to temperature. The compressor in the Massachusetts house is located on the east side of the house and has a shed roof installed over it. During periods of lower temperatures, use simple electric resistance heating or another source to make up the difference. ![]() I recommend sizing the heat pump to meet heating load at, say, 10☏. Heat-pump output drops as the outdoor temperature drops. Size it right for typical low temperatures Improve the thermal envelope of the structure to minimize the size you’ll need and to reduce overall energy use. I have a 5.4 kW PV array that supplies about 200% of my electrical consumption, including that of the heat pump, so the heating system is very “green.” I have since installed mini-splits in two other houses.īelow are my suggestions for successful house-heating with a mini-split-even in a cold, Northern New England climate like mine. So far this winter, from October 2012, to March 23, 2013, the usage has been 1,501 kWh. We can provide building science expertise, building investigations, and more. Have questions? BuildingGreen's experts are available to help. Get BuildingGreen's support on your project For the warmer winter of 2011–2012, the usage was only 1,247 kWh from September 2011 to April 2012. It has been a great success.ĭuring the winter of 2010–2011, the heater for my 1,500 ft 2 home consumed 1,757 kWh from October 2010 to June 2011. Three years ago, I installed a ¾-ton Fujitsu model air-source mini-split heat pump to heat my historic 1790 cape home here in Northfield, Massachusetts. Photo: Peter Talmage Mini-splits in cold climates? Yes we can! The interior unit is 18" off the floor, and certain creatures like that very much. This is in its third season as the primary heater for our 1,500 ft2 home in Northfield, Massachusetts. The wood fuel was “free” off my land, but burning it was a very dirty business in many ways. I have heated my various homes with wood since 1975.
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