Mini-Split Heat Pumps

Mini-Split Heat Pumps

Mini-split, wall mounted indoor heat pump.
Mini-split, wall mounted indoor heat pump. Image courtesy of Mitsubishi Electric

Mini-Split, Cold Climate Heat Pumps (CCHPs) are single room heaters, not a whole-house, central heating system.  They are well suited to smaller homes with an open floor plan.

Why is it so difficult to get a clear answer about the exact cold temperature limitation of CCHPs?

Because the answer will depend on: 1) Your geographic location, which determines your design day . 2) Your home’s heat loss as determined by the integrity of your building envelope (see How Cold is Too Cold for a Cold Climate Heat Pump?) and 3) The performance characteristics of your particular CCHP (see At What Temperature Will a Heat Pump Become Ineffective?)

During coldest winter temperatures auxiliary heat will be necessary to maintain indoor comfort.

The basic principle is that CCHPs become less efficient (and less effective at heating your home) as outdoor temperatures drop. Put simply this is because there is less heat in the outdoor air to convert to indoor heat. If your electric bill is too high, or you have cold areas around your home, here are your options for single-room auxiliary heaters:

Wall-vented gas heater

Direct-Vent Gas Heaters

Direct-vent gas heaters are efficient because the fuel is combusted right in the room where heat is needed, instead of ...
Electric Baseboard Heater

Electric Baseboard

Even though electric baseboard heaters work on resistance heat which does not have the leveraging effect of a heat pump, ...
woodstove

Wood Stove

Wood stoves in common areas work especially well with an open floor plan. In addition to the ambience and comforting lifestyle ...
Wood Pellet Stove

Wood Pellet Stove

A wood pellet stove has a few advantages over traditional wood stoves: A wood pellet stove doesn't need to be ...
Fireplace Inserts

Fireplace Inserts

A fire in your fireplace gives the room a comforting glow and does warm a small area. The EPA estimates ...
Fireplace

Fireplace

The warmth of an open fire resonates deeply in our species, but 90% of the fire heat goes up the ...
ceiling mounted electric heater

Miscellaneous Electric Heaters

There are a variety of electric resistance heat emitters on the market. Wall and ceiling mounted units are typically found ...

Design day

Your home’s heating system was designed to keep you comfortable on the theoretical coldest day of the year in your geographic region. The largest contributing factor for your design day is the difference in temperature between the inside and outside of your house; this is referred to as the “Delta T” value. A typical Delta T for the Northeast is 78-degrees, representing a day that is -10ºF outside and comfortable 68ºF inside the house. The two variables of geographic location and building performance will determine the quantity of heat needed to maintain comfort.

Figuring out the exact heat loss of a particular building is a complicated job for a heating professional.  Your contractor will complete a Manual J calculation, but for practical purposes, a three-year history of your heating bills will provide a good estimation.  If you want to drill down on heat loss calculations (hint: you don’t) here is a good article