If you are going to install a central heat pump system in your home, pay close attention to its sizing.
The heat pump should be sized according to the house's heating and cooling loads.
Over-sized or under-sized heat pumps will cause short-cycle problems; the equipment will turn on and off too shortly, causing higher energy consumption and temperature swings. The problems are similar to those of air conditioners, furnaces and other central heating and cooling systems.
A wrongly sized heat pump can also disrupt the de-frost mechanism or the timings at which the electric resistance elements of the heat pump are activated, contributing to energy waste.
Also do not forget that the size of your home's ducts is a critical factor.
Heat pumps circulate high amounts of air at relatively low temperatures, which requires larger ducts than central furnaces or boilers.
Even if the heat pump is properly sized for the hottest days or for the hottest part of the days, it will be oversized for other periods.
And since there are always more hours and days of moderate temperatures than there are of extreme temperatures, the contractor should have it into account.
Oversized heat pumps will be unable to maintain an healthy moisture control - a key factor in hot-humid conditions.
Multi-stage geothermal heat pumps
New multi-stage heat pumps have variable speed motors that overcome a significant part of the problems mentioned above.