choosing a heat pump
Domestic heat pump system. Image credit: Goodman Air Conditioning & Heating.
Before buying a heat pump system, you should carefully consider a number factors. Here are some of them to bear in mind.
Your local climate
A heat pump may be right for you if you live in a place where the temperature extremes are not too great. Generally, a heat pump will work effectively providing the temperature doesn't often get below freezing. Heat pumps like temperatures above about 40°F (4.4°C). However, even if your winter temperatures sometimes dip below freezing there are types of heat pump system, such as a dual-fuel heat pump, that can cope with this.
Initial costs versus operating costs
The biggest expense over the life of a heat pump (or any heating and cooling system) is not the cost of buying and installing it. It's the accumulated monthly cost of running it, year after year. Usually, as the efficiency rating of a unit goes up, so does the initial cost. However, as the efficiency rating goes up, the monthly cost to operate the unit goes down. You'll want to consider the importance of a high-efficiency system and the trade-off between your initial cost and the monthly operating costs. If you're planning on living in the same house five years or more, consider installing a more efficient system.
Size
To work most efficiently, a heat pump's heating and cooling capacity has to match your home's heating and cooling demands. An undersized system won't be able to keep your home comfortably cool and warm during summer and winter, respectively. An oversized system won't dehumidify properly and can make the house feel drafty in the winter; moreover, it will tend to cycle on and off too often, which will increase the wear on the equipment and decrease its efficiency. Heat pumps should be sized to run continuously to maximize efficiency. It is best to consult a qualified heat pump contractor to find out what you need.
Duct system
This is very important because the heat pump will pump air all through your house using this system. The ductwork must be insulated and sealed properly so the air gets where it's going at the right temperature. Proper construction of the ductwork is essential to ensure efficient operation of the heat pump over the life of the system. Care taken in the initial construction and sealing of the ductwork will yield maximum efficiency from the heat pump for years to come. Again, a qualified contractor is best placed to tell you whether you'll be able to use your existing ductwork or will need new ducts.