We get a lot of questions about heat pumps and how they are different from a conventional air conditioner/furnace system.
An air source heat pump is actually an outdoor unit and is placed where an air conditioner would be set in a conventional system. Unlike an AC, the heat pump is a work horse that goes year round. In the summer cooling season it is your air conditioning unit. In the winter heating season, it acts as your heating unit unless the temperatures are very cold. The heat pump has an outdoor thermostat that has a set point that switches your heat source from the more energy efficient heat pump to less efficient straight furnace heat (referred to as emergency heat or resistant heat) at these lower temperatures. This set point temperature is usually in the low 30s. The heat pump runs on electric power while the furnace inside can be electric or gas. Heat pumps were designed to save on energy costs by allowing you to use the air inside or outside of your home (depending on the season) to reduce energy costs.
In the winter, a heat pump uses electricity to capture the heat that is always present in the outdoor air and pumps it back into your home; a furnace has to heat the indoor air.
While a heat pump system can help provide greater savings on your heating bills, the components also work together to bring you more efficient cooling in the summer. In the cooling season, the heat pump functions as an air conditioner, pulling the heat out of your home and releasing it outdoors. In addition, the electric fan blower in the furnace helps circulate cool air from the heat pump throughout your space.
As with any type of system, the higher the efficiency rating of all of the individual components of the system, the better the install (including ductwork), the more suited the individual components are to each other (manufacturer, age, efficiency), the more cost savings will be realized. To reap maximum benefit, you would create a matched system featuring a 20 SEER, dual compressor heat pump with a 95% efficient, three stage, variable speed furnace.
Routine maintenance by a professional is also key to maintaining optimal cost savings over time so we always recommend an annual maintenance contract to protect your comfort investment and optimize your efficiency.
The one negative thing we hear about air source heat pumps is that the "heat is a cooler heat". Your thermostat will read the same temperature with a furnace or heat pump but the air coming out of your registers will feel "cooler" to some people. To research individual models, features and combinations, please visit www.americanstandardair.com.
Geothermal Heat Pumps
Geothermal heat pumps use the constant temperature deep in the ground to deliver the highest energy efficiency available. Rather than an SEER rating, geothermal heat pumps carry EER (energy efficiency ratio) ratings due to the fact that they maintain a constant efficiency. Many geothermal units can reach EERs of 30 to 32. To put this in perspective, a 13 SEER air source heat pump would carry an EER of about 10.8.
You may be wondering why everyone doesn't use geothermal given the efficiency availability. The main reasons are space and cost. Geothermal uses a series of underground loops or wells that are usually not compatible with standard subdivision lot sizes. As you might imagine, with the loops or wells, the installation of geothermal systems is much more expensive than an air source installation.
If you're interested in learning more about geothermal heat pumps, visit www.fhp-mfg.com.