Learn about Upgrading the Heat Pump System for Your Home
Heat pumps are the part of heating/cooling systems that heat or cool the air in your home. Then, heat pumps circulate the air through a series of ducts. As a result, your home remains warm in the wintertime and cool in the summertime. Additionally, heat pumps are often installed as “split-systems”. In a split-system, the inside coil is part of the air handler and the outside unit (located outside of the home) absorbs or rejects heat to the outside air.
Heat pumps also are available as a single package unit, which contains all the components in a single enclosure or cabinet. However, because heat pump heating/cooling systems typically consume large amounts of electricity, homeowners must maintain an energy efficient home. Learn more about how a heat pump upgrade impacts your home comfort.
Types of Heat Pumps
Heat pumps come in two basic types: Air Source Heat Pumps and Geothermal Heat Pumps. Air source heat pumps, as their name suggests, are very common in mild to warm climates. These pumps rely on the outside air for heating and cooling your home. Conversely, geothermal heat pumps are not as commonly used. These pumps use ground water, a pond or lake to heat and cool your home.
Of the two basic types of heat pumps, air source heat pumps are less costly to install. Conversely, geothermal heat pumps maintain higher efficiencies. Fortunately, there are many options available when upgrading the heat pump system in your home including a range of:
Unlike many fossil-fueled heating systems, heat pumps use electricity to heat, cool and dehumidify your home.
Air Source Heat Pumps
New residential air source heat pumps require efficiency ratings in terms of Seasonal Energy Efficiency Ratio (SEER) for cooling. In addition, air source heat pumps require Heating Seasonal Performance Factor (HSPF) ratings for heating. A heat pump that operates at 15 SEER removes 15 BTU’s for each watt of electricity consumed. Conversely, a 10 SEER heat pump removes 10 BTU’s for each watt of electricity consumed. Similarly, a heat pump with a 9.0 HSPF supplies 9 BTU’s of heating to the home for each watt of electricity used. The higher the SEER and HSPF, the more efficient the air source heat pump. GreenHomes recommends heat pumps have a 15 SEER rating or higher and an 8.5 HSPF rating or higher when replacing an older air source heat pump system.
Geothermal Heat Pumps
For geothermal heat pumps, GreenHomes recommends a 17 EER (Energy Efficiency Ratio) minimum for a closed loop heat pump system and a 21 EER minimum for an open loop system. On the heating side, geothermal heat pumps should be a 3.6 COP (Coefficient of Performance) minimum for closed loop heat pump systems and a 4.1 COP minimum for open loop systems.
Finally, heat pumps often connect to distribution ductwork that is very leaky and uninsulated. Therefore, GreenHomes recommends homeowners seal and insulation the ductwork.
Heat Pump Sizing
Heat pump sizing relates to the amount of heating or cooling provided per hour (not the physical size of the heat pump). Additionally, British Thermal Units (BTU's) per hour express the size of a heat pump. The size of the heat pump needed depends on the efficiency level and the square footage of the house. Also, a home's climate impacts sizing. For example, a larger, leakier, poorly insulated house in a hot climate needs a higher BTU/hr heat pump. Conversely, a smaller, tighter, well insulated house in a warmer climate needs a lower BTU heat pump.
Due to the complexity of heating and cooling, heat pumps present difficulties in optimal sizing. GreenHomes recommends contractors perform a heating/cooling load calculation. Contractors determine heating and cooling loads based on the ACCA Manual J. Then, contractors should apply ACCA Manual S to properly size the heat pump. It is never acceptable for an upgraded air source heat pump to be sized based on the size of the older, existing equipment or by using “rules of thumb” to size the new heat pump system.