Heating Seasonal
A ratio of BTU heat output over the heating season to watt-hours of electricity used. The higher the HSPF rating of a unit, the more energy efficient it is. HSPF2 is an updated rating, similar to HSPF, but with updated testing requirements that better reflect real-world installations. A component in a heat pump that controls motor speed to increase the system’s energy efficiency and deliver more consistent comfort in the home. A conventional furnace or air conditioning unit switches repeatedly between on or off, and the continual stopping and starting uses a significant amount of energy. Conversely, the inverter in a variable speed compressor allows for a full range of operation, similar to the accelerator in a car, and automatically adjusts output for optimal efficiency. Copper piping which carries the refrigerant and connects the outdoor heat pump to the indoor unit. A mini-split is a ductless heat pump system where the outdoor compressor is typically smaller and has a fan that discharges to the side instead of the top. For entire-home comfort, there may be multiple indoor units that connect to one outdoor unit. For homes that just need added comfort to one room/area, there will be one outdoor unit and one indoor unit in the room/area needing the added comfort. The outdoor compressor is sometimes referred to as a “suitcase compressor” as they are shaped more like a traditional suitcase, rather than a cube.
Performance Factor (HSPF and HSPF2)
Inverter
Line Sets
Mini-split
Multi-Split
See Multi-Zone.
Also referred to as a multi-split, this typically has multiple indoor air handlers or ductless mini-split heat pump heads per single outdoor compressor, usually one in every high-use room. The rating of a unit’s cooling output during a typical cooling season divided by the total electric energy input during the same period. The higher the unit’s SEER rating, the more energy efficient it is. SEER2: SEER2 is an updated rating, similar to the SEER, but with a few more testing requirements, ideally making the rating more realistic when compared to real-world installations. Instead of one outdoor unit connected to multiple indoor air handlers, a ductless single-zone heat pump (a mini-split) is a single compressor connected to a single indoor air handler. The temperature at which the heating system switches from using the heat pump to using the backup heating system. This can be based on the Economic Balance Point, the Thermal Balance Point, or set somewhere between the two. The outdoor air temperature where the heat pump can no longer meet the heating needs of the home. The thermal balance point is sensitive to the size of the heat pump and its ability to retain heating capacity at lower temperatures. Better insulated and sealed homes will allow for a lower thermal balance point.
Multi-Zone
Seasonal Energy Efficiency Rating (SEER and SEER2)
Single-Zone
Switchover Temperature
Thermal Balance Point
Two-Stage Heat Pump
Any air source heat pump with two distinct stages of both heating and cooling operation.
Variable Speed Drive
See Inverter.
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ELECTRIC HEAT PUMP CUSTOMER BUYING AND OPERATION GUIDE FOR SINGLE-FAMILY HOMES
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