A heat pump may be one of the most energy-efficient ways to heat and cool homes, since they use no fuel other than electricity. Heat pump performance is measured by HSPF and SEER, the acronyms for heating season performance factor and seasonal energy efficiency ratio. The U.S. Department of Energy has established a minimum 7.7 for the HSPF and 13 for the SEER.
The method for determining the SEER involves running the heat pump when outdoor temperatures are 82 degrees to cool a room to 80 degrees with 50 percent humidity. Another measure of cooling efficiency is the EER (energy efficiency ratio), determined by running the heat pump when it’s 95 degrees to reach an indoor temperature of 80 degrees with 50 percent humidity. In general, SEER shows performance over an entire cooling season, while EER shows performance during the hottest periods. When the SEER and EER numbers are higher, the heat pump cools more efficiently.
In our climate, paying attention to a HSPF rating is particularly important. The average temperature that heat pump manufacturers use is 47 degrees for testing purposes, but our winter temperatures can be much lower. You can get better winter heat pump performance from a system with a scroll compressor or a dual fuel heat pump system. Each of these systems has its own advantages.
A scroll compressor creates up to 15 degrees warmer air indoors than a standard heat pump and also may last longer since it works more efficiently. A dual fuel heat pump is one that works in tandem with a furnace, so when temperatures drop into the 30s and the heat pump begins losing its heating efficiency, the system shifts over to natural gas or propane heating with the furnace. These lower the cost of heating, since you can use the more efficient heat pump when it’s mild and rely on fuel only when it’s cold. A system like this saves you during the fall and spring, since you only have to use the furnace back-up for the coldest weather.
If you’d like more information on heat pump performance, contact Ernst Heating & Cooling. We’ve provided HVAC services to the Metro-East area since 1951 and will be happy to answer any of your questions.
Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about heat pump performance and other HVAC topics, download our free Home Comfort Resource guide.