ENVIRONMENTAL CENTS: Understanding Heat Pumps
Understanding heat pump ratings and efficiencies can have a significant impact on your energy costs.
By Bruce Saller
COLUMNIST
Heating and cooling our homes is our highest use of energy according to the U.S. Energy Information Administration. In our climate, heat pumps are an efficient heating and cooling solution. There are two efficiency ratings for a heat pump:
SEER - Seasonal Energy Efficiency Ratio. Average cooling output in British Thermal Units per Watt-Hour (BTUs/WH). Since 1 WH = 3.4 BTU, a unit with a 17 SEER removes 5 WH of heat for every 1 WH of power (Coefficient of Performance (COP) of 5). A 16 SEER unit will use 25% more energy than a 20 SEER unit.
HSPF – Heating Seasonal Performance Factor. Average heating output in BTUs per WH. A unit with an 8.5 HSPF provides 2.5 WH of heat for every 1 WH of power (2.5 COP). An 8 HSPF unit will use 25% more energy than a 10 HSPF unit. On the east coast, HSPF is calculated using weather around central Pennsylvania, so we will see better performance than the rated HSPF.
While cooling performance is fairly stable, heating performance changes significantly with temperature. My heat pump has a rated HSPF of 9.5 (COP of 2.8), but its COP is 4.5 at 62 degrees, 3.2 at 42, 2.8 at 32 and 2.65 at 22. It produces full heat at 42 degrees, but only 90% at 32, and 80% at 22.
Heat pumps have a backup resistance heater (about 100% efficient) that normally comes on for one of these reasons:
Emergency heat has been manually turned on.
The outside temperature is below a certain temperature.
The house has failed to achieve the thermostat set temperature within a certain amount of time or is colder than the set temperature by a certain number of degrees.
These are normally controlled by the thermostat. As installed, my thermostat was set to turn on the backup heat under 40 degrees, or if the thermostat did not reach room temperature within 15 minutes. I had the installer change them to 25 degrees/30 minutes and have not had any issues.
If you have a gas or oil furnace, consider installing a dual fuel heat pump which uses a gas/oil furnace instead of electric resistive heaters for auxiliary/emergency heat.
A new heat pump may be eligible for a federal tax credit of 30% up to $2,000 if installed by 12/31/2025. A rebate up to $400 is also available from Columbia Gas if you install a natural gas dual fuel heat pump.
Local Obituaries
To view local obituaries or to send a note to family and loved ones, please visit the link that follows.
Support Award-winning, Locally Focused Journalism
The FXBG Advance cuts through the talking points to deliver both incisive and informative news about the issues, people, and organizations that daily affect your life. And we do it in a multi-partisan format that has no equal in this region. Over the past year, our reporting was:
First to break the story of Stafford Board of Supervisors dismissing a citizen library board member for “misconduct,” without informing the citizen or explaining what the person allegedly did wrong.
First to explain falling water levels in the Rappahannock Canal.
First to detail controversial traffic numbers submitted by Stafford staff on the Buc-ee’s project
Our media group also offers the most-extensive election coverage in the region and regular columnists like:
And our newsroom is led by the most-experienced and most-awarded journalists in the region — Adele Uphaus (Managing Editor and multiple VPA award-winner) and Martin Davis (Editor-in-Chief, 2022 Opinion Writer of the Year in Virginia and more than 25 years reporting from around the country and the world).
For just $8 a month, you can help support top-flight journalism that puts people over policies.
Your contributions 100% support our journalists.
Help us as we continue to grow!
This article is published under Creative Commons license CC BY-NC-ND. It can be distributed for noncommercial purposes and must include the following: “Published with permission by FXBG Advance.”