Heat pumps are quickly becoming the fastest-growing HVAC technology in the United States. Essentially, a heat pump functions like an air conditioner but includes a reversing valve. This valve allows the refrigeration cycle to run in reverse, enabling the heat pump to provide both heating and cooling. Their rising popularity is largely due to their impressive efficiency. However, not all heat pumps are created equal, and understanding heat pump efficiency ratings is key to comparing different models effectively.
British Thermal Units
Many countries throughout the world measure cooling and heating output in joules. In the U.S., output in joules is available, but the industry primarily uses British thermal units (BTUs) to size heat pumps. Additionally, many calculations to determine energy efficiency use output in BTUs as a variable. A BTU indicates the energy required to increase the temperature of 1 pound of water by 1 degree Fahrenheit. One BTU equals approximately 1,055 joules.
Tons
The U.S. HVAC industry also uses the tons: 1 ton equals 12,000 BTUs. A general guideline for homes is that you need between 10 and 30 BTUs for each square foot. To achieve a more precise estimate, your installer will perform a load calculation. The average U.S. home needs either a 4.0- or 4.5-ton heat pump. Heat pumps come in smaller and larger sizes as well, and you can twin systems for even greater output.
Seasonal Energy Efficiency Ratio (SEER)
The SEER rating is the primary way to measure the cooling efficiency of heat pumps and air conditioners in North America. What’s notable about SEER is that it estimates cooling efficiency over a season. This provides consumers with a more practical estimate of system efficiency. The higher the SEER rating, the cheaper cooling will be over the long term. To determine a system’s SEER, manufacturers test it in a lab. They measure the total heat removed in BTUs and divide it by the energy required in watt-hours.
SEER2
The SEER2 rating is a newer version that accounts for static air pressure in ducts. All new air conditioning units installed since Jan. 1, 2023 must comply with the new SEER2 efficiency standards from the U.S. Department of Energy (DOE). When comparing central heat pumps, use SEER2 ratings if they’re available. They’ll provide a more accurate assessment of efficiency.
Heating Seasonal Performance Factor (HSPF)
The HSPF rating is similar to SEER except that it measures heating efficiency over a winter. As with SEER, the higher the rating, the higher the efficiency. Both HSPF and HSPF2 ratings are available for the time being. Labs calculate HSPF similarly to SEER but measure the total heat added rather than the heat removed.
Note that the industry generally calculates HSPF at 47 degrees Fahrenheit. Traditional air-source heat pumps have cold-weather thresholds at which they’re no longer as efficient. If purchasing a stand-alone air-source heat pump (ASHP), you need to select a model with a low enough threshold for your climate. An alternative is a hybrid configuration, which pairs a heat pump and furnace.
Energy Efficiency Ratio
The EER and EER2 ratings are similar to SEER and SEER2. The main difference is that the goal with EER is to measure efficiency at peak performance. Labs measure EER with an ambient temperature of 95 degrees Fahrenheit. They use an internal temperature and relative humidity of 80 degrees and 50%, respectively. The SEER and SEER2 ratings are more useful for the average consumer.
Coefficient of Performance (COP)
The HVAC industry uses the COP to measure efficiency across various technologies, including refrigerators. In the consumer space, it’s often used to measure the heating efficiency of heat pumps. You can think of COP as a counterpart to EER and an alternative to HSPF. How accurate COP is depends on a wider range of factors. That means HSPF is more useful for the average consumer. That said, if you consistently run a heat pump at or beyond its cold-weather threshold, COP can give you better information.
Other Energy Efficiency Ratings
The SEER, SEER2, HSPF, and HSPF2 ratings are the most common heat pump efficiency ratings used in the U.S. Seasonal COP (SCOP) is an alternative to HSPF, whereas annual COP (ACOP) is an alternative to SEER. You may also encounter the annual EER (AEER) and integrated EER (IEER). The IEER provides a range of estimates, which can be useful in climates prone to sharp changes.
Energy related products (ERP) is a European rating system that seeks to measure efficiency within the context of eco-friendliness. The scale runs from A+++, the best, to G, the worst. APF ratings are another alternative to HSPF. You may also see the integrated and non-standard part-load value (IPLV, NPLV). IPLV and NPLV measure the combined cooling and heating efficiency of heat pumps. A notable difference is that the lower the rating, the more efficient the system.
Energy Efficiency Rating Minimums
In the U.S., the DOE is responsible for setting energy efficiency minimums. Once new minimums go into effect, manufacturers can no longer make heat pumps that fail to meet them. Note that the DOE breaks the country up into three regions: North, Southeast, and Southwest. In some cases, it sets different minimums per region to address the North’s higher heating needs and the greater cooling needs in the Southeast and Southwest.
EnergyGuide Label
The DOE requires all heat pumps and many other appliances to have an EnergyGuide label. It’s a yellow sticker found on the appliance and online. The label provides consumers with the information needed to assess efficiency. In the case of heat pumps, that includes SEER and HSPF ratings. Starting Jan. 1, 2023, manufacturers were required to include HSPF2 as well as SEER2. You’ll also find estimated watts used and electricity costs per season. Label guidelines require manufacturers to base cost estimates on national averages.
ENERGY STAR
ENERGY STAR is a joint effort between the DOE and the U.S. Environmental Protection Agency (EPA). The DOE sets energy efficiency minimums that are legal requirements for manufacturers. The EPA sets loftier minimums with an emphasis on environmental impact. Systems that achieve those higher standards earn ENERGY STAR certification. That certification provides consumers with confidence. It’s also the criterion for many energy incentives, including rebates and tax credits.
Heat Pump Installation Consultations in Farmington Hills
AJ Danboise Plumbing, Heating, Cooling & Electrical has served Farmington Hills, MI and the surrounding areas since 1925. Our company provides residential and commercial services, and we can help you choose the ideal heat pump for your location. Our NATE-certified technicians also install, maintain, and repair furnaces, boilers, ductless mini-splits, whole-home air cleaners, ultraviolet lights, and humidifiers.
We have licensed electricians available for inspections, installations, and repairs. That includes wiring, electrical panels, whole-house surge protection, standby generators, outlets, ceiling fans, and indoor and outdoor lighting. Our plumbers clean drains and upgrade and repair sewer lines. We also install and service water heaters, garbage disposals, sump pumps, and water treatment systems.
To schedule an appointment or get answers to your questions about our services or products, contact our team at AJ Danboise Plumbing, Heating, Cooling & Electrical today.
