What HSPF2 Should My New Heat Pump Have?
Discover how a heat pump’s HSPF2 rating affects your comfort, reduces your carbon footprint, and why a Trane heat pump system is the way to go.
By Anne Fonda
If you’re asking this question, you already know about the benefits of an air source heat pump and electrification. Replacing an oil or gas furnace with a heat pump reduces carbon emissions and can provide more stable utility bills.
In this article, we will focus on using an electric heat pump to heat your home. For more extensive information about heat pumps and electrification, visit our Electrification Hub.
What is HSPF?
HSPF stands for Heating Seasonal Performance Factor. In a nutshell, it’s a measurement of how efficient an electric heat pump is at heating. In general, the higher the HSPF2 rating, the more efficient the heat pump is during cold weather.
Heat pumps with a high HSPF2 rating usually also have a higher Seasonal Energy Efficiency Ratio (SEER2). The most efficient systems will cost more upfront, but should save you money on your heating and cooling bills for years to come.
How is HSPF2 calculated?
HSPF2 is calculated by dividing the total heating output of a heat pump during the heating season by the total amount of electricity the heat pump uses.
All Trane heat pumps undergo rigorous third-party testing through the Air-Conditioning, Heating, and Refrigeration Institute (AHRI). AHRI Certification helps ensure our electric heat pumps and other products perform consistently and at the efficiency level advertised.
Heat pumps must be paired with an appropriate indoor unit to achieve the highest efficiency.
HSPF vs HSPF2
In 2023, the Department of Energy (DOE) refined the testing procedure for determining HSPF, resulting in the creation of HSPF2, a more accurate scale to measure heat pump heating efficiency.
The minimum HSPF2 allowed is 7.5 or higher for split system heat pumps and 6.7 or higher for single-packaged heat pumps. The HSPF2 ratings on Trane split-system heat pumps range from 7.5 to 11, and our single-packaged heat pumps have an HSPF2 of 7 to 8.1.
Is 10.5 HSPF2 good?
Yes. A heat pump with an HSPF2 of 10.5 is very efficient at heating. An 8.5 HSPF2 qualifies for a high-efficiency rebate qualification, so a 10.5 HSPF2 unit goes above and beyond. Such a heat pump will utilize inverter technology to overspeed the compressor to boost heating capacity significantly during low ambient temperatures.
For example, the Trane 20 TruComfort™ Heat Pump with WeatherGuard™ has an HSPF2 of 10.5. This heat pump is tested to provide a 70% heating capacity ratio at 5° F and delivers 100% heating capacity down to 32° F.
At what temperature do heat pumps become less efficient at heating?
While heat pumps are better than ever at heating in colder temperatures, in general, traditional heat pumps become less efficient when the temperature drops below freezing. If you live in an area with mild winters, a traditional heat pump and air handler system should suit your needs.
Do I still need a furnace if I get a heat pump?
Maybe. If you live in an area with colder winters, it makes sense both comfort-wise and financially. Many of our top engineers and product managers pair a heat pump with a furnace for backup heat.
“Our advice is to install a heat pump even when installing a gas furnace. This is called a hybrid heat system, and just like a hybrid car or truck, it will operate on electricity most of the time and switch to the gas furnace whenever the temperatures get cold enough that it is needed.”
– Mark Woodruff, Senior Product Manager, Ducted Outdoors
This hybrid operation is very efficient, and the cost of this type of system is not significantly different from a non-hybrid system.
What heat pumps qualify for the heat pump tax credit?
In case you didn’t know, the Inflation Reduction Act (IRA) of 2022 has financial incentives for upgrading your HVAC system to a more efficient system. The heat pump tax credit for qualified units is $2,000. The tax credit for qualified furnaces and AC units is $600. These tax credits are available on qualifying systems installed before December 31, 2025.
Currently, Trane is the only manufacturer with a full portfolio of residential heat pumps that meet both ENERGY STAR® and tax credit requirements, including single-stage, two-stage, multi-speed, and variable-speed heat pumps.
To qualify for the $2,000 tax credit and federal rebates under the Inflation Reduction Act (IRA) of 2022, heat pumps must meet HSPF2, SEER2, EER2, and COP efficiency ratings as shown in the table below.
| PRODUCT | SEER2 | EER2 | HSPF2 | COP at 5° F | CAPACITY RATIO |
| Air Source Heat Pump (Path A) | ≥16 | ≥9.8 | ≥8.5 | ≥1.75 | ≥60% (5° F/47 ° F/) |
| Air Source Heat Pump (Path B) | ≥16 | ≥11 | ≥8 | ≥1.75 | ≥45% (5° F/47 ° F/) |
| Packaged Heat Pumps | ≥15.2 | ≥10 | ≥7.2 | ≥1.75 | ≥45% (5° F/47 ° F/) |
If you install a qualified gas furnace as part of a hybrid heating system, you can bump your total tax credits up to $2,600. When you submit your tax return for the year you had the system installed, you claim the credits you qualified for. You’ll need proof of purchase and the AHRI certificate from the dealer.
What about cold climate heat pumps?
A cold climate heat pump (CCHP) is specifically designed to heat more efficiently even in frigid temperatures. Trane participated in the Department of Energy’s (DOE) Cold Climate Heat Pump Challenge. Our prototype exceeded the DOE’s requirements – When tested at the DOE’s lab, Trane’s CCHP prototype performed in temperatures as low as -23° F, surpassing the mandatory -20° F DOE requirement.
We’re in the product development phase now, where our engineers are working on the design optimization to make it super reliable, cost-effective, and an energy-efficient heating system for cold climates.
Early installations in cold climate applications are successfully satisfying home heating requirements even down to -20°F (no backup heat) with up to 4 ft of snowfall. Trane engineering has also developed proprietary algorithms to ensure reliable and efficient control relative to traditional vapor injection CCHPs, moving the CCHP concept forward with a simpler, more service-friendly design. Trane's new CCHP will be available in 2026.
“We’re really excited about this. We feel it can be a real game-changer for homeowners in northern states who never thought a heat pump system could work for them.”
– Chelsea Hudson, Product Manager, Ducted Variable Speed Outdoor
While final performance specifications are yet to be defined, the goal will be to provide electrification of heat to as many homes as is economically viable for all stakeholders, and to promote more widespread adoption of heat pumps across the country.
Why choose a Trane heat pump system?
Trane has been named America’s Most Trusted® HVAC Brand by Lifestory Research for 11 years in a row. In addition, 78% of homeowners with a Trane HVAC system would purchase a new Trane system when the time comes for HVAC replacement.
“Trane has always been an industry leader - we made heat pumps reliable in the 70s when the oil crisis made electric heating attractive compared to fossil fuels. We have over 60 years of engineering expertise in making heat pumps a reliable heating and cooling solution.”
– Jason LeRoy, Director of Advanced Technology, Trane Residential
In addition, here are some things that set Trane apart.
- Superior reliability. Products undergo the equivalent of 5 years of operation in 16 weeks in our Highly Accelerated Life Testing SEET lab, which simulates harsh weather and other operating conditions. It is hard to stop a Trane, after all.
- Industry-leading warranties. Registered Limited Warranty Period: Compressor, Outdoor Coil, Parts – ten (10) years.
- Communicating technology. Some of our premium systems incorporate the Trane Link™ Communicating System Controller and Smart Thermostat. Your heat pump system will automatically charge, configure, and calibrate for optimal performance year-round.
- Trane Diagnostics. With a Trane smart thermostat, you can opt in to Trane Diagnostics, which lets your Trane dealer monitor your system remotely. They stay on top of system maintenance and alert you to any issues. This can save time and money, and even help prolong the life of your system.
Work with the HVAC sustainability experts
Interested in learning how converting from a gas furnace heating system to a heat pump system could work in your home? Your local Trane dealer can help you explore your options and choose an all-electric heat pump system or hybrid heat system, depending on your climate.
Contact your local Trane dealer today for a consultation. Be sure to ask about systems that qualify for federal tax credits and heat pump rebates.
Anne Fonda, Content Writer
A Content Writer with Trane Technologies, Anne Fonda researches topics and writes for Trane® and associated residential HVAC brands. She works in collaboration with Trane Technologies subject matter experts, offering easy-to-understand, informative content on complex topics. Her goal is to help consumers make informed decisions on the products and services they need.
She has written for HVAC and other service provider websites for over 16 years. Before transitioning to web content writing, Anne had a 14-year stint as an award-winning journalist. She graduated cum laude from the University of Missouri-Columbia School of Journalism.
When she’s not working, Anne enjoys playing word games, reading, gardening, spending time with family, and visiting gardens and museums.
Expert review by Chelsea Hudson, Product Manager, Ducted Variable Speed Outdoor
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