Understanding SEER2, EER2, and HSPF2
On January 1, 2023, the U.S. Department of Energy replaced the old SEER, EER, and HSPF efficiency ratings for residential air conditioners and heat pumps with the updated SEER2, EER2, and HSPF2 standards. The new tests measure the same equipment more realistically. For New Hampshire homeowners shopping for new cooling or heat pump equipment, the change matters because the new numbers look lower than the old numbers for the same physical unit, even though the equipment itself has not become less efficient.
At A.J. LeBlanc Heating, we help homeowners sort out the new numbers. Here is what the rating change means in practical terms.
Why the ratings changed
The old SEER, EER, and HSPF tests were standardized in 1992. They measured efficiency under idealized conditions that did not match what homeowners actually experience: low static pressure on the duct system, ideal indoor temperatures, controlled humidity. Modern homes have higher static pressure (more restrictive ductwork, higher-MERV filters) and more varied conditions than the original test method assumed.
The 2023 SEER2, EER2, and HSPF2 tests (called M1 testing procedures) raise the external static pressure used during testing, which produces a more realistic real-world efficiency number for the same equipment.
What the new ratings mean
SEER2 (Seasonal Energy Efficiency Ratio 2)
Measures average cooling efficiency across a typical cooling season. Higher is better.
- Old SEER 14 became roughly SEER2 13.4 for the same unit
- Old SEER 16 became roughly SEER2 15.2
- Old SEER 20 became roughly SEER2 19
- Federal minimum SEER2 for new central AC in the northern region (which includes NH) is 13.4
EER2 (Energy Efficiency Ratio 2)
Measures cooling efficiency at a single high-load operating point (peak conditions). Useful for comparing how equipment performs on the hottest days.
- Old EER 12 became roughly EER2 11.5
- EER2 matters for homes in hot climates and for sizing equipment that needs to handle peak loads reliably
HSPF2 (Heating Seasonal Performance Factor 2)
Measures heating efficiency for heat pumps over a typical heating season. Higher is better.
- Old HSPF 8.2 became roughly HSPF2 7.0
- Old HSPF 10 became roughly HSPF2 8.5
- Federal minimum HSPF2 for new split-system heat pumps is 7.5 (a national standard; regional minimums apply only to central AC)
- Quality cold-climate heat pumps achieve HSPF2 values of 9.0 to 11.0+
The percentage drops at a glance
- SEER2 values are roughly 4 to 5 percent lower than old SEER values for the same equipment
- EER2 values are roughly 4 to 5 percent lower than old EER values
- HSPF2 values are roughly 15 percent lower than old HSPF values
The drops are not because the equipment got worse. The test got more honest.
What this means when you are shopping
Comparing models
Compare ratings using the same standard. A new unit's SEER2 rating cannot be directly compared to an older unit's SEER rating on a spec sheet from 2020. Modern manufacturer literature typically lists both for transition clarity.
Tax credit eligibility
The federal 25C Energy Efficient Home Improvement Credit used specific SEER2, EER2, and HSPF2 thresholds to qualify equipment, but that credit ended for installations placed in service after December 31, 2025 and is not available for new installations in 2026. For incentives that are still live, the SEER2/HSPF2 numbers matter for the NHSaves rebates covered below.
NHSaves rebates
NHSaves utility rebates also use SEER2 and HSPF2 thresholds for qualifying equipment. Eligibility thresholds change periodically; confirm current rules with your utility or installer.
Real-world implications for NH installations
Beyond the numbers on the label, here is what produces the largest gap between rated and real-world efficiency:
- Equipment sizing. Oversized equipment short-cycles and underperforms its rated efficiency.
- Duct design and leakage. Even efficient equipment loses capacity to leaky or undersized ducts.
- Refrigerant charge. A unit that is slightly low on refrigerant runs at significantly reduced efficiency.
- Airflow. The static pressure across the indoor coil directly affects performance.
- Controls. Multi-stage or variable-speed equipment paired with a thermostat that does not use the staging will not deliver its rated efficiency.
Installation quality often matters more than the difference between SEER2 14 and SEER2 16 equipment.
Recommendations for southern NH homes
Reasonable targets for residential equipment:
- Central AC: SEER2 15+ for cost-conscious buyers; SEER2 18+ for higher-efficiency homes that run AC a lot
- Heat pumps (cooling rating): SEER2 16+
- Heat pumps (heating rating): HSPF2 9.0+ for general use; HSPF2 10+ for cold-climate cases
Schedule an equipment consultation
If you are evaluating new cooling or heat pump equipment for your NH home and trying to make sense of the rating change, contact A.J. LeBlanc Heating. Serving New Hampshire families since 1928.
Frequently Asked Questions
When did SEER2 take effect?
January 1, 2023. All new residential AC and heat pump equipment manufactured for sale after that date is rated under the new standards.
Did my existing AC become less efficient?
No. The equipment is exactly as efficient as it was before. The rating change is about the test procedure, not the equipment performance.
Can I still buy equipment with old SEER ratings?
No. All residential AC and heat pump equipment sold today is rated under SEER2/EER2/HSPF2; only older spec sheets still show the legacy ratings.
How much does a higher SEER2 unit cost vs a baseline one?
Roughly $1,500 to $4,000 more installed for the highest-efficiency variable-speed units over baseline single-stage equipment. The payback depends on cooling use and electric rates.
Does the federal tax credit require a specific SEER2?
The 25C federal tax credit did use specific SEER2, EER2, and HSPF2 thresholds, but it ended for installations placed in service after December 31, 2025 and is not available in 2026. NHSaves utility rebates still use SEER2 and HSPF2 thresholds; we track the current requirements and can confirm what qualifies before you purchase.