Understanding SEER2, EER2, and HSPF2
In 2023, the U.S. Department of Energy began using updated test procedures and the SEER2, EER2, and HSPF2 metrics for covered residential central air conditioners and heat pumps. The newer tests use different conditions, including higher external static pressure for many ducted systems. That means a legacy SEER or HSPF number should not be compared directly with a current SEER2 or HSPF2 number as if the labels used the same test.
Last reviewed July 2026. See the DOE central air-conditioner and heat-pump standards page.
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 current ratings mean
SEER2 measures seasonal cooling efficiency, EER2 measures cooling efficiency at a defined high-load condition, and HSPF2 measures seasonal heat-pump heating efficiency. Higher values indicate greater rated efficiency within the same metric and product class.
There is no single consumer conversion that accurately crosswalks every old rating to a current one. Compare complete matched systems using the current rating standard and the manufacturer's or AHRI-rated combination. A lower-looking SEER2 or HSPF2 number does not by itself mean the newer equipment is less efficient.
For split-system central air conditioners below 45,000 Btu per hour, the national minimum is 13.4 SEER2, which is the standard that applies in New Hampshire. Split-system heat pumps have a national minimum of 14.3 SEER2 and 7.5 HSPF2. Other product classes have different thresholds, so verify the exact equipment category.
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.
How to choose a useful efficiency level
Higher ratings can reduce operating energy, but the best value depends on cooling and heating use, equipment cost, matched-system performance, rebates, comfort features, and installation. Current incentive programs may use thresholds above the federal minimum. A.J. LeBlanc Heating confirms the exact matched rating and current program requirements on the quote.
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 or call 603-623-0412. 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.
Why does my existing equipment still show SEER or HSPF?
Equipment rated under the earlier test keeps its original label. Current covered systems use the newer metrics, but the exact standards and enforcement rules depend on product class and date of manufacture or installation.
How much does a higher SEER2 unit cost vs a baseline one?
Highest-efficiency variable-speed units cost more installed than baseline single-stage equipment; contact us for current pricing on your specific situation. 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.