Heating and cooling # HVAC efficiency: SEER2, EER2, HSPF2 and AFUE HVAC efficiency metrics changed on January 1, 2023: SEER became SEER2, EER became EER2 and HSPF became HSPF2, under a more realistic DOE test procedure. DOE states the old and new ratings are not directly comparable, so compare SEER2 against SEER2 and ask for the AHRI reference number. Split AC, national minimum 13.4 SEER2 Split heat pump 14.3 SEER2 Heat pump heating 7.5 HSPF2 In force since 2023-01-01 **Jurisdiction notice. **Efficiency standards, refrigerant rules, incentives, and licensing are set federally, by region, and by state, and they change. This page reflects DOE guidance of October 5, 2022 and 10 CFR 430.32 as of 2026-08-17. Verify before purchasing. ## Why can't efficiency numbers from before 2023 be compared with today's? On January 1, 2023 the Department of Energy changed the test procedure for central air conditioners and heat pumps. The new procedure tests at a higher external static pressure, to better reflect how equipment actually behaves once it is installed in a real house on real ductwork. Results are published under new names: **SEER2**, **EER2** and **HSPF2**. DOE states the consequence plainly: "Although SEER2, HSPF2, and EER2 ratings are similar to ratings using the original metrics, they are not directly comparable. Compliance with the new standards for each model must be determined based on its measured SEER2, HSPF2, or EER2." That matters the moment you are holding three bids. A 2019 article saying "16 SEER is good efficiency" cannot tell you whether a quote reading "15.2 SEER2" is good, bad or identical. They are not the same scale, and the article is not wrong so much as *on a different ruler*. ## Do you publish a SEER to SEER2 conversion factor? No, and that is deliberate. We do not publish a SEER-to-SEER2 conversion factor. DOE states that ratings on the new metrics are "not directly comparable" to ratings on the original metrics, and that compliance must be determined from the measured SEER2, EER2 or HSPF2 value. Approximate multipliers circulate widely, but they vary by equipment type and configuration, and using one to compare an old article's number against a number on today's quote is how homeowners end up believing they were offered less efficiency than they were. Compare like with like: ask for the SEER2 figure, and check it against the AHRI certificate. ## What are the current federal minimum standards? Nationwide minimum standards for units manufactured on or after 2023-01-01. Source: DOE. Product classSEER2HSPF2 Split-system air conditioners 13.4 — Split-system heat pumps 14.3 7.5 Single-package air conditioners 13.4 — Single-package heat pumps 13.4 6.7 Small-duct, high-velocity systems 12 6.1 Space-constrained air conditioners 11.7 — Space-constrained heat pumps 11.9 6.3 These nationwide standards apply based on the unit's **date of manufacture**. ## Why might a model be legal to install in one state but not another? Because alongside the nationwide standards there are regional standards, and they apply only to **air conditioners** — split-system and single-package. Regional standards do not apply to heat pumps. A heat pump only has to meet the nationwide standard, wherever it is installed. Regional standards for split-system and single-package air conditioners. Source: DOE. CapacityMetricNorthSoutheastSouthwest less than 45,000 Btu/hr SEER2 13.4 14.3 14.3 EER2 — — 11.7 / 9.8 45,000 Btu/hr and above SEER2 13.4 13.8 13.8 EER2 — — 11.2 / 9.8 single-package units — air conditioners EER2 — — 10.6 - The 11.7 EER2 standard applies to products with a certified SEER2 less than 15.2. The 9.8 EER2 standard applies to products with a certified SEER2 greater than or equal to 15.2. - The 11.2 EER2 standard applies to products with a certified SEER2 less than 15.2. The 9.8 EER2 standard applies to products with a certified SEER2 greater than or equal to 15.2. **Here is the part that catches people out:** In the Southeast and Southwest, the standard for split-system air conditioners is based on the date of installation. A unit installed on or after January 1, 2023 must meet the new standard. It is illegal for a contractor to install a product that does not meet the regional standard. The North works differently. In the North, the standard is based on the product's date of manufacture. A unit manufactured before January 1, 2023 may still be installed in the North after that date, as long as it complied with the standards in effect before January 1, 2023. The legal definition of "installation" (10 CFR 430.2) is: "Installation of a central air conditioner" means the connection of the refrigerant lines and/or electrical systems to make the central air conditioner operational. If you believe an air conditioner was installed illegally in the Southeast or Southwest, DOE takes reports at EnergyEfficiencyEnforcement@doe.gov. ## What is the AHRI reference number, and why should it be on your bid? A rated efficiency applies to a matched system — a specific outdoor unit with a specific indoor coil and, often, a specific air handler or furnace. Pairing a new outdoor unit with a mismatched indoor unit does not deliver the rated efficiency, and in the Southeast and Southwest it may not be a legal installation at all. The AHRI reference number identifies the certified combination, and it should appear on your bid. ## How much does a higher SEER2 actually save? The shape matters more than the absolute figures: the saving from each additional SEER2 point shrinks as you climb. Substitute your own capacity, run hours and rate. One season of cost against SEER2, with the formula stated. Illustrative — substitute your own figures. Show the data behind this chart One season of cooling cost: 36,000 Btu/h, 1,200 run hours, $0.17/kWh. SEER2kWh Cost 13.4 3,224 $54814.3 3,021 $51415.2 2,842 $48316 2,700 $45918 2,400 $40820 2,160 $36722 1,964 $334 ## What actually drives the cost? We publish no national average price, and the reason matters: an average across every house, region and system type is not a number you can act on. A replacement that includes duct modification, an electrical upgrade and a permit is a different job from a straight swap, and both read as "system replacement" on a one-page proposal. What actually drives your number: - **Equipment capacity and tier**, which should come from the Manual J rather than the old nameplate. - **The ducts** — whether they can move the air the new equipment needs, and what it costs if they cannot. - **Electrical work**, if a circuit or panel change is required. - **Permit and inspection**, usually required. - **Refrigerant** — current equipment uses R-454B or R-32; remaining pre-2025 R-410A stock may price differently. [What a bid should itemise](https://hvacbuddy.shop/costs/) · [operating cost calculator](https://hvacbuddy.shop/calculators/). ## Which efficiency numbers can you actually compare? If you are comparing efficiency figures, check which generation they belong to first. On January 1, 2023 DOE changed the test procedure and renamed three metrics: SEER became **SEER2**, EER became **EER2**, and HSPF became **HSPF2**. The current procedure measures at a higher external static pressure, much closer to what equipment meets once installed in a real house on real ductwork. DOE is explicit about the consequence: "Although SEER2, HSPF2, and EER2 ratings are similar to ratings using the original metrics, they are not directly comparable. Compliance with the new standards for each model must be determined based on its measured SEER2, HSPF2, or EER2." In practice: a SEER figure from a 2019 article cannot tell you whether a quote reading SEER2 is good, bad or identical. That is why we publish no conversion factor. We do not publish a SEER-to-SEER2 conversion factor. DOE states that ratings on the new metrics are "not directly comparable" to ratings on the original metrics, and that compliance must be determined from the measured SEER2, EER2 or HSPF2 value. Approximate multipliers circulate widely, but they vary by equipment type and configuration, and using one to compare an old article's number against a number on today's quote is how homeowners end up believing they were offered less efficiency than they were. Compare like with like: ask for the SEER2 figure, and check it against the AHRI certificate. The nationwide minimum for a split-system air conditioner is 13.4 SEER2, and for a split-system heat pump 14.3 SEER2 with 7.5 HSPF2. [What each metric measures](https://hvacbuddy.shop/efficiency/) · [minimums by region and state](https://hvacbuddy.shop/efficiency/standards/). ## What should you know about refrigerant? Refrigerant circulates in a sealed loop. It is not consumed the way fuel or oil is, so a system that is low on charge **has a leak**. Adding refrigerant without finding and repairing that leak treats the symptom, vents the new charge over the following weeks, and costs you the same money again next season. It is also regulated. Only Section 608 certified technicians may purchase refrigerants intended for use with stationary refrigeration and air-conditioning equipment. The restriction covers ozone-depleting substances and non-ozone-depleting substitutes — including HFCs — in cylinders, cans or drums. Wholesalers must record the purchaser's name, the date of sale and the quantity. There is one exception that confuses people: small cans of refrigerant for *vehicle* air conditioning are still sold without certification. That exception is for cars and does not extend to the equipment in your house. For new equipment, the 700 GWP limit in force since January 1, 2025 is why current systems ship with R-454B (GWP 465) or R-32 (GWP 675) rather than R-410A (GWP 2088). R-410A inventory built before 2025 can still be legally installed — EPA removed the installation deadline on May 21, 2026. [The full timeline](https://hvacbuddy.shop/refrigerants/). ## How is the right equipment size decided? Nearly every persistent comfort problem traces back to equipment size, and size is decided before the first box arrives. The standard is the ACCA **Manual J** load calculation (ANSI/ACCA 2 Manual J - 2016), which totals the heat gain and loss of your specific house: orientation, window area and type, insulation levels, air infiltration, internal gains, and your local design temperature. What a Manual J is *not*: square feet per ton, and not the old unit's tonnage. The first ignores everything that makes one house different from another. The second assumes whoever sized the old equipment got it right, and propagates their error for another fifteen years. Oversized equipment reaches the setpoint and shuts off before it has dehumidified, so the house ends up cold and clammy at the same time. Every start is also the hardest moment in a compressor's life, so wear accelerates. And you pay for the surplus capacity twice — once to buy it and again to run it. Ask for the completed Manual J in writing, not the claim that one was done. [What it contains and how to read it](https://hvacbuddy.shop/sizing/manual-j/). ## How can you verify any of this yourself? Everything regulatory on this site traces to a primary source and carries the date it was read: DOE for efficiency standards, EPA for refrigerants and Section 608, the IRS for tax credits, and ACCA for load calculation. The sources for this page are listed at the end with the date each was consulted. If you find a different figure elsewhere, check two things before deciding which to believe: whether the page says which generation its efficiency metric belongs to, and whether it carries a visible review date. Most of the outdated content in this category fails both tests. Sources (3) - U.S. Department of Energy — [Central Air Conditioners — Conservation Standards guidance (Final, October 5, 2022)](https://www1.eere.energy.gov/buildings/appliance_standards/pdfs/2023_CAC_Standards_FAQ_10-5-2022_Final.pdf) (accessed 2026-08-17) - Code of Federal Regulations — [10 CFR 430.32(c) — Energy conservation standards for central air conditioners and heat pumps](https://www.ecfr.gov/current/title-10/section-430.32) (accessed 2026-08-17) - Air Conditioning Contractors of America — [Manual J Residential Load Calculation — technical manuals](https://www.acca.org/standards/technical-manuals/manual-j) (accessed 2026-08-17) By [HVACBuddy Editorial Team](https://hvacbuddy.shop/authors/editorial-team/). Last reviewed: 2026-08-18. Verified: 2026-08-17 HVACBuddy publishes independent information. We do not install or service equipment, we do not dispatch contractors, and we do not sell leads. Nothing here is engineering, tax, or legal advice.