One country, three efficiency standards: the regional SEER2 split

Which states are in the Southeast and Southwest regions?

The ones named in two footnotes. The regulation does not draw a climate map. It publishes two lists of names, as footnotes to a table, and everything else follows from them.

The first footnote to the table at 10 CFR 430.32(c)(6)(i) reads, in full: “Southeast” includes the States of Alabama, Arkansas, Delaware, Florida, Georgia, Hawaii, Kentucky, Louisiana, Maryland, Mississippi, North Carolina, Oklahoma, Puerto Rico, South Carolina, Tennessee, Texas, Virginia, the District of Columbia, and the U.S. Territories.

The second reads: “Southwest” includes the States of Arizona, California, Nevada, and New Mexico.

Read those two sentences slowly, because several of the names in them surprise people. Hawaii is in the Southeast. So is Delaware, and so is Maryland, and so is the District of Columbia.

Puerto Rico and the U.S. Territories are named in the 2023 list. They were not named in the 2015 one at § 430.32(c)(2), which is a real difference between the two generations of the rule and not a transcription slip.

Meanwhile Nevada and New Mexico, which contain some of the hottest inhabited places in the country, are in the Southwest rather than the Southeast, and pick up an EER2 requirement the Southeast does not have.

Everything not named in either footnote falls under the national standard alone. The regulation gives that remainder no name. The trade calls it the North; the CFR does not, and this page uses the word only for readability.

It is 30 of the 51 US jurisdictions: Alaska, Colorado, Connecticut, Idaho, Illinois, Indiana, Iowa, Kansas, Maine, Massachusetts, Michigan, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New Jersey, New York, North Dakota, Ohio, Oregon, Pennsylvania, Rhode Island, South Dakota, Utah, Vermont, Washington, West Virginia, Wisconsin, Wyoming.

HYRE analysis: the lists are not a climate zone map and were never meant to be one.

They are political boundaries drawn around a cooling-load argument, which is why Delaware and Hawaii sit in the same category, and why the line runs down the middle of shared metropolitan areas.

That matters most on a border (Delaware against Pennsylvania, Maryland against Pennsylvania, Kentucky against Ohio, Missouri against Arkansas), where two houses ten minutes apart are under different federal law.

Our Texas and Arizona guides read the rule against one state each.

What is SEER2, and how is it different from SEER?

SEER2 is the same measure as SEER, taken under a harder test. Both are seasonal cooling output in Btu divided by seasonal electrical input in watt-hours.

Under 10 CFR 430.23(m)(2) and (m)(3), SEER2 and EER2 are determined under appendix M1 to subpart B of 10 CFR part 430 and rounded to the nearest 0.025 Btu/W-h. The predecessor figures were determined under appendix M.

The change that did most of the work is a single line in Table 4 of each appendix: the minimum external static pressure the indoor blower must work against while the machine is being rated.

Appendix M set it by capacity: 0.10 inches of water up thru 28,800 btu/h, 0.15 inches of water 29,000 to 42,500 btu/h, 0.20 inches of water 43,000 btu/h and above.

Appendix M1 sets it by product variety instead, and for a conventional central air conditioner or heat pump the figure is 0.50 inches of water.

HYRE calculation: that is between 2.5 and 5 times the resistance the same blower faced under the old procedure, depending which capacity band the unit would have fallen into.

Appendix M1 also adds 0.08 inches of water for ducted units tested without an air filter installed, and sets a lower figure for the varieties that truly cannot produce that pressure: 0.10 for low-static equipment, 0.30 for mobile home and ceiling- or wall-mount units, and 1.15 for small-duct high-velocity systems.

HYRE analysis: a higher external static pressure is a better model of a real house.

Real ducts, real filters and real registers resist airflow; a blower working against 0.10 inches of water is being tested in conditions almost no installed system experiences.

The consequence is that a given machine, unchanged, rates lower in SEER2 than it did in SEER.

That is why the national floor fell from 13 SEER to 13.4 SEER2 and the regional floor from 14 SEER to 14.3 SEER2, while the requirement got no weaker.

A SEER number and a SEER2 number are not comparable and must never be put in the same column. Any page that tells you the minimum "went down in 2023" has made exactly that error.

To see what each step above the floor is worth on a bill, use the SEER2 savings calculator.

Is it illegal to sell a lower-rated unit, or only to install it?

The ban is on installing. Selling is an offense only when the seller knows where the unit is going. This is the part most often stated wrongly, and it changes who is liable.

The regulation does not have one rule. It has a manufacturing rule, a distribution rule and an installation rule, they bind different parties, and two of the three turn on knowledge.

Manufacture: Under 10 CFR 429.102(a)(6) it is a prohibited act for a manufacturer or private labeler to distribute in commerce any new covered product “that is not in compliance with an applicable energy conservation standard prescribed under the Act.”

That is what makes the national table at 10 CFR 430.32(c)(5) bite: from January 1, 2023 a manufacturer may not put a sub-13.4 SEER2 split air conditioner into commerce anywhere in the country.

Installation: The regional table is different in kind.

10 CFR 430.32(c)(6)(i) applies to products “installed on or after January 1, 2023” in the two regions, and 10 CFR 430.32(c)(6)(ii) states the consequence in one sentence: “Any model of outdoor unit that has a certified combination with a rating below the applicable standard level(s) for a region cannot be installed in that region.”

The trigger is the installation, not the sale and not the manufacture.

Sale: There is no free-standing federal ban on selling a lower-rated unit into a regional state. What exists instead is a set of knowledge-based offenses at 10 CFR 429.102(c)(1) to 10 CFR 429.102(c)(3).

For a distributor: “It is a violation for a distributor to knowingly sell a product to a contractor or dealer with knowledge that the entity will sell and/or install the product in violation of any regional standard applicable to the product.”

And: “It is a violation for a distributor to knowingly sell a product to a contractor or dealer with knowledge that the entity routinely violates any regional standard applicable to the product.”

For the installer: “It is a violation for a contractor or dealer to knowingly sell to and/or install for an end user a central air conditioner subject to regional standards with the knowledge that such product will be installed in violation of any regional standard applicable to the product.”

HYRE analysis: read those three sentences against each other and the design of the rule is clear. The manufacturing prohibition is strict: no knowledge element, no intent element.

The distribution and installation prohibitions are not: each is written around what the party knew.

A distributor who ships a compliant-elsewhere unit to an address in Georgia without knowledge of where it will be installed is in a different position from one who knows.

That distinction is invisible in every consumer summary of this subject we could find, and it is the whole architecture of the rule.

Who is not in that list: the homeowner: Every prohibited act in 10 CFR 429.102 is addressed to a manufacturer, private labeler, distributor, contractor or dealer.

The end user is named once in this whole scheme, at 10 CFR 429.154(a), and it is protective: “Any party found to be in violation of the regional standards may remediate by replacing the noncompliant unit at cost to the violator; the end user cannot be charged for any costs of remediation.”

Recommendation: if you are a homeowner who has discovered that a non-compliant unit was installed at your address, the codified remedy is replacement at the violator’s cost, and the regulation says in terms that you cannot be charged for it.

That is worth knowing before you accept a quote to put it right yourself.

Can air conditioners built before 2023 still be installed?

Outside the two regions, yes. Inside them, the text gives no exemption. Because the national standard is written against the date of manufacture and the regional one against the date of installation, the two behave completely differently at a changeover.

Outside the two regions, a unit manufactured before January 1, 2023 is simply not caught by 10 CFR 430.32(c)(5), which reaches products manufactured on or after that date.

Nothing in the regional paragraph applies either, because the state is not in either list. Remaining inventory could therefore lawfully be sold and installed after the changeover date.

That is the trade’s “sell-through”, and in the 30 unnamed jurisdictions it follows directly from the wording.

Inside the Southeast and Southwest it does not. 10 CFR 430.32(c)(6)(i) attaches to products “installed on or after January 1, 2023”, with no carve-out for the date of manufacture anywhere in the paragraph.

On the face of the text, old stock does not become installable in a regional state merely by having been built early.

The same asymmetry existed in the 2015 generation of the rule, where § 430.32(c)(2) said plainly: “Any outdoor unit model that has a certified combination with a rating below 14 SEER cannot be installed in these States.”

Here is the question the codified text does not answer, and we are not going to pretend otherwise. The regional requirement is expressed in SEER2.

A unit certified only under the superseded appendix M carries a SEER rating and no SEER2 rating at all, so asking whether it "meets 14.3 SEER2" has no answer on the face of the regulation.

How that is resolved in practice is a matter of DOE certification and enforcement guidance rather than of the text quoted on this page, and this page does not cite such guidance because we have not verified it.

Recommendation: a contractor holding pre-2023 inventory destined for a Southeast or Southwest address should get that answer in writing from the manufacturer’s certification, or from DOE, not from an internet summary, including this one.

Does the regional standard apply to heat pumps?

No. 10 CFR 430.32(c)(6)(i) reaches product classes (i) and (iii) of paragraph (c)(5) — split-system air conditioners and single-package air conditioners. Go back to the national table and read what those two classes are: split-system air conditioners, and single-package air conditioners.

The heat pump classes are absent. There is no regional installation standard for a split-system heat pump, a single-package heat pump, or a space-constrained heat pump, in the Southeast or the Southwest or anywhere else.

A split-system heat pump is instead governed only by the national manufacturing standard, which is SEER2 14.3 and HSPF2 7.5 under 10 CFR 430.32(c)(5).

That is a higher cooling number than the 13.4 required of an air conditioner, and the same 14.3 figure that the regional table imposes on air conditioners.

The enforcement machinery reflects this: the 48-month record-retention duty at 10 CFR 429.142(a)(1)(i) is written for “central air conditioner” installations, and the additional single-package record duty at 10 CFR 429.142(a)(1)(ii) applies only in Arizona, California, Nevada, New Mexico.

HYRE analysis: this is the single most consequential misreading of the regional rule, because it runs in the direction that costs homeowners money.

A contractor who believes the Southeast rule applies to heat pumps will quote a higher-tier machine than the law requires, and will be able to point at a real federal regulation while doing it.

The regulation says what it says: air conditioners, two classes, by installation. Whether a heat pump pays on running cost is a separate question, answered by state in the electric vs gas price ratio.

How is the regional standard enforced?

Through record-keeping, notices of violation and sales cut-offs. 10 CFR 429.140 opens a dedicated set of enforcement procedures for exactly these violations. They are short, they are specific, and they are the part of this subject that consumer coverage never opens.

Records: Under 10 CFR 429.142(a)(1)(i), a contractor or dealer installing a central air conditioner in any of 21 named jurisdictions must keep records for at least 48 months from the date of installation.

Those records are the manufacturer name, model number, serial number, full installation address, date of installation and the party the unit was bought from, for the outdoor unit and separately for the indoor unit.

Distributors keep their own records for 54 months and manufacturers for 60. On request from DOE, the records must be produced within 30 calendar days (10 CFR 429.144(b)).

HYRE analysis, and a genuine discrepancy in the text: The 21 jurisdictions in the record-retention paragraph are exactly the Southeast states plus the Southwest states plus the District of Columbia.

They do not include Puerto Rico or the U.S. Territories, which the standard itself names.

We report that as a feature of the codified text we retrieved on September 5, 2026, not as a legal conclusion about what a contractor in San Juan must do.

The efficiency requirement and the record-keeping duty are separate provisions in separate parts of the CFR, and the second is not simply a restatement of the first.

Consequences: 10 CFR 429.146 provides for a Notice of Violation, with an explicit safety valve: “If DOE determines a noncompliant installation occurred in only one instance, the noncompliant installation is remediated prior to DOE issuing a Notice of Violation, and the party has no history of prior violations, DOE will not issue such notice.”

Repeat conduct is treated as a category of its own.

Under 10 CFR 429.148 DOE weighs, among other things: number of violations in current and past cases, length of time over which violations occurred, ratio of compliant to noncompliant installations or sales, percentage of employees committing violations, evidence of intent, evidence of training or education provided, and subsequent remedial actions.

A finding of routine violation carries a commercial sanction, not only a fine.

Under 10 CFR 429.156(a)(1) manufacturers and private labelers must cease selling to that party within 3 business days, and an appeal to the Office of Hearings and Appeals must be lodged within 30 calendar days (10 CFR 429.150(a)).

Civil penalties are separately provided for; this page does not quote an amount, because the figure is inflation-adjusted and we have not retrieved the current one.

What should you do if you live near a region line?

Ask for the certified rating of the exact equipment combination, in writing. The practical effects fall almost entirely on people within an hour’s drive of a regional boundary, and on the contractors who work across it.

Recommendation, for a homeowner: The question to ask is not “what SEER2 do I need” but “what is the certified rating of the specific outdoor-and-indoor combination you are proposing to install at my address.”

The regulation is written against combinations, not against outdoor units: 10 CFR 429.102(c)(4) makes an outdoor unit installed as part of a certified combination rated below the regional standard a violation, and makes an unmatched outdoor unit a violation on its own.

A model number for the condenser alone does not answer the question.

Recommendation, for a border quote: You may be told a cheaper unit is fine because it was bought before the rule changed. In the 21 regional jurisdictions, that does not follow from the text.

The regional paragraph turns on when the unit is installed, not when it was built or bought. Ask for the certified combination rating and the region it complies with, in writing.

What this does not mean: Being in the North is not a reason to buy the minimum.

The regional floor is a legal floor, not an engineering recommendation, and in a hot climate the economics of going above it are usually favorable well before the law requires it.

The efficiency you should buy is a running-cost question, different from the one this page answers; the replacement cost calculator is a place to start.