HVAC in Arizona: the Southwest efficiency rule and the running-cost math

Which federal efficiency rule applies in Arizona?

The DOE Southwest rule. Almost every appliance standard binds the manufacturer. This one binds the installation, and it binds it differently in Arizona than in Oregon.

Source fact: 10 CFR § 430.32(c)(6) sets a national minimum for split-system air conditioners of 13.4 SEER2 for equipment manufactured on or after January 1, 2023, and then adds a higher floor in two regions for equipment installed on or after the same date.

Arizona is in the Southwest: “Southwest” includes the States of Arizona, California, Nevada, and New Mexico.

Source fact: In the Southwest a split-system air conditioner under 45,000 Btu/hr must reach 14.3 SEER2, and 45,000 Btu/hr and above must reach 13.8 SEER2 — the same seasonal figures the Southeast carries.

What the Southeast does not carry is the second column. The Southwest alone adds an EER2 requirement of 11.7/9.8 for the smaller class and 11.2/9.8 for the larger, with 10.6 for single-package units.

The regulation defines that measure plainly: “EER refers to the energy efficiency ratio at a standard rating of 95 °F dry bulb outdoor temperature.”

The two-part figure is conditional — “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.”

Source fact: The enforcement sentence is what makes this a homeowner’s problem rather than a manufacturer’s: “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.” It is a restriction on the installation, not on the box.

HYRE HVAC Research Desk analysis: SEER2 is a seasonal average across a synthetic temperature distribution.

EER2 is a single measurement at 95°F. In a state whose largest county averages 3,724 cooling degree days a year, the seasonal average is the less informative of the two, and the federal government has effectively said so by regulating the 95°F number here and nowhere but the four Southwest states.

A unit can carry an impressive SEER2 and a mediocre EER2 — which is exactly the trade the conditional footnote above anticipates, since above 15.2 SEER2 the EER2 requirement drops to 9.8.

The useful next step: Ask for the certified EER2 of the specific matched indoor and outdoor combination, not the outdoor unit, and confirm it is a combination legal to install in the Southwest region. A quote that names only a SEER2 has not answered the question Arizona actually asks.

Is Arizona one climate?

No. The household-weighted state number is the highest in the country. The county numbers include a place that needs more heating than Chicago-adjacent Illinois counties do cooling.

Source fact: In EIA’s Residential Energy Consumption Survey 2020, Arizona’s household-weighted cooling degree days are 4,431 — the highest figure for any state in that file — against 1,396 heating degree days, across 2.68 million households.

Source fact: NOAA’s county normals for 1991–2020 tell a second story. Across Arizona’s 15 counties the cooling figure runs from 4,100 in Yuma County down to 537 in Apache County, a spread of 7.6 times.

Coconino County, which contains Flagstaff, records 5,013 heating degree days against 817 cooling — a heating-dominated county inside the most cooling-dominated state.

HYRE calculation: The county median is 1,625 cooling degree days; the household-weighted state figure is 4,431. The gap between those two numbers is not an error in either: it is Arizona’s population living in Maricopa County and Pima County rather than spread evenly across the map.

A state-average design temperature is therefore the wrong input for anyone in the north of the state, and a Phoenix rule of thumb applied in Flagstaff produces a system sized for the wrong season.

HYRE analysis: This is also why 9.6% of Arizona households (9.6% ± 1.6 percentage points) report using no heating equipment at all, a category most states do not meaningfully have — and why 26.4% already have a heat pump, the 9th highest share of the 32 states the survey can report, against 13.9% nationally.

Is a heat pump cheaper to run than gas in Arizona?

Yes, mostly because gas is expensive here. Source fact: EIA’s 2024 residential averages for Arizona are 14.91 cents per kilowatt-hour and $20.47 per thousand cubic feet of natural gas.

On a common energy basis those are $43.69 and $19.74 per million Btu. Arizona’s electricity price sits 26th of 51 jurisdictions — around the middle. Its gas price sits 5th, near the top.

HYRE calculation: Applying the western census-region heating and cooling averages from RECS 2020 Table CE3.1 to those prices: a 95% gas furnace costs about $476 a year, a heat pump at a seasonal COP of 3.0 about $333, and cooling — which either system pays for — about $306.

The heat pump saves roughly $142 a year on heating.

Source fact: The efficiency at which the two break even in Arizona is a seasonal COP of 2.10 — computed in our electricity-to-gas price ratio study for all 51 jurisdictions. Almost any modern heat pump clears that in this climate.

HYRE analysis: The reason is not that Arizona is hot.

Heat pumps look good here because Arizona pairs mid-table electricity with some of the most expensive residential natural gas in the country, and because the heating season is short enough that heating is the smaller of the two bills anyway — the cooling line above is more than double the heat pump’s heating line.

Arizona ranks 6 of 51 on our Heat Pump Readiness Index for exactly this combination.

Recommendation: Because cooling dominates the bill, the efficiency decision worth paying for in Arizona is the cooling one — the EER2 at 95°F discussed above, and the ductwork that has to carry it. Buying heating capacity you use for 1,396 degree days a year is the wrong place to spend the money.

Who licenses Arizona HVAC contractors, and who sets the code?

Arizona licenses the contractor at state level and leaves the building code to the city. That combination is unusual and it changes what you have to check.

Source fact: HVAC contracting in Arizona is licensed by the Arizona Registrar of Contractors. Our own store holds 799 Arizona contractor records verified against the ROC’s public contractor search on August 16, 2026, of which 799 carry classification CR-39 Air Conditioning and Refrigeration. That is the classification to ask for by name.

Source fact: Arizona’s license threshold is a dollar figure, not a job type. A.R.S. §32-1121 exempts work where “the aggregate contract price, including labor, materials and all other items…is less than $1,000”.

An equipment changeout is not close to that line, so the exemption is irrelevant to the work this page is about — which is precisely why it is worth knowing that it exists and is small.

Source fact: The energy code is not the state’s. The US Department of Energy’s Building Energy Codes Program records Arizona’s residential and commercial energy code status as “None Statewide”, noting it is “Applicable by County or Jurisdiction”.

HYRE analysis: So an Arizona homeowner faces two authorities with no overlap: a state board that decides who may hold the contract, and a city that decides what the installation must meet and what the permit costs.

A contractor licensed statewide is not thereby familiar with your city’s code adoption, and “it meets code” is an incomplete sentence in Arizona until someone names the jurisdiction.

Source fact, with the arithmetic ours: Phoenix charges a valuation-based permit fee rather than a flat mechanical one.

The city’s fee schedule, approved December 17, 2025 and effective January 20, 2026 under Ordinance G-7465, Phoenix City Code chapter 9, appendix A.2, states: “$1,001 - $10,000 — $195 on first $1,000, plus $12 for each additional $1,000, or fraction thereof, to and including $10,000”.

HYRE calculation: on a $8,000 declared valuation that is $195 plus 7 × $12, or $279.

The figure moves with your declared valuation, and other Arizona jurisdictions publish their own schedules — this is Phoenix’s, on the date given, and nobody else’s.

What does our Arizona contractor data cover?

Source fact: HyreHVAC’s contractor store holds 799 Arizona records verified against the Arizona Registrar of Contractors' public contractor search, retrieved August 16, 2026. Every one carries the issuing authority, the register it was checked against and the date it was checked. No Arizona records failed verification.

What that is not: It is not a census of Arizona HVAC contractors, it is not a ranking, and no company has paid for a position in it — we take no payment for placement or a favorable mention.

Arizona is one of eight states where our store rests on a named register; anything on this site that reads as a national claim rests on federal data instead, never on our own counts.

The useful next step: Verify any contractor yourself before signing: the ROC search is public, free and takes about a minute, and it will tell you the classification, the status and the bond.

Our licensing study explains what the eight state registers do and do not prove — including the difference between “we could not verify this” and “this contractor is unlicensed”, which are not the same finding.