Is a mini split worth it in Arizona?
Short answer: Yes, for most Arizona homes. Phoenix logs about 2,141 cooling hours and 1,116 heating hours a year (ENERGY STAR), so it works as the air conditioner first and the heater on winter nights. Every MRCOOL DIY series keeps heating below Arizona’s coldest night of the last ten winters, −9°F in Flagstaff. Power costs 15.1¢ per kWh; for the lowest bill, pick DIY 5th Gen. Size each room with the standard chart and go one size up for west-facing or top-floor rooms.
Arizona by region
Arizona has three kinds of weather for a mini split. The table shows the numbers HVAC sizing uses for each region.
| Region (climate zone) | Summer high | Winter low | Coldest, last 10 winters | Main job |
|---|---|---|---|---|
| Phoenix (2B) | 108.5°F | 39.3°F | 30°F | Cooling first |
| Tucson (2B) | 103.6°F | 32°F | 24°F | Heating and cooling |
| Yuma (2B) | 108.9°F | 42.3°F | – | Cooling first |
| Prescott (4B) | 92.4°F | 18.2°F | 5°F | Heating and cooling |
| Flagstaff (5B) | 83.6°F | 4.4°F | −9°F | Heating first |
Design temperatures: ASHRAE 2021 climatic design conditions (1% cooling, 99.6% heating dry bulb) for each airport station. Climate zones: 2021 IECC by county (PNNL guide). Coldest: NOAA station records, December 2016 to February 2026.
Cooling through Arizona summers
Yuma designs for 108.9°F in summer, and Phoenix logs 2,141 cooling hours a year (ENERGY STAR). The inverter slows down instead of switching off, so it holds the temperature on long afternoons with less power.
Will it heat in a Arizona winter?
Yes. Arizona’s coldest night at these stations in the last ten winters was −9°F in Flagstaff, and the MRCOOL DIY series heat down to −12°F and −13°F.
What size for a Arizona room
Measure each room (length × width) and match it to an indoor unit.
| Room size | Indoor unit | Single zone voltage |
|---|---|---|
| Up to 250 sq ft | 6K BTU (multi-zone only) | – |
| 251–400 sq ft | 9K BTU | 115V |
| 401–550 sq ft | 12K BTU | 115V |
| 551–800 sq ft | 18K BTU | 230V |
| 801–1,050 sq ft | 24K BTU | 230V |
| 1,051–1,550 sq ft | 36K BTU | 230V |
Go one size up for rooms with west or south windows, a top floor under the roof, high ceilings, poor insulation, or a kitchen. A garage that isn’t insulated also goes one size up. Full sizing guide
Several rooms? See multi-zone systems
What it costs to run in Arizona
Yearly cost to heat and cool one room with Phoenix weather, at the Arizona average power price.
| Size | DIY Select | DIY EasyPro | DIY 5th Gen |
|---|---|---|---|
| 9K | $337 | $326 | $269 |
| 12K | $445 | $415 | $362 |
| 18K | $672 | $630 | $521 |
| 24K | $915 | $892 | $765 |
| 36K | – | – | $1,356 |
Estimate, not a quote: (cooling BTU × 2,141 cooling hours ÷ SEER2 + heating BTU × 1,116 heating hours ÷ HSPF2) ÷ 1,000 × 15.05¢. Hours: ENERGY STAR heat pump savings calculator (Phoenix). HSPF2 is the standard rating (Region IV) shown on the product pages. Other cities: Tucson 1,842 cooling and 1,261 heating hours, Yuma 2,315 cooling and 907 heating hours, Flagstaff 179 cooling and 2,854 heating hours. Power price: EIA, August 2026.
What the equipment costs
Prices for complete single zone systems: outdoor unit, indoor unit, pre-charged line set and remote. Shipping is free to Arizona.
| Size | DIY Select | DIY EasyPro | DIY 5th Gen |
|---|---|---|---|
| 9K | $1,249 | $1,487 | $2,329 |
| 12K | $1,399 | $1,599 | $2,359 |
| 18K | $1,690 | $1,806 | $2,909 |
| 24K | $1,899 | $2,109 | $3,329 |
| 36K | – | – | $3,769 |
Rebates in Arizona
MRCOOL’s rebate data lists 2 utilities in Arizona with rebates on our DIY models, and all of them need a participating contractor, so a DIY install usually doesn’t qualify. The federal 25C tax credit ended for systems installed after December 31, 2025.
| Utility | Up to | Who installs | Series |
|---|---|---|---|
| City of Flagstaff (income-qualified) | $2,000 | Needs a participating contractor | DIY 5th Gen, DIY EasyPro, DIY Select |
| Salt River Project (SRP) | $881 | Needs a participating contractor | DIY 5th Gen, DIY EasyPro, DIY Select |
Rebates checked November 2026. Amounts change; confirm with your utility.
DIY or a pro
MRCOOL DIY systems are built for a homeowner install: the line set comes pre-charged and connects by hand, so there’s no vacuum pump or refrigerant work. Most people hire an electrician for the new circuit, and permit rules depend on your city. Can you install a mini split yourself?
Which MRCOOL system for Arizona
Mini split questions for Arizona
Is a mini split worth it in Arizona?
For most homes, yes. It cools through Arizona summers and heats through the winter, so one system covers the whole year.
Will it keep up in a Arizona summer?
DIY EasyPro and DIY 5th Gen are rated by MRCOOL to cool with outdoor temperatures up to 122°F. Yuma designs for 108.9°F.
Does it heat in a Arizona winter?
Yes. DIY Select heats down to −12°F outside and DIY EasyPro and DIY 5th Gen down to −13°F. Arizona’s coldest night in the last ten winters was −9°F in Flagstaff.
How much does it cost to run in Arizona?
For a 12K room with Phoenix weather at 15.05¢ per kWh, about $445 a year with DIY Select, $415 with DIY EasyPro and $362 with DIY 5th Gen, heating and cooling together. Estimates, not quotes.
What size do I need for a Arizona garage?
Use the same chart: measure length × width. A garage that isn’t insulated goes one size up.
Are there mini split rebates in Arizona?
Some utilities list rebates for MRCOOL DIY models; see the table above. Check each program’s rules: many need a participating contractor. The federal 25C tax credit ended for systems installed after December 31, 2025.
Can I install it myself?
Yes. The pre-charged line set connects by hand, with no vacuum pump. Most people hire an electrician for the circuit, and permit rules depend on your city.
How long does shipping to Arizona take?
Verified orders ship from Kentucky in 2 to 4 business days, then 3 to 7 by freight. Shipping is free to Arizona.