The rooftop replacement, step by step
Central Phoenix, Tempe, Glendale and older Mesa run packaged units on the roof — one cabinet holding the compressor, coils, blower and often a gas burner section. Replacing one is a different job from a ground-level split, and the quote should show it:
- Curb and roof inspectionThe new unit sits on the old curb or an adapter curb. A cracked or rotted curb, or a foam roof due for recoat, gets found now or leaks later.
- Crane schedulingA crane day is $300–$800 of the quote and is booked a week out. Two or three units on the same street the same morning is how installers keep it cheap — ask.
- Electrical and gasDisconnect, whip and breaker sized to the new unit's rating plate; on gas/electric units, the gas line and flue are re-connected and leak-tested.
- Set, seal, duct-connectUnit set on the curb, curb seal, supply and return plenum connections sealed with mastic. Leaking plenums on the roof are the source of a lot of Valley "weak cooling."
- Commissioning at altitude and heatCharge by subcooling, airflow verified, static pressure recorded. A unit commissioned in April will be running at 118°F condenser inlet in July; the installer should set it for that.
- Ground split alternativeSome rooftop homes convert to a split with the condenser on a slab and an air handler in the attic. It costs more up front and is quieter and easier to service; it is worth a quote.
SRP Cool Cash: what it pays per ton
Salt River Project serves roughly half the Valley — much of Mesa, Chandler, Gilbert, Tempe and parts of Phoenix. Its Cool Cash rebate is paid on a new central AC, heat pump or mini-split at 15.2 SEER2 or better installed by a participating contractor, and it scales with the compressor type and the tonnage. Up to $1,125 total. The published tiers:
| Compressor type | Per ton | 3-ton example | 5-ton example |
|---|---|---|---|
| Single-stage, 15.2 SEER2+ | $75 | $225–$240 | $375–$400 |
| Multi-stage, 17.0 SEER2+ | $150 | $450 | $750 |
| Variable-capacity, 20.0 SEER2+ | higher tier | $550 range | up to $1,125 |
| Inverter mini-split | by half-ton | Ducted or ductless, paid on nominal capacity | |
SRP also pays 75% of duct testing and repair up to $400 — worth adding to any replacement on an older duct system — and up to $100 plus $25 a year for a smart thermostat. Current tables and the participating-contractor search are on the SRP residential rebates site. If your bill says APS instead, the picture is different: APS offers thermostat rebates through Cool Rewards and its marketplace, and we have not found a current APS residential HVAC equipment rebate to point you to — check APS directly. The federal 25C credit ended for equipment placed in service after 2025.
Equipment that survives Phoenix
Phoenix logs about 3,960 cooling degree days a year in a dry climate (zone 2B). Latent load is minor; sensible load is enormous, and the condenser works in air that can exceed 115°F. What that argues for:
- Variable-speed or two-stage
- The rebate is bigger and so is the bill saving; a unit that runs at 60% for twelve hours beats one that slams on and off at 100%.
- High-ambient rating
- Ask what the unit is rated to run at. Some inverter systems derate or lock out above 115°F; some are rated to 125°F. In Phoenix that is not a footnote.
- Heat pump over furnace
- About 1,200 heating degree days a year. A heat pump does the winter on its own nearly every night; a gas furnace in a Valley house runs a few weeks.
- Shade and placement
- A ground condenser on the north or east side, or under a shade structure, runs cooler than one on the west wall. It costs a longer line set and is worth it.
What fails on a bad install here
The failures we see on two-year-old Valley systems come from the install, not the equipment: an overcharged system that was set up in March and never rechecked; a rooftop curb that was not resealed; ducts in a 140°F attic left at R-4; a 5-ton unit on a 3.5-ton house because "it gets hot." The installer who does a load calculation and commissions by the numbers is the one to pay.
Where in the Valley
Installers cover the City of Phoenix and the Maricopa County cities around it: Mesa, Chandler and Gilbert in the East Valley; Tempe and Scottsdale; Glendale, Peoria, Surprise, Goodyear and Avondale in the West Valley, plus Ahwatukee, Arcadia and the north Phoenix corridor. The replacement wave is in two places: 1980s rooftop packaged units in central Phoenix, Tempe, Glendale and older Mesa that are on their third compressor, and the first generation of 1998–2006 split heat pumps in Gilbert, Chandler, Surprise and Goodyear reaching twenty years.
Phoenix permits: the like-for-like exemption
Phoenix is the one metro where a straight replacement usually needs no permit. The City of Phoenix Planning and Development Department exempts air conditioner replacements that do not increase size or capacity and do not change location. That covers a same-tonnage swap on the same curb or slab. Upsizing, converting a rooftop unit to a split, moving the condenser, or adding an electrical circuit brings the job under permit and inspection. The department's work-exempt-from-permit document is the authority: Phoenix Planning and Development. Mesa, Chandler, Gilbert, Scottsdale and Glendale each apply their own rules.
Exempt from permit is not exempt from licensing. The installer must hold an Arizona Registrar of Contractors license, and the SRP rebate application requires the ROC number. Every installer in this network has one.
Installed costs in Phoenix
Mid-range labor; the crane and roof work put rooftop replacements above the equivalent ground split. Typical, permitted where required, before SRP rebates:
- $5,500–$16,500Rooftop packaged heat pump or AC, 3–5 tons, including crane
- $6,500–$18,500Rooftop gas/electric packaged unit
- $5,000–$17,000Split heat pump, condenser + air handler
- $4,500–$14,500Split central AC only, condenser + coil
- $3,000–$5,000Mini-split, per zone
- $300–$800Crane day, when not bundled
- $1,500–$6,500Duct sealing or replacement, attic system, before the SRP duct rebate
If a repair quote brought you here — a compressor on a rooftop unit past ten years, usually — the Phoenix AC repair page has the numbers to put against these. The repair-or-replace calculator for any metro is on the installation page.