Solar panels in Phoenix

Modelled output of a 6 kWp system at 35° facing south (towards the equator), from PVGIS climate data (PVGIS-ERA5, 2005 to 2023).

• Best month: March (983 kWh). Weakest: December (759 kWh), a 1.3x difference.
• March, April, May produce 27.9% of the year; July, November, December produce 23%.
• Year-to-year variation: about 171 kWh (1.6%, one standard deviation).
• Sunlight reaching the panels: 2,461 kWh per m² a year.

Rules set by the city or its region, on top of the national scheme. Each one was checked against the official source on the date shown.

• State of Arizona

  Arizona solar energy device credit

  Arizona residents can claim a state income tax credit of 25% of the cost of a solar energy device installed at their Arizona residence, capped at $1,000. Unused credit can be carried forward for up to five years.

  Source: Arizona State Legislature, A.R.S. 43-1083, Credit for solar energy devices (checked 2026-09-25)

• State of Arizona

  Solar adds no value for property tax

  Under Arizona law, rooftop solar and other systems producing energy primarily for on-site use are treated as adding no value to the property for property tax assessment.

  Source: Arizona State Legislature, A.R.S. 42-11054 (checked 2026-09-25)

• APS service area

  APS export credit (Resource Comparison Proxy)

  APS credits exported solar energy at the Resource Comparison Proxy rate. The tranche for 1 September 2026 to 31 August 2027 is $0.05554 per kWh (2025 tranche: $0.06171), and a customer's initial rate is locked for 10 years from interconnection.

  Source: Arizona Public Service, Rate Rider RCP (Effective September 1, 2026, Decision No. 82122) (checked 2026-09-25)

• SRP service area

  SRP Time-of-Use Export Price Plan credit

  SRP customers on its Time-of-Use Export Price Plan (E-13) are credited $0.0345 per exported kWh, per the ratebook effective from the November 2025 billing cycle. SRP states the plan and credit rate are subject to change.

  Source: Salt River Project, SRP Standard Electric Price Plans, E-13 (Effective November 2025 Billing Cycle) (checked 2026-09-25)

Phoenix ranks 1 of 4 for yield among the cities we model in the United States, and 1 of 41 across every country on Solar Figures. Within one country the prices are the same, so a payback gap between these cities comes from sunshine alone (US cities use their own state's prices).

Closest yield abroad: Perth (1,618 kWh per kWp), Seville (1,597 kWh per kWp), Valencia (1,563 kWh per kWp).

Power you use yourself is worth the retail price ($0.16 per kWh in our AZ state model); power you export earns $0.035. So the share you use at home, by running appliances in daylight or adding a battery, changes the payback. The system cost stays the same in every row (a battery would add to it).

• Net system cost after incentives: $14,000 for 6 kWp.
• Incentive modelled: $1,000 (AZ 25% state credit (cap $1,000)).
• 25-year net savings at our default: $15,595.

At latitude 33.45°N, PVGIS finds the fixed tilt and direction that maximise yearly output. Our figures use a common 35° roof; the table shows what the optimum adds.

The optimum adds 0.1% a year over the standard roof in Phoenix. Most of a roof's value comes from its direction: a roof facing away from the equator loses far more than a few degrees of tilt.