Solar panels in Houston

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: October (742 kWh). Weakest: December (561 kWh), a 1.3x difference.
• May, August, October produce 27.1% of the year; February, November, December produce 21.7%.
• Year-to-year variation: about 333 kWh (4.1%, one standard deviation).
• Sunlight reaching the panels: 1,817 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 Texas (ERCOT competitive area)

  Surplus solar is sold to your retail electric provider at an agreed value

  Texas has no statewide net metering rule for competitive areas such as Houston. State law says owners of distributed renewable generation must sell surplus electricity to the retail electric provider serving them, at a value agreed with that provider, which may be a price or a bill credit.

  Source: Texas Legislature, Utilities Code Sec. 39.916, Interconnection of Distributed Renewable Generation (checked 2026-09-25)

• CenterPoint Energy service area

  CenterPoint handles interconnection, not buyback

  CenterPoint Energy approves solar interconnections in the Houston area but does not buy power or offer net metering. Any credit for exported energy comes from a buy-back plan offered by your retail electric provider.

  Source: CenterPoint Energy, Technology and smart meter resources (checked 2026-09-25)

• State of Texas

  Property tax exemption for solar (Tax Code 11.27)

  Texas exempts from property tax the added appraised value of a solar energy device used primarily for on-site energy. Homeowners apply with Form 50-123 at their county appraisal district and do not need to reapply each year once granted.

  Source: Texas Comptroller of Public Accounts, Form 50-123, Exemption Application for Solar or Wind-Powered Energy Devices (checked 2026-09-25)

Houston ranks 4 of 4 for yield among the cities we model in the United States, and 18 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: Rio de Janeiro (1,340 kWh per kWp), Melbourne (1,382 kWh per kWp), Osaka (1,299 kWh per kWp).

Power you use yourself is worth the retail price ($0.154 per kWh in our TX state model); power you export earns $0.05. 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: $15,000 for 6 kWp.
• Incentive modelled: No federal residential capital incentive in 2026 (§25D 30% credit expired 31 Dec 2025, OBBB PL 119-21). State credits (NY 25% cap $5k, AZ 25% cap $1k) modelled in US_STATE_DEFAULTS..
• 25-year net savings at our default: $12,287.

At latitude 29.76°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 0.6% a year over the standard roof in Houston. 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.