Frequently asked questions about SRP's residential solar electric program

System design and installation

Prior to installing a solar electric system, please consider the following:

  • Contractor selection. As with any home improvement project, its ultimate success is dependent on choosing the right contractor. Get advice to help you make an educated choice.
  • System Type. There are different types of systems and costs can vary widely among contractors. You should research the system types available so that you ultimately select the best type for your home.
  • Maintenance. Solar electric systems will require ongoing maintenance, so know the system's recommended maintenance schedule and take these costs into consideration when selecting your system type. Some financial options include maintenance costs.
  • Panel location. It is important that the panels receive the greatest amount of sunlight. As a result, you should consider factors that will impact the sun's ability to shine on the panels including shading from obstructions (such as trees), the tilt angle of the panels, and the direction the panels are facing (western exposure is best). Systems with multiple tilts or orientations can hinder production.
  • Mounting. The method of mounting for some systems could impact roof warranties and home insurance policies.
  • Homeowner Association (HOA) rules. Homeowner association rules may affect system selection and mounting, so review your plans with your association before installing a solar electric system.

In February 2003, the Arizona Court of Appeals ruled that a homeowner's prohibition related to the installation of a solar energy system violated the public policy of Arizona as expressed in Arizona Revised Statute Section 33-439. Please refer to this statute to learn more about the state law regarding this issue.

Typically, solar electric systems produce 1,750 kilowatt-hours (kWh) per year per kilowatt (kW) rating of the system. For example, a 5 kW system should produce 8,750 kWh per year. System output will ultimately vary depending on the type of components installed and the system's orientation in relation to the sun.

The typical roof space required for a solar electric system is approximately 100 square feet per kW-DC rating of the system. For example, a 5 kW system will require 500 square feet of unobstructed roof space. The amount of roof space required may vary depending on the type of solar panel installed and its tilt angle. Additionally, new fire code regulations in some jurisdictions require specific easements for safe passage of fire fighters in the event of a fire at the home.

When your home is not being powered by your solar electric system, you will be connected to SRP's electric grid. A new integrated grid is formed by joining your renewable energy with SRP's traditional base load generation. This will ensure a steady, reliable stream of energy to all of SRP's customers.

With proper maintenance, most systems should last at least 20 years. Your contractor should provide you with a comprehensive maintenance plan based on the manufacturer's recommendation for your system type.

Each solar system is unique based on the installation type, configuration, and overall system performance. For solar systems operating in a year with typical weather, the National Renewable Energy Laboratory states there is an average system energy loss of 14%. This is based on factors such as system soiling, shading, wiring, connections, degradation, nameplate rating, age, and system availability.

Typical grid-tied inverter efficiencies exceed 95% under most operating conditions. Efficiency changes as a function of AC output power, DC voltage, and sometimes inverter temperature. More detailed information is available on the California Energy Commission test results page, which includes results for thousands of inverters.

At a minimum, your solar electric system must have the following warranties to qualify for SRP's solar incentive program:

  • Modules. The modules must have a performance warranty from the manufacturer that protects against the electrical output of the unit degrading more than 10% over a 10-year period, and more than 20% over a 20-year period.
  • Inverters. Inverters must have a 10-year warranty provided by the equipment manufacturer that protects against defect or component breakdown.
  • Installation. The installer must provide a 5-year warranty that protects against defects in the overall installation of the solar electric system that degrades the electrical output of the overall system by more than 15%. In addition, the installer must provide a 2-year warranty that covers roof penetration leaks. These installation warranties also must provide for no-cost repair or replacement of affected components, including any associated labor that is not otherwise provided by the manufacturer, during the warranty period.

SRP requires that all customers that will interconnect their solar electric system to SRP's electrical distribution system sign an agreement that outlines the interconnection rules and requirements.

Contractor selection

A properly licensed contractor must install the solar electric system to ensure it complies with all applicable building codes and SRP program requirements. SRP has partnered with a group of preferred residential solar installers. These contractors are licensed, bonded, insured and trained on how solar works in conjunction with our Customer Generation Price Plan.

If you choose to hire your own contractor, here are some helpful tips.

SRP acknowledges that there are two types of contractors that will work on your project – dealers and installers. In some instances, this may be the same company. Both the dealer and the installer must have the appropriate license from the Arizona Registrar of Contractors as outlined below.

The dealer represents the company that has the contract with you for the purchase of the system equipment. Dealers must have one of the following license types: B-, KB-1, KB-2, R-11, CR-11

The installer represents the company that is actually installing the system on your home. Installers must have one of the following license types: R-11, CR-11 or R-39 (for HVAC with solar only).

Please visit the Arizona Registrar of Contractors' website or call them toll free at (888) 271-9286 to verify the validity of the contractor's license.

Small systems

As solar panel prices have fallen and modular solar systems can be found on the shelves in local stores, you may be thinking about installing your own solar system. Before installing any generation sources that will interconnect with SRP's distribution grid, be sure to contact SRP and check the regulations in your local municipality for the proper way to connect. All systems, small or large, go through the SRP application and review process.

Solar systems that are connected to the utility distribution grid have the potential to create electrical backfeed. Electrical backfeed is a term that describes the flow of electricity from a home generation source onto SRP's distribution grid. It can pose a serious safety hazard when there is a power outage at the home. The Underwriters Laboratory (UL) has certified solar equipment to meet stringent safety requirements. All grid-tied solar equipment must have UL certification.

Small, modular solar systems are great for off-grid applications, like on a camper in the forest. However, when it comes to an urban setting, a solar system of any size must have approved equipment and be installed correctly to ensure the safety of everyone. Residents, utility workers, and first responders such as fire fighters need to know that all electrical equipment is safe and to all proper codes.

We look forward to working with you in the solar electric application process, whether you envision a very small system to handle a couple appliances, or a more robust system to power your energy needs. By contacting us, we can work with you to ensure that your home is safe. For more information about how to properly interconnect a solar system call the Residential Solar Team at (602) 236-4448.

Billing and metering

SRP will install a second meter to monitor the energy production from your solar electric system. This information will be available via a report that is included with your monthly bill.

The new Customer Generation Price Plan for Residential Service (E-27) reflects the cost to provide service to customers who choose to generate some of their own electricity through solar or other technologies. This price plan includes a monthly service charge that is composed of distribution charges based on the size of your house (SES size), on-peak grid (kW) charge – also referred to as "demand" – and a lower energy (kWh) charge. Demand is based on the highest amount of power used over a 30-minute on-peak period each month. A special meter will record that information.

Yes, you will still get an electric bill from SRP if your home is attached to SRP's electric grid. You will still be responsible for paying a monthly service charge that covers the costs for billing and collections, meters, competitive customer service, and distribution facilities.

Under the E-27 Customer Generation Price Plan for Residential Service, if the energy produced by the system is greater than the energy you used during the bill-cycle, then the excess energy produced is credited to that month's bill, based on the retail price in the E-27 price plan associated with the time period in which it was generated.

Tax credits

Arizona currently offers a tax credit equivalent to 25% of the system cost, capped at $1,000 per residence, regardless of the number of energy devices installed. The federal tax credit is 30% of the cost. These credits are obtained through your annual tax process. SRP recommends that you contact your tax professional with any further questions on these tax credits and whether you are eligible to take advantage of them.

Back to top