How Solar Works With SRP vs APS in the Phoenix Valley

If you live in the Phoenix Valley and you're thinking about solar, the first practical question is which utility you're on: APS or SRP. The answer shapes how much your system saves, how your monthly bill gets calculated, and whether battery storage belongs in your plan from day one.

This isn't a detail you can sort out later. APS and SRP have fundamentally different solar rate structures, and a system that works well on one utility can underperform on the other. Here's what Phoenix Valley homeowners need to know before committing to a system design.

Which Utility Serves Your Home

APS covers most of Phoenix, Scottsdale, Peoria, Surprise, and the northwest valley. SRP serves the east valley, including most of Mesa, Gilbert, and portions of Chandler, Tempe, and east Phoenix. If you're not sure which utility you have, check your electric bill or run your address through our solar calculator.

The boundary between the two utilities isn't always clean. In Chandler and Tempe, adjacent streets can be on different utilities. Don't assume based on your neighbor's experience since the service territory lines don't follow neighborhood boundaries. Confirm your utility before sizing a system.

How APS Treats Solar Customers

APS customers who go solar are moved onto a Time of Use rate plan. The utility credits exported solar power at somewhere between $0.028 and $0.075 per kilowatt-hour depending on time of day. That's considerably less than what APS charges retail, which runs $0.13 to $0.16 per kWh during off-peak hours and higher during the 3 p.m. to 8 p.m. summer peak window.

Solar panels generate their strongest output from roughly 10 a.m. to 2 p.m. That production window falls mostly before APS peak rates begin, which means a portion of your solar output goes back to APS as exported credit at a below-retail rate rather than offsetting expensive peak-hour grid power. This is worth knowing so you can time discretionary loads like the dishwasher or laundry during peak production hours, consuming your own solar instead of exporting it.

For APS customers, solar works well without a battery because daytime self-consumption directly offsets grid purchases. We explain how the export credit calculation works in detail in our post on net metering in Arizona.

How SRP Treats Solar Customers

SRP is structured differently. When you go solar as an SRP customer, you're enrolled in their Customer Generation rate plan, widely known as the E-27 plan. This plan adds a monthly demand charge based on the highest 30-minute period of grid consumption your home records during the billing cycle. It's not just about how much energy you use in total. It's about how hard your home draws from the grid at its peak moment.

SRP currently charges approximately $32.44 per kilowatt of peak demand under E-27. If your home pulls 5 kilowatts from the grid during its highest 30-minute window of the month, that adds roughly $162 in demand charges to your bill before energy usage is even factored in. Solar reduces daytime grid consumption, but if you're drawing significant power on a cloudy afternoon or during the hot evening hours after panels stop producing, the demand charge can erode a meaningful share of your savings.

SRP credits exported solar at a low rate similar to APS. The practical result is that the same system that cuts an APS bill by 90 percent might cut an SRP bill by 50 to 60 percent without storage. That's still real money, but the design conversation is different from the start. For context on how Arizona's summer conditions affect panel output, see our post on solar panel efficiency in Arizona heat.

Phoenix, Scottsdale, and the APS Service Area

For homeowners in central Phoenix, Scottsdale, and the northwest valley, APS is the utility and the solar savings calculation is more predictable. Phoenix averages 6.5 peak sun hours per day annually, one of the highest averages of any major metro in the country. A properly sized system can offset 80 to 100 percent of annual electricity consumption on APS, leaving a household paying little more than the APS monthly service charge of around $15.

Cities like Peoria, Surprise, and Glendale see strong solar results for the same reasons: high summer APS bills and consistent daily sun. A typical 8 to 10 kilowatt residential system in these cities can offset $150 to $250 per month in electricity costs depending on usage. The solar calculator on our site gives you a free estimate based on your address and billing data.

Mesa, Gilbert, and the SRP Service Area

SRP territory covers most of Mesa, the majority of Gilbert, and a significant portion of east Chandler. For homeowners in these cities, going solar takes more planning than it does on APS, but the case is still solid. The demand charge on E-27 responds to how your home draws power from the grid at its peak moment, not just total monthly consumption, so the strategy is about managing those peak draw windows.

Even on SRP, daytime self-consumption directly reduces energy charges. Homes with consistent daytime electricity use, such as a home office, pool equipment running mid-morning, or appliances scheduled during daylight hours, still see real reductions. System performance data from east valley installations consistently shows 40 to 70 percent reductions in annual electricity costs for well-designed SRP solar setups.

Adding battery storage to a solar system in SRP territory changes the math considerably. A battery stores excess daytime solar production and discharges it during the evening hours when the panels stop producing. That reduces the grid draw during the window that typically registers the highest demand reading, which can cut or eliminate the demand charge entirely in many months. If you're in Mesa, Gilbert, or east Chandler, discussing storage before finalizing your system design is time well spent.

The Prepaid Lease Advantage on Both Utilities

Phoenix Valley Solar offers a prepaid solar lease that reduces the total system cost by 30 percent upfront. You pay once at a discounted rate, own the production your panels generate, and carry no monthly loan payment. The 30 percent savings applies whether you're on APS or SRP.

For APS customers, that discount accelerates an already solid return on investment. For SRP customers, we work through your utility bill history with you, determine whether storage makes sense based on your usage patterns, and design a system built around E-27 rather than just kilowatt-hour offset. Visit our about page to learn how Phoenix Valley Solar works with homeowners across both utilities, or contact us to start with a free bill review.

Frequently Asked Questions

Does solar work differently depending on whether I have APS or SRP?

Yes. APS uses a Time of Use net billing structure without a demand charge. SRP uses the E-27 plan that bills based on the highest 30-minute grid draw each month. That difference affects system design, expected savings, and whether battery storage belongs in your plan.

Which utility gives you better solar savings, APS or SRP?

APS typically allows solar to offset a higher percentage of the monthly bill because the rate structure is simpler and doesn't include a demand charge. SRP requires more planning but still produces meaningful savings with the right system design.

Can I still save money going solar if I'm on SRP?

Yes. Daytime self-consumption reduces energy charges on SRP regardless of the demand plan. East valley homeowners on SRP who size their systems around their actual usage patterns consistently see 40 to 70 percent reductions in annual electricity costs.

What is the SRP E-27 plan and how does it affect solar savings?

E-27 is SRP's rate plan for solar customers. It charges approximately $32.44 per kilowatt of peak demand per month, measured from the highest 30-minute grid draw during the billing period. Solar reduces energy charges but doesn't automatically eliminate the demand charge, which is why battery storage can make a significant financial difference for SRP solar customers.

How do I find out if I'm on APS or SRP?

Your electric bill shows the utility name clearly. You can also run your address through our solar calculator, and we'll confirm your utility as part of the free analysis.