How Stand-Alone Batteries Help Phoenix Homeowners Beat Peak Electricity Rates

Phoenix homeowners are facing a new energy reality. Electricity costs continue to rise, driven by more frequent rate increases and a concerted shift toward time-of-use pricing that pushes the most expensive on-peak hours later in the day. As a result, more Arizona residents are looking for ways to reduce their dependence on inflating utility costs. One of the most effective solutions available in today’s more complex utility environment is a home battery system.

Key Takeaways:

• Stand-alone batteries—without solar—are becoming a smart entry point for homeowners looking to save money and gain outage protection with a lower upfront cost. Solar can always be added later to expand savings and resilience.
• Electricity rates in Arizona continue to rise, with the biggest impact felt during late-afternoon and evening on-peak hours, when electricity is most expensive and solar panels are less effective. Batteries help homeowners store low-cost energy and use it when rates are highest.
• Battery-only systems do not require solar panels and still provide meaningful savings by avoiding expensive on-peak pricing and peak demand charges.
• Adding a battery ensures your home—and critical systems like air conditioning or medical devices—remain powered, even during grid outages.
• Batteries protect homeowners from future utility rate increases by reducing dependence on peak grid power.
• Adding solar panels later can significantly boost savings, but panels are not required to start benefiting from batteries.

At Sun Valley Solar Solutions, we no longer view batteries as simple “bolt-on” to a solar project or just for backup during outages. Batteries are powerful financial tools that help homeowners reduce exposure to rising utility rates, avoid costly on-peak pricing, provide security in the event of a grid outage. This used to be the primary mission of solar panels - and it still is - but as utilities shift their most expensive hours later in the day when solar panels are less effective, batteries are now the central technology for moving away from utility dependence. 

With that said, this blog will attempt to explain how on-peak pricing has changed, why they’re utility pricing is poised to continue climbing across Arizona, and how stand-alone batteries can offset these costs—while leaving the door open to add solar later to further amplify long-term savings.

Understanding Peak Electricity Rates in Arizona

Most Arizona utilities use time-of-use (TOU) rate structures. Under these plans, electricity costs vary depending on the time of day. Peak hours are typically when energy demand is highest, often in the late afternoon and early evening during the hottest months of the year.

In Phoenix, this timing is especially painful. Peak hours –when utility rates are most expensive–typically occur later in the day, and often coincide with:

• Maximum air conditioning use
• Reduced solar production from rooftop systems 
• Families returning home from work and turning on appliances to gain relief and comfort

During these on-peak windows, electricity costs significantly more per kilowatt-hour than during off-peak times, such as overnight or midday. What’s more, older rate plans that placed the most expensive on-peak hours in the mid afternoons are now being replaced by plans that place on-peak hours much later in the day when solar panels alone are far less effective. 

APS and SRP Peak Rates (High-Level Overview)

APS time-of-use plans concentrate peak pricing in the late afternoon and early evening on weekdays, most commonly 4:00 PM to 7:00 PM, when grid demand is highest and solar production is naturally trailing off. Over the past several years, APS has continued to widen the gap between on-peak and off-peak pricing—making electricity used during these high demand hours significantly more expensive than power consumed earlier in the day or overnight.

SRP also relies on time-based pricing, with on-peak windows generally occurring in the late afternoon between 2:00 PM. and 8:00 PM. on weekdays, or shifting to a split schedule in the winter months that places on-peak hours from 5:00 AM to 9:00 AM and again from 5:00 PM to 9:00 PM.

In addition to time-of-use rates, many APS and SRP plans include demand charges, which are based on the single highest burst of electricity usage during the month—often driven by air conditioning cycling on during hot afternoons. This means even short spikes in usage during peak hours can disproportionately impact a homeowner’s bill.

While the exact peak pricing windows and rate structures vary by plan, the broader trend is unmistakable: electricity used during late-day is becoming increasingly more expensive, and utilities are incentivizing customers to shift—or reduce—consumption during those times to reduce burden on the electrical grid. This changing landscape is a major driver behind the growing interest in home battery systems, which allow homeowners to store lower-cost energy and use it precisely when peak rates hit.

Are Utility Rates Increasing in Arizona?

Yes—Arizona utility rates have been steadily increasing for years, and most projections indicate this trend will continue. After a 4% across-the-board rate increase in 2024, APS has since filed a request with the Arizona Corporation Commission seeking an additional 14% increase in Fall 2026. Similarly, in November 2025, SRP rolled out new rate plans that not only shift on-peak hours later into the evening—5–9 PM and 6–10 PM, depending on the plan—but also include an average rate increase of approximately 3.5% for most SRP customers across the board.

Several factors are driving these regular increases:

• Rising demand from population growth and commercial development (data centers)
• Hotter and longer summers driven largely by climate change impact
• General grid modernization and infrastructure upgrades

Utilities are placing more of the cost burden on when electricity is used rather than just how much is consumed. For homeowners who rely entirely on the grid during peak hours, this often results in higher and more unpredictable monthly bills.

Read More: SRP’s New Rate Plans: What Solar Customers Need to Know

What Is a Stand-Alone Battery System?

A stand-alone battery stores low-cost grid electricity so it can be used later. In simple terms, you charge up when power is cheap and discharge when it’s most expensive—effectively taking your home off-grid during peak hours to avoid the highest daily utility rates.

The process is largely seamless. Once charged, the battery automatically activates during peak pricing periods, with no dimming lights or momentary outages to contend with. From the homeowner’s perspective, it’s quiet, automatic, and virtually invisible.

This strategy—often called load shifting or peak shaving—is one of the most effective ways Phoenix homeowners can protect themselves from rising utility rates. By avoiding the most expensive hours of the day and relying on stored energy instead, homeowners can significantly reduce costs. Depending on your rate plan, the battery may even charge during ultra-low super off-peak hours, typically overnight, when electricity is at its cheapest. The system is programmed to align charging and discharging automatically with your specific utility rate structure.

How Stand-Alone Batteries Beat Peak Rates

1. Offset the Most Expensive Electricity: Instead of paying premium prices during costly on-peak hours, your home runs entirely on stored energy during that timeframe. This essentially eliminate the most expensive portion of your electric bill.
2. Store Cheaper Off-Peak Power: Batteries can be programmed to charge when electricity is cheapest - often overnight. This allows homeowners to take advantage of lower overnight or midday rates and avoid on-peak pricing altogether.
3. Reduce Exposure to Future Rate Increases: As utilities continue raising peak rates over time, battery owners are less affected because they rely less on grid power during those high-demand, high-cost windows of time. The only power you need to purchase is the cheapest power.
4. Batteries don’t care if the sun is shining: Because stand-alone battery systems can charge from the grid, they don’t rely on sunshine to operate. They can charge overnight or on cloudy days—anytime electricity is cheapest—and discharge during peak pricing periods, helping reduce energy costs regardless of whether the sun is out.
5. Start with a battery, add solar later: Solar panels remain an important tool for offsetting daytime energy use and for providing a reliable charging source in the event of a grid outage. That said, solar doesn’t have to be installed on day one to realize a savings benefit. A stand-alone battery can serve as a smart starting point—delivering immediate savings and resilience, with the flexibility to add solar later as your energy needs and goals evolve.

Typical Battery-Focused Configurations

Sun Valley Solar designs battery systems around comfort, savings, and security. Systems are available with or without solar panels, allowing homeowners to start where it makes the most sense financially and expand later if desired.

Most battery or battery + solar system designs fall into one of three categories. Let’s take a quick look at these common approaches. 

• Bill Shaver - Focused on savings without blackout protection

This approach is designed specifically to offset the utility’s most expensive electricity but is not configured to provide backup power during outages.

Key benefits

• • Targets high on-peak electricity rates only
  • Stores energy when prices are lowest and discharges it when prices are highest
  • Does not operate during grid outages
  • The most cost effective option. 

This is often the most cost-effective option for homeowners primarily focused on lowering monthly utility bills and beating peak rates, without a need for blackout protection.

• Essential loads – savings plus critical loads backup

The essential loads approach builds on the bill shaver strategy while adding peace of mind during outages for a select group of critical electrical circuits, but not the whole house. .

Key benefits

• Includes all peak-shaving and bill-saving benefits
• Provides backup power for selected critical circuits 
• Common backed-up loads include:
  • Lights
  • Refrigerator
  • WiFi and internet equipment
  • Medical devices
  • Garage door
  • Select outlets or rooms

This option is ideal for homeowners who want both financial savings and limited outage protection without having to invest in a large enough battery to power the entire home.

• Whole home backup – maximum control and energy resilience

For homeowners seeking the highest level of energy independence, a whole-home backup system provides complete coverage for all electrical circuits in the home. These systems typically require multiple batteries to deliver the capacity needed to power a full Arizona household.

Key benefits

• • All the bill shaving benefits of the other two packages
  • Fully customized maximum-capacity battery design
  • Supports whole-home backup during outages
  • Maximizes long-term savings and energy resilience and flexibility

While this is the most comprehensive option, it also delivers the greatest control over energy costs and long-term resilience

Read More: An Easy Guide to Choosing the Right Battery for your Arizona Home

Solar Panels Are Still Wise Addition

Stand-alone batteries can offer a lower-cost entry point into energy savings and resilience without requiring an immediate investment in solar panels. Battery-only systems recharge from the grid when electricity rates are lowest and then discharge during the most expensive on-peak hours—effectively taking your home off-grid when energy costs are at their highest.

That said, solar panels are strongly recommended. Solar reduces the need to purchase daytime grid power altogether and, more importantly, provides a reliable way to recharge your battery during extended grid outages. When the grid goes down, your battery will automatically power your home, but once depleted—often within a few hours, depending on capacity—the home will remain without power until grid service is restored.

By adding solar, you gain the ability to continuously recharge your battery and keep your home powered if the outage lasts longer than a few hours. This is particularly important during our hottest summer months here in Arizona, when having a functional AC can be a matter of life and death. When combined together, solar and battery storage turn your home into its own power plant. With sufficient capacity, some homeowners can dramatically reduce—or even eliminate—their reliance on grid electricity altogether.

Take Control and Start Saving

In Phoenix, beating peak rates isn’t about using less electricity. It’s about using electricity smarter.

Stand-alone batteries give homeowners a powerful new level of control by shifting energy use away from the most expensive hours of the day. Instead of reacting to rising utility rates, you can proactively manage when and how your home draws power—on your terms, not the utility’s.

With a properly designed battery system, Arizona homeowners can:

• Avoid the most expensive on-peak electricity
• Reduce exposure to future rate increases
• Add resilience and limited backup power
• Gain flexibility without committing to solar right away
• Build a system that can expand over time as needs grow

Whether your goal is strictly bill savings, protection from short outages, or a long-term path toward full energy independence, there’s no one-size-fits-all solution. That’s why Sun Valley Solar designs battery systems around your home, your rate plan, and your goals—backed by local expertise and decades of Arizona experience.

Peak rates may continue to rise, but with the right battery strategy, your energy costs—and your peace of mind—don’t have to rise with them. If you’re ready to find out how much you could save, schedule a complimentary battery and rate-plan review with our local energy experts.