Solar vs. HVAC in Arizona: Which Should Come First?

Solar vs. HVAC in Arizona: which should you do first? It's 112 degrees, the AC has run all day, and the bill is painful. The solar company says to install panels. The HVAC company says to replace the AC. Both might be right, but the order matters.

In Arizona, the answer depends on four things. How much power does the house use? When does it use it? Which Arizona Public Service (APS) or Salt River Project (SRP) rate plan are you on? And what is exported solar actually worth? HVAC and insulation fix how much power you need. A better rate plan fixes when you use it. Solar makes power, and a battery shifts it to later hours. Fix the first two, and you avoid buying solar that's too big or poorly timed.

Solar vs. HVAC in Arizona: The Short Answer

HVAC first usually makes more sense when:

The AC is 10–15+ years old or needs frequent repairs
It runs nearly nonstop and can't hold the thermostat setting
Summer usage keeps climbing
Airflow is weak or the ducts leak
Attic insulation is poor
The home has more than one aging AC unit

Solar first may make more sense when:

The HVAC is modern and efficient, and the house holds temperature well
Annual usage is stable and the roof gets strong sun
The home uses a lot of power during daylight hours
You plan to stay long term

A battery may move ahead of more solar when:

Existing solar exports a lot of power for very little credit
Much of your use falls in expensive evening peak hours
Demand charges are a big part of the bill
Outage protection matters to you

AC Uses Power. Solar Makes It.

An air conditioner uses electricity. Solar panels make it. That simple difference is the key to the whole decision. HVAC changes how much power the home needs. In Arizona, cooling can dominate the bill for months. An inefficient AC raises your kWh (kilowatt-hours, the unit on your bill), your peak demand and the size of any solar system, all at once.

Solar changes where some of your power comes from. It doesn't fix an old compressor, leaky ducts, poor insulation or a system that's the wrong size. If the house is wasting energy, solar can become an expensive way to cover the waste.

How HVAC First Can Shrink the Solar System

Suppose a Phoenix-area home uses 28,000 kWh a year, and a solar proposal is sized around that. But the house has two aging AC systems, weak insulation and leaky attic ducts. After HVAC and insulation upgrades, usage falls to 21,000 kWh. That's 7,000 fewer kWh a year for solar to cover.

In Arizona sun, 7,000 kWh a year is about what a 4 kW solar system makes. That's roughly $10,000 to $15,000 of equipment you may not need. It also means less to finance and less power sent to the grid at low credit rates. So ask yourself: would you rather pay for panels to make those 7,000 kWh every year, or stop needing them?

If an old AC is driving the bill, the answer shouldn't automatically be more panels. Sometimes you need fewer kilowatt-hours.

APS Customers: Compare Rate Plans First

APS offers four main residential plans. There's a fixed-price plan and a time-of-use (TOU) plan, where the price depends on the time of day. There's also a TOU plan with a demand charge and an EV plan with cheap overnight hours.

APS has an online plan comparison tool that uses your own past usage. Run it before you buy anything. A better-matched plan can save money with no new equipment.

The 4–7 p.m. Problem

On APS TOU plans, on-peak hours are 4–7 p.m. on weekdays, all year. That's a tough window for solar. Rooftop output is fading just as the AC, stove, dryer, pool pump and EV charger may all be running. SRP's time-of-use peaks run later: 6–9 p.m. on its Conserve plan and 5–10 p.m. on its Manage Demand plan.

Arizona does have one built-in advantage. Solar output is strong when cooling demand is high, so much of your solar can be used right in the home. The gap comes in the late afternoon and evening, when panels slow down but the AC keeps working.

West-facing panels, pre-cooling, shifting loads and batteries can help close that gap. That's why solar design should use hourly usage, not just yearly kWh.

Demand Charges Can Make One Hour Expensive

On APS's TOU with Demand Charge plan, part of your bill is a demand charge. That's a fee based on your highest one-hour use during on-peak hours that month. Picture 5:30 p.m. with two ACs, the oven, the dryer and an EV charger all running.

Your monthly kWh might look fine, but that one hour can still cost you. Sometimes the first move is just spreading those loads out.

Pre-Cooling Works Best in a Tight House

Pre-cooling shifts AC work into cheaper hours. A common approach is to cool the home about 3 degrees below normal before peak, then set it 2 to 3 degrees warmer during peak. The house itself stores the coolness.

That only works if the building envelope (the roof, walls, windows and insulation) holds the cool air in. Thin attic insulation, air leaks and leaky ducts make the AC work harder and push solar and battery sizes up. Fixing them improves your HVAC, your rate plan and any solar at the same time.

SRP Customers: Know Your Solar Plan Before Sizing

“SRP solar” isn't one product. The math varies a lot from plan to plan. An export credit is what the utility pays for extra solar you send to the grid. On the Time-of-Use Export and EV Export plans, it's a flat 3.45¢ per kWh.

Solar customers on the Conserve or Manage Demand plans earn even less: 1.87¢ per kWh for exports, starting with the May 2026 billing cycle. SRP recalculates that rate every May.

APS Solar Uses RCP Net Billing

New APS solar customers don't get old-style net metering, where exports offset power at the full retail price. They're on the Resource Comparison Proxy (RCP), a net-billing plan that pays a monthly dollar credit for exports. For systems connected from September 1, 2026, the RCP rate is 5.554¢ per kWh, locked for 10 years.

Why Low Export Credits Change Solar Sizing

With either utility, solar you use at home is usually worth more than solar you export. Say your panels make extra power at noon. If the home uses it, you avoid buying that power. If you export it at 1.87¢, you get very little. So a smaller system the home uses directly can beat a larger one that exports heavily.

This is where HVAC gets interesting. A new AC uses less power, so less of your solar gets used at home. That's fine as long as you also skip the panels you no longer need. The goal isn't to use the highest share of your solar. It's to lower your total home-energy cost.

Compare the Extra HVAC Cost, Not the Full Price

If the AC needs replacing anyway, don't compare the full price of a new system against solar. In a hypothetical example, a standard system costs $11,000 and a high-efficiency variable-speed system costs $16,000. Your real efficiency decision is the $5,000 difference. Comparing $16,000 of HVAC against $0 makes no sense when a replacement is coming either way.

Then subtract any rebate you actually qualify for. SRP offers up to $1,125 on qualifying AC systems rated SEER2 15.2 or higher (SEER2 is a cooling efficiency rating). The amount depends on system type and size. SRP also offers up to $600 for attic insulation and up to $400 for duct testing and repair.

Hold Solar to the Same Standard

Judge solar on its net installed price, financing and current export credits. Also weigh how much of its power you'll use at home and how long you'll own the house. Arizona still offers a state solar tax credit of 25% of the cost, up to $1,000.

Don't count the old 30% federal credit. The federal Residential Clean Energy Credit (Section 25D) is not available for property placed in service after December 31, 2025. The same is true of the federal Energy Efficient Home Improvement Credit (Section 25C), which covered efficient AC and heat pumps. In 2026, both projects have to stand on their own numbers.

When a Battery Beats More Panels

If you already make a big midday surplus, more panels may just mean more low-value exports. A battery can store that extra solar and use it during pricey evening hours instead. But a battery still has to beat simply buying power from the utility. Don't assume it pays for itself just because it shifts solar.

SRP adds another option. Its Renewable Export Program pays an hourly market-based price for exports and is open to customers on an SRP solar export plan. For 2026 enrollments, customers can add a Renewable Capacity Credit of $6.30 per kW per month for each two-hour block they commit. You must deliver at least one two-hour block daily between 5 and 10 p.m., under a five-year contract.

Those hours come after solar fades, so this usually takes a battery. The utility's own pricing is hinting that storage may be worth more than extra panels.

Can a Battery Run Your AC in an Outage?

Be realistic about backup. SRP estimates a central AC draws about 3 kW, which is a big load for a battery. Backing it up can take several battery units, enough inverter output and load-management equipment. That gets expensive fast.

Many homeowners back up the refrigerator, internet, lights, some outlets and maybe a small mini-split instead.

Comfort, Roofs and Failing Systems Can Set the Order

HVAC improves cooling, airflow, noise and room-to-room balance. Solar doesn't. If the upstairs hits 90 degrees every afternoon, a lower bill won't fix the real problem. And if a 17-year-old AC dies in July, you'll replace it whether panels are on the roof or not. When money is tight, a livable home comes first.

The roof matters too. If it's near the end of its life, solar may need to wait, or you could pay later to remove and reinstall the panels. If your AC is old but still works well, plan ahead. A replacement in a few years could cut usage, while a new EV or pool could raise it. Good solar design looks forward.

Four Arizona Examples

Home A: Two 16-year-old AC units, weak attic insulation and 30,000 kWh a year. Best first move: HVAC plus insulation, then resize solar.
Home B: New efficient HVAC, a tight envelope, high daytime use and a great roof. Best next move may be solar.
Home C: Existing solar with a large midday surplus, SRP exports worth only a few cents per kWh and heavy evening use. Best next move may be a battery, not more panels.
Home D: Good HVAC and existing solar, but the pool, dryer and EV all run during expensive peak hours. Best first move: better scheduling and a better-matched rate plan.

AC or Solar First? A Simple Arizona Decision Tree

Is the AC old, failing or inefficient? If yes, HVAC first.
If not, does the home have major attic or duct problems? If yes, efficiency first.
If not, is your rate plan a poor match for when you use power? If yes, fix the plan first.
If not, is yearly usage high, with a good roof? If yes, evaluate solar.
Do you export cheaply but buy expensive evening power? If yes, look at a battery before adding panels.

The Ashborn Approach

Before recommending equipment, Ashborn Partners looks at whether you're with APS or SRP, your past and hourly usage, your peak periods and your demand. We also review HVAC age and efficiency, attic insulation, ductwork, your roof, your solar export plan, battery programs and any EV or pool loads. Then we help you compare options from participating providers serving your area.

In Arizona, fix the load, fix the timing, then decide whether the next dollar belongs on the roof or in a battery.

APS and SRP prices, export credits and rebates can change. Solar cost and savings examples are hypothetical. The federal residential clean energy credit is not available for property placed in service after December 31, 2025.

Solar vs. HVAC in Arizona: Which Should You Do First in 2026?