Move the Timer Before Replacing the Pump

An SRP customer can capture a modeled $283 in average annual savings by moving an existing pool pump into the utility’s lower-priced period, without replacing the pump. Against a quoted $600–$1,200 variable-speed replacement, that equals roughly 2.1–4.2 years of the modeled scheduling savings. The first variable to check is when the pump runs, not which pump is installed (Utility Dive).

That verdict is limited to customers on a qualifying time-varying plan whose pumps currently run during expensive hours. A timer change produces no time-of-use saving on a flat-rate plan, and a variable-speed pump can still reduce total energy consumption. Scheduling and efficiency are separate benefits and should be calculated separately.

Choose your utility, plan, pump schedule, and replacement quote; the calculator shows which step wins for your inputs.

The Case for Replacing a Single-Speed Pump

The usual recommendation has a sound engineering basis. A single-speed pump operates at one fixed speed, while a variable-speed pump can assign different speeds to filtration, priming, cleaning, heating, and salt-system operation. Lower-speed operation can reduce total kilowatt-hours when the hydraulic system and connected equipment permit it.

An Arizona pool company describes single-speed operation at roughly 3,450 RPM and a common variable-speed range of approximately 600–3,450 RPM. It identifies heavily used, failing, or noisy single-speed pumps and systems needing adjustable flow as stronger replacement candidates. The company has a commercial interest in upgrades, and its discussion does not establish a universal saving percentage or payback period, but the operating distinction is valid (Marlin Pools).

Replacement is therefore reasonable when measured consumption is high, the existing pump needs repair, or connected equipment benefits from adjustable flow. Utilities and pool companies are also right that speed control can improve how a system performs different tasks.

What does not follow is that replacement must be the first cost-saving step. A healthy single-speed pump running through an expensive rate window may have a free scheduling opportunity. Buying a more efficient pump without first correcting that schedule solves efficiency while leaving the rate-plan variable unchecked.

The Utility Model Assumes Existing Pumps Are Retimed

The June 12, 2026 analysis by researchers from Arizona State University’s Laboratory for Energy And Power Solutions modeled the existing pool-pump stock rather than requiring replacement equipment. Its representative Arizona pump was a roughly 1–1.5 horsepower single-speed unit operating for an average of four hours per day.

Under those assumptions, the researchers estimated:

• $134 in average annual savings per APS pool owner
• $283 in average annual savings per SRP pool owner
• $83 million in combined annual customer savings: $25 million in APS territory and $58 million in SRP territory
• Approximately 3,280 MWh of electricity shifted per day
• Up to 820 MW of shifted demand

The model used approximately 505,000 residential pools statewide. Its estimated infrastructure value was $66–$164 million per year, based on avoided-capacity values of $80–$200 per kW-year. Those system benefits come from moving controllable demand, not from assuming that every owner installs new hardware (Utility Dive).

These are modeled advocacy estimates published as an opinion analysis. They are not measured results from a completed utility program, utility guarantees, or forecasts for an individual house. They establish the potential scale of retiming; they do not promise that every SRP customer will save $283.

The individual result can be lower or zero when the pump is already off-peak, the account is on a flat rate, the measured load is lower, or required operation cannot be moved. Demand charges, solar terms, seasonal prices, and other household loads can also change the bill result.

E-28 Makes Midday the Relevant SRP Window

SRP’s E-28 time-of-use rate launched in November 2025 with an 8 a.m.–3 p.m. lower-priced window. The pool-pump analysis found that shifting existing operation into that period could produce the modeled $283 average annual SRP saving.

That changes the familiar advice to run a pool pump at night. “Off-peak” is not a universal clock time. It is whatever the customer’s exact tariff defines as cheaper. On E-28, the relevant opportunity is midday.

A four-hour pump cycle from 4–8 p.m. sits entirely outside the 8 a.m.–3 p.m. target window. If pool operation permits, moving that cycle to 10 a.m.–2 p.m. addresses the scheduling variable without changing the motor. A pump already running from 10 a.m.–2 p.m. has no further E-28 retiming opportunity in this simplified comparison; replacement efficiency must then be evaluated on its own merits.

The $283 figure should not be applied mechanically to every schedule. It is the model’s average annual SRP result under its assumptions. The calculator scales that benchmark only to show how much of a four-hour modeled shift remains. A household estimate needs the effective tariff, measured pump demand, and actual movable hours.

APS and Other SRP Plans Produce Different Results

The APS plan documented here is Time-of-Use 4pm–7pm Weekdays. Its summer period covers May through October, with displayed prices of 34.396¢/kWh on-peak and 12.345¢/kWh off-peak. Winter covers November through April, with 32.543¢/kWh on-peak, 12.351¢/kWh off-peak, and 3.495¢/kWh during the weekday 10 a.m.–3 p.m. super-off-peak period.

For a measured 1 kW pump shifted for three hours, the illustrated savings are:

The APS summer calculation is 1 kW multiplied by 3 hours multiplied by $0.22051, which equals $0.66153. The winter calculation uses a $0.29048 spread and equals $0.87144. Confirm current terms on the official APS plan page.

SRP Conserve has a 6–9 p.m. peak. For July and August, its displayed rates are 40.20¢/kWh on-peak, 12.76¢/kWh off-peak, and 6.61¢/kWh super off-peak. Moving a 1 kW load for three hours from peak to super off-peak yields $1.0077 per eligible day.

Manage Demand has a 5–10 p.m. peak, with displayed energy prices of 16.54¢/kWh on-peak, 9.96¢/kWh off-peak, and 6.22¢/kWh super off-peak. It also has a demand charge based on 60-minute on-peak intervals, so an energy-rate calculation alone is incomplete. Pump operation must be considered alongside air conditioning, EV charging, dryers, cooking equipment, and other simultaneous loads.

SRP Basic and M-Power charge the same energy price regardless of operating hour. Retiming creates zero time-of-use energy-price savings on those plans. A different schedule may still help with noise, equipment coordination, or rooftop-solar self-consumption, but those are separate effects.

The SRP comparison prices excluded a temporary $0.0038/kWh reduction for May–October 2026 billing cycles, with displayed prices scheduled to return in November 2026. SRP also offered a 90-day plan trial with the option to return to the previous plan. Current prices and plan rules belong on the customer’s bill and the official SRP comparison, not in a permanently programmed assumption.

No TEP schedule is calculated here because the draft evidence does not supply a current official TEP tariff and time window. The calculator marks TEP results as unavailable rather than borrowing APS or SRP terms.

Calculate Retiming Before Calculating Replacement

Energy-charge savings equal pump kilowatts multiplied by hours genuinely shifted multiplied by the original rate minus the new rate.

Use measured electrical demand at the operating speed involved. Rated horsepower is not the same as electrical input. If monitoring reports watts, divide watts by 1,000 to obtain kilowatts; a 750-watt reading is 0.75 kW.

Count only hours moved out of a more expensive period. If an eight-hour cycle includes two peak hours, no more than two hours belong in the direct scheduling calculation. Moving operation between two periods both priced at 12¢/kWh produces zero rate-based saving: 1 kW multiplied by 3 hours multiplied by $0 equals $0.

For a variable-speed pump, calculate each segment separately. Low-speed filtration, cleaner operation, heater support, salt-cell flow, and priming may all have different measured loads. Segment scheduling savings equal that segment’s measured kW multiplied by shifted hours multiplied by its rate difference.

Then keep the two mechanisms separate:

• Scheduling saving: the same electricity is purchased at a lower price.
• Efficiency saving: fewer kilowatt-hours are consumed because of different pump operation or equipment.

A replacement payback period is the installed cost minus any verified rebate, divided by measured or credibly estimated annual efficiency savings. The available evidence does not provide a universal variable-speed annual saving, verified installation cost, or payback period. That is why the calculator asks for the owner’s quote and projected annual efficiency saving rather than inventing them.

At the documented $283 scheduling benchmark, $600 equals about 2.1 years of savings and $1,200 equals about 4.2 years. This comparison does not mean a replacement saves $283 annually. It shows the amount of no-hardware scheduling value that should be checked before committing capital.

Retiming Must Preserve Pool And Equipment Requirements

A cheaper hour is useful only when the pool can operate correctly during it. Preserve the flow and runtime required for filtration, sanitation, heaters, cleaners, water features, and salt systems. Do not force a long low-speed cycle into a short price window by arbitrarily cutting needed runtime.

SRP’s broad guidance suggests approximately 8–12 pump hours per day in summer and 6–8 in winter, while the ASU model uses a four-hour average. Neither figure is a prescription for every pool. Required operation depends on pump speed, pool volume, debris, water chemistry, filtration, weather, plumbing resistance, and connected equipment.

Record every current start time, stop time, and speed before changing the controller. Check for cleaner cycles, manual overrides, freeze protection, and automation commands that can run the pump outside the main schedule. After retiming, monitor water clarity, sanitizer readings, filter pressure, salt-cell flow, heater and cleaner operation, pump alarms, and utility interval data.

Variable-speed equipment commonly uses 240-volt circuits and requires code-compliant grounding and bonding. Follow the manufacturer’s instructions and applicable electrical requirements rather than improvising wiring changes.

A timer reset is the right first move only when the rate plan rewards it and the pool permits it. Once that free scheduling correction is made, measured energy use can show whether a variable-speed replacement still earns its cost.