On a demand plan, the bill reacts to your highest burst of power, not only your total use. That is why running the AC, oven and dryer at the same moment can cost more than running them one after another. TEP lists Demand Time-of-Use (Demand TOU) as an alternative residential plan, as of October 2026. Climate Pros Tucson isn’t TEP and can’t pick a plan for you, but we can show you how to test one against your own house.
What is a demand charge?
A demand charge bills the highest rate of power you draw during a set window, not the total energy you use. The two are different units. One kilowatt (kW) is 1,000 watts of power at a moment. One kilowatt-hour (kWh) is one kilowatt used for one hour, according to the U.S. Energy Information Administration.
Picture two houses that use the same kWh in a month. One spreads its big loads across the evening. The other runs the AC, oven and dryer all at 5 p.m. On a plan that measures demand, the second house has the higher peak, and that peak is what gets billed.
TEP’s Demand TOU page explains how it measures demand and which hours count. Read it before you compare anything, because the window and the rates are TEP’s to set and TEP’s to change.
Which TEP plans are in play?
As of October 2026, TEP lists Time-of-Use as its residential plan, with Basic, Peak Demand and Demand TOU as alternatives. On the time-of-use plan, the summer on-peak runs May to September, Monday to Friday, 3 to 7 p.m., and the winter on-peak, October to April, runs weekdays 6 to 9 a.m. and 6 to 9 p.m. (tep.com/time-of-use). Demand TOU’s own measuring window is set on its page, so don’t assume it matches. For a side-by-side of every plan, see the best TEP rate plan for AC.
Trico Electric Cooperative serves northwest Tucson and Marana south to Green Valley and Sahuarita. If Trico is your utility, none of this applies. Ask Trico which plans it offers.
Why do the AC and big appliances stack up?
Tucson’s AC runs hardest when the day is hottest. The 1991-2020 normals at Tucson International Airport put June’s normal high at 101.2F and July’s low at 76.3F, so the house stays warm into the night. On a summer afternoon the AC may run for long stretches, so anything else big you switch on lands on top of it.
The usual stackers:
- The oven or range during dinner prep.
- The clothes dryer.
- An EV charger plugged in when you get home.
- A pool pump set to run through the afternoon.
- Electric strip heat in winter, if your heat pump has it (see heat pump mornings on TEP’s winter peak).
Staggering means moving the movable ones. Run laundry and the pool pump earlier or later. Schedule the EV charger for overnight. The AC is the one load you can’t skip, so leave room around it.
Who does Demand TOU fit?
It tends to suit a house whose big loads are easy to schedule: a pool pump on a timer, a charger on a schedule, laundry on weekends. It tends to fit worse when several people are home on weekday afternoons and everything runs at once.
That’s a pattern, not a prediction. Before you switch, write down when your big loads run on a normal weekday, then ask TEP to run your actual usage against Demand TOU and check tep.com/rates for current terms. Recheck after any big change, like a new system, an EV or a new work schedule.
Does a new system change the answer?
It can. A properly sized, matched system may draw its power more evenly than an older one that strains on a hot afternoon. A variable-speed unit ramps up and down instead of cycling hard. Ask the pro you’re matched with what the equipment’s startup and running draw look like on the model’s spec sheet.
A smart thermostat helps because the schedule runs without you. If the bill is high on any plan, see why your TEP bill is so high in summer. The Tucson HVAC hub shows the area we cover.
When the system is the real load
If the AC runs nonstop and the bill still climbs, the system may need a look before any plan change helps. Call (520) 353-2520 and we’ll match you with a licensed local pro. Ask the pro whether your system is sized and running as it should.