Seasonal adjustments: retuning your limit twice a year

Set it and forget it is the wrong instinct

Your Demand Limit was commissioned against the loads that were running the week it was installed. Six months later, a different set of appliances is setting your peak. Check the limit at each season change and adjust if the house is telling you to.

Summer: cooling and pool set the peak

From roughly May through October in Arizona, your peak is driven by compressors and pool equipment. Two AC units calling at once, plus a filtration cycle, plus a dryer, is the classic combination that sets a monthly demand charge in a single 30 or 60 minute window.

Winter: heat is the bigger spike

Winter peaks come from a different list: electric strip heat, heat pump auxiliary heat, and water heating.

Resistive backup heat deserves attention. A heat pump with electric strip backup can pull a larger, harder spike on a cold morning than anything your air conditioner does in July, because strip heat is a straight resistive load that comes on all at once. If your home has it, your winter Demand Limit may need to sit differently than your summer one.

Water heating also matters more in winter. Incoming water is colder, so reheat cycles run longer.

Retune at each season change

Two checks a year is enough for most homes.

1. Look at PD, your on-peak peak demand, near the end of the season. Was it holding near your limit or well above it?
2. Adjust DL in 0.5 kW steps and wait at least an hour between changes.
3. Give the new setting a week of normal weather before deciding.

The Demand Limit is still the only setting you adjust. Priorities, timers, and the utility schedule stay with your installer.

Time it against your meter read date

Use the same tactic twice a year. Find the read date on your bill.

• Exiting peak season: lower the limit before the read.
• Entering peak season: raise the limit after the read.

It costs nothing and it keeps a high peak from landing in a billing period you are about to close.

Arizona specifics

Both SRP and APS run separate summer and winter rate structures. The season definitions, the on-peak hours, and the price per kW can all change when the schedule flips, and the on-peak window itself is not always the same block of hours in January that it was in July. Check your utility for current season dates and on-peak hours.

Your unit already holds the correct schedule for your plan. Your installer programmed it and locked it, which is why owners cannot accidentally break the calendar. What changes with the season is your side of it: which loads are running, and where the limit should sit.

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Questions about your own setup? Call toll free (888) 461-9336, direct (970) 461-9600, or email help@energysentry.com. Monday–Friday, 8:00 AM–5:00 PM Arizona time.