Energy Bills Resource

Interactive Sizing & Electrical Reference

The Shift in Utility Pricing

For decades, electricity was billed at a flat rate. A kilowatt-hour (kWh) cost the same whether you used it at 3:00 AM or 3:00 PM. But as the electrical grid faces higher demands and integrates renewable energy, utility companies are aggressively transitioning to Time-of-Use (TOU) pricing.

Under a TOU plan, the cost of a kWh fluctuates depending on the time of day, the day of the week, and the season. Electricity is cheap when demand is low (off-peak) and very expensive when demand is high (on-peak).

Key Concept: With TOU rates, a 1500W appliance might cost 15 cents to run per hour in the morning, but 45 cents to run per hour in the late afternoon.

Understanding the timing of your wattage usage is now just as important as reducing the total watts you use.

Navigating Peak vs Off-Peak Hours

While specific times vary by utility, a typical summer TOU schedule looks like this:

  • Off-Peak (Cheapest): Midnight to 2:00 PM. (Rate: ~12¢/kWh)
  • Partial-Peak (Moderate): 2:00 PM to 4:00 PM, and 9:00 PM to Midnight. (Rate: ~20¢/kWh)
  • On-Peak (Most Expensive): 4:00 PM to 9:00 PM. (Rate: ~35¢ to 50¢+/kWh)

Strategies to Master TOU Rates

You don't need to sit in the dark during peak hours, but you do need to shift high-wattage loads away from the expensive window.

Appliance TOU Strategy
EV ChargerSet a schedule in the car's app to only charge after midnight.
DishwasherUse the "Delay Start" button to run the cycle at 1:00 AM.
Air ConditionerPre-cool the house to 68°F during off-peak hours, then raise the thermostat to 76°F during peak hours.
Pool PumpAdjust mechanical timers so the pump runs in the early morning instead of the afternoon.
LaundrySave heavy washing and drying for weekend mornings (which are often considered off-peak all day).
Warning: Running an electric oven or a clothes dryer during a 50¢/kWh peak window can be incredibly expensive. Avoid using these heat-generating appliances between 4 PM and 9 PM.

Frequently Asked Questions

1. Are Time-of-Use rates mandatory?

In many states (like California), TOU rates are now the default for new customers. Some utilities allow you to opt-out into a flat tiered rate, but you have to specifically request it.

2. Do weekends have peak hours?

Under most TOU plans, weekends and major holidays are considered off-peak all day, making them the perfect time to do laundry.

3. How do solar panels interact with TOU?

Solar is highly beneficial under TOU. If you produce solar energy during peak late-afternoon hours and send it to the grid, you get credited at the expensive peak rate!