Heat Pumps on Time-of-Use Rates: Off-Peak Heating Strategies
Heat pumps are quietly becoming the default choice for home heating and cooling in much of the country, and for good reason: they move heat instead of generating it, which makes them remarkably efficient per unit of electricity. But on a time-of-use (TOU) rate, where a kilowatt-hour at 6 PM can cost two or three times what the same kilowatt-hour costs at midnight, how you schedule a heat pump starts to matter as much as how efficient it is. The good news is that houses store heat, thermostats run schedules, and a handful of deliberate habits can shift most of your winter heating into the cheap hours without leaving anyone cold. This guide walks through the strategy step by step.
Why Heat Pumps and Time-of-Use Rates Interact Differently
A gas furnace buys its fuel on a gas meter, so its electricity profile barely matters. A heat pump moves one hundred percent of its heating energy onto your electric bill, which means the price signal of your rate plan now applies to your single largest seasonal load. The U.S. Energy Information Administration publishes detailed data on how retail electricity prices vary across hours, utilities, and seasons, and in many TOU plans the gap between peak and off-peak rates is wide enough to change behavior.
The key insight is that a heat pump does not care when it runs nearly as much as you do. Unlike a furnace cycle, which blasts hot air for minutes, a heat pump prefers long, steady runs that hold a consistent temperature. That behavioral trait is exactly what you want when your goal is to concentrate consumption inside a cheap overnight window and let the house coast through the expensive one.
Map Your Utility's Peak and Off-Peak Windows First
Every strategy in this article depends on knowing your actual rate schedule, so start there. Pull a recent bill or log into your utility account and find the TOU period definitions: most utilities split the day into two to four blocks, such as off-peak overnight, mid-peak shoulder hours, and a peak window of four to six hours in the late afternoon and evening. Check whether the definitions change by season, because winter peaks often shift earlier and land on cold mornings, precisely when heating demand is highest.
Write the windows down in plain language and stick them to the fridge. According to the Energy Information Administration's Residential Energy Consumption Survey, space heating is consistently among the largest energy end uses in American homes, so getting the schedule right for this one appliance moves more dollars than optimizing everything else combined. If your utility offers an EV or whole-home super-off-peak rate, price it out too; the cheapest overnight block is where a heat pump does its best work.
Pre-Heating: Shift Warmth Into Cheap Hours
Pre-heating is the core tactic. In the final hours of your off-peak window, let the thermostat run one or two degrees warmer than your usual comfort setting, banking extra heat in the air, the furniture, and the walls. When the peak window begins, ease the setpoint down by two to four degrees. The house then coasts on the warmth you bought at the cheap rate instead of buying new heat at the expensive one.
Two cautions keep this strategy honest. First, avoid deep setbacks of eight or ten degrees during peak hours, because a heat pump forced to recover a large gap quickly may call on its electric resistance backup strips, which are the most expensive way to make heat in your home. Second, remember that coasting works best in a tight house: air sealing and insulation determine how long your banked warmth lasts. If you have not yet done a walkthrough for leaks at the attic hatch, outlets, and rim joists, that project pays for itself twice, once on the heating bill and again on the pre-heating strategy.
Building a Weekday Heating Schedule That Sticks
Turn the tactic into a weekly thermostat program. On a typical winter weekday with an evening peak from 4 to 9 PM, a workable pattern looks like this: begin warming toward your daytime comfort setting during the last off-peak hours before the household wakes; hold a steady temperature through the morning; drift down a degree or two through midday when activity and sunshine help; pre-heat again in the final off-peak hour before peak begins; then settle into a gentle two-to-four-degree setback for the evening and recover fully after the peak closes.
Weekends deserve their own program, since occupancy patterns flip: people are home all day, and some utilities flatten or shorten their weekend peaks. If your thermostat supports room sensors, weight the schedule toward occupied rooms so you are not paying to pre-heat a home office that sits empty on Saturdays. Give any new schedule a full two weeks before judging it, and keep notes on comfort complaints, because a plan the family vetoes is not a plan, it is an argument.
Pairing Solar and Battery Storage With Heat Pump Load
A rooftop solar array changes the arithmetic in a helpful way. Winter TOU peaks tend to sit in the dark hours, when your panels are idle, but midday production can still cover part of the heating day, and on net-metering or TOU export plans the electricity you push out at midday rates offsets what you pull in the evening. The U.S. Department of Energy's energy efficiency resources are a solid starting point for sizing a system against a heat pump load.
A home battery completes the loop: charge it from midday solar or overnight off-peak power, then discharge it across the peak window while the heat pump runs its setback. Be realistic about sizing, because cold-snap heating draws are large and sustained, and a modest battery will cover the peak hours rather than the whole night. Even partial coverage trims the most expensive kilowatt-hours from the bill, and many households find that pairing a small battery with disciplined pre-heating beats buying a giant battery and changing no habits at all.
Measuring Savings Month Over Month
Finally, close the loop with measurement. Most TOU bills break usage into peak, off-peak, and shoulder categories; record those numbers monthly rather than staring at the total, because the goal is specifically to shrink the peak column. Weather-normalize your comparison using heating degree days so that a mild December does not flatter the strategy or a brutal one bury it, and track the share of total heating energy that lands in off-peak hours as your headline metric.
EnergyIQ automates this bookkeeping: it pulls your TOU breakdown, aligns it with weather data, and shows exactly how much of your heat pump load shifted into cheap hours each month. See what each plan includes on the EnergyIQ pricing page.