Off-peak electricity is power you use during hours when overall demand on the grid is low, typically overnight and on weekends. Because fewer people are drawing electricity at these times, utilities charge a lower rate per kilowatt-hour. Peak rates can run two to three times higher than off-peak rates, so shifting your heaviest energy use to off-peak windows can meaningfully cut your bill.
How Off-Peak Hours Are Defined
The electricity grid follows a predictable daily rhythm. Demand hits its lowest point around 5:00 a.m., climbs through the morning as businesses open and people wake up, peaks sometime during the afternoon or early evening (depending on the season), then drops again late at night. Utilities divide this cycle into pricing windows: on-peak hours generally run from 7:00 a.m. to 11:00 p.m. on weekdays, while off-peak hours cover 11:00 p.m. to 7:00 a.m. on weekdays plus all day on weekends and holidays.
Those are industry-wide conventions, but the exact windows vary by utility. Pacific Gas and Electric in California, for example, offers one plan where 4 to 9 p.m. every day is “peak” and everything else is off-peak. Another PG&E plan narrows the peak window to 5 to 8 p.m. on weekdays only, making all weekend and holiday hours off-peak. Your utility’s specific schedule is what determines when you’re actually saving money, so it’s worth checking.
Why Utilities Charge Less at Night
Power plants can’t easily ramp up and down to match minute-by-minute demand. A baseline level of generation, called baseload, runs around the clock to cover things like refrigerators, servers, and streetlights. When demand spikes during the day, utilities fire up additional, often more expensive generators to meet it. Those extra generators cost more to run, and during extreme peaks the grid can come under strain.
By offering cheaper off-peak rates, utilities give customers an incentive to spread their usage more evenly across the day. This reduces the need for expensive peak-hour generation, lowers stress on transmission lines, and can delay the need to build new power plants. It’s a pricing tool, but it works because the underlying cost of producing electricity genuinely drops when fewer people are using it.
Time-of-Use Plans vs. Flat-Rate Billing
Off-peak pricing only applies if you’re enrolled in a time-of-use (TOU) rate plan. Under the traditional model, called a tiered plan, you pay the same rate per kilowatt-hour regardless of when you use power. The price only increases once you cross a monthly usage threshold into a higher tier. Time-of-use plans flip this: the price changes based on when you use electricity, not just how much.
TOU plans give you more control if you can be flexible about timing. If most of your heavy electricity use already happens outside peak windows, or you’re willing to shift it, you’ll pay less than you would on a flat rate. If your schedule locks you into running appliances during peak hours, a TOU plan could actually cost you more. The savings depend entirely on your habits.
How Much You Can Save
The price gap between peak and off-peak electricity is substantial. In many regions, peak rates range from $0.30 to $0.50 per kilowatt-hour while off-peak rates fall between $0.10 and $0.20. That means running your dishwasher at 10 p.m. instead of 6 p.m. could cost a third as much for the same electricity.
Simple behavioral shifts, like running the washing machine and dryer at night, charging devices overnight, and pre-cooling your home before the peak window, can reduce monthly bills by 15 to 25 percent without any upfront investment. Adjusting thermostat settings alone during peak periods can trim HVAC costs by 20 to 30 percent, roughly $30 to $50 per month for an average household. Pairing those habits with smart thermostats, improved insulation, and efficient appliances can push total electricity savings to 40 to 60 percent.
Smart Meters and How Billing Works
To charge you different rates at different times, your utility needs to know exactly when you used electricity, not just how much you used over a month. That’s where smart meters come in. A smart meter records your consumption in time-based increments and wirelessly transmits the data to your utility, often updating every few hours. This lets the utility apply the correct rate to each block of usage.
Without a smart meter, your usage data is typically only updated monthly, and you won’t have access to real-time information about your consumption patterns. You also won’t receive high-usage alerts or be able to see which hours are costing you the most. Most utilities will install a smart meter at no charge if you switch to a TOU plan, and many areas are rolling them out as standard equipment.
Off-Peak Plans in the UK
In the United Kingdom, off-peak electricity has its own naming conventions. Economy 7 is a tariff that gives you seven hours of cheaper electricity at night, typically from midnight to 7:00 a.m., though the exact window varies by supplier and region. It was originally designed for households with storage heaters that charge up overnight and release heat during the day.
Economy 10 works the same way but extends the cheap window to ten hours: the same seven overnight hours plus three additional hours during the afternoon. Both tariffs charge a higher daytime rate to offset the nighttime discount, so they only save money if you can genuinely shift a large portion of your usage into those windows. If you use most of your electricity during the day, the higher daytime rate on these plans can make them more expensive than a standard flat tariff.
What to Run During Off-Peak Hours
The biggest savings come from shifting your most power-hungry appliances. Electric vehicle charging is the easiest win: most EVs let you schedule charging to start automatically after a set time, so you can plug in when you get home and have it draw power only after off-peak pricing kicks in. Dishwashers, washing machines, and dryers are also good candidates since they don’t need to run at any particular time of day.
Water heaters with timers can heat your tank overnight when rates are lowest. If you have a pool pump, scheduling it to run in the early morning instead of the afternoon avoids peak pricing entirely. Even pre-heating or pre-cooling your home before the peak window starts lets your HVAC system coast through the most expensive hours without working as hard.
Appliances that run continuously, like your refrigerator and internet router, can’t be shifted. These draw what’s called baseload power, and they’ll use electricity across all pricing windows regardless. The strategy is to move everything you can control into off-peak hours and accept the small fixed cost of what you can’t.
Environmental Considerations
Off-peak electricity isn’t just cheaper. It can also be cleaner, depending on where you live and how your grid is powered. During peak demand, utilities often bring older, less efficient fossil fuel plants online to meet the surge. Research on building emissions found that just 1 percent of the year accounted for over 12 percent of annual greenhouse gas emissions, while only contributing about 2 percent of total energy use. That extreme concentration of emissions during peak periods means avoiding those hours reduces your carbon footprint disproportionately to the energy you save.
In regions with significant wind or solar capacity, off-peak hours can also coincide with times when renewable generation exceeds demand. Overnight wind production, for example, sometimes goes to waste because not enough people are drawing power. By shifting consumption to those hours, you’re effectively using electricity that might otherwise be curtailed.