How to Pre-Cool Your Home Before Peak TOU Rates Hit

If you’re on a time-of-use (TOU) electricity rate plan (or thinking about switching to one) summer is the season that makes or breaks your energy bill. Sacramento summers are no joke, and the way most people respond to the heat (crank the AC when they get home from work) happens to align almost perfectly with when electricity costs the most.

The good news is that with a little planning, you can stay cool and keep your bill in check. The strategy is called pre-cooling, and once you understand how it works, it’s surprisingly simple to pull off.

What Are TOU Rates, and Why Do They Matter in Summer?

Time-of-use (TOU) rates are electricity plans where prices vary depending on the time of day. Instead of paying a flat rate, electricity costs more during high-demand hours and less when demand is low.

In California, peak rates are from 4 PM to 9 PM at the time of publication. Why?

• Solar energy decreases, putting a greater load on the grid. 
• More time is spent at home instead of shared spaces (like schools, office buildings, gyms, etc).
• This is also the time for watching television, gaming, using appliances, and other electricity-consuming items.
• Toward the end of this window, the sun goes down, and lights go on throughout homes across the city. 
• This window is also when homeowners fire up their air conditioning systems during the summer.

Depending on where you live and the time of year, electricity costs can nearly double during this window.  The fix isn’t to suffer through the heat during peak hours. It’s to get your home cold before those hours begin, which can lower your AC load during the most expensive windows of cooling.

How Pre-Cooling Actually Works

Think of your home like a lunch box. If you fill it with ice packs in the morning, it stays cold for hours. Pre-cooling works the same way. You run your AC harder during off-peak hours (when rates are lower). By the time energy rates increase, you can turn off your AC for a few hours without sacrificing comfort

Here’s the basic approach:

• Identify your peak window. For most Sacramento-area customers on PG&E TOU plans, peak hours run from 4 PM to 9 PM daily in summer. Check your specific plan to confirm.
• See if you have any morning lulls. For example, if your family is out of the house for work or summer camp every day from 9 AM to 1 PM, this is a good time to save money by slightly raising your thermostat.
• Start pre-cooling 2–3 hours before peak rates begin. Aim to get your home down to a comfortable temperature (or even a degree or two lower) before 4 PM.
• Let the thermostat rise slightly during peak hours. Raise your thermostat a few degrees during the on-peak window to maintain comfort using that pre-conditioned air. 
• Return to normal settings after 9 PM, when off-peak rates resume.

It sounds almost too simple, but it genuinely works, especially in well-insulated homes.

How to Make Pre-Cooling Your Home Easier

You don’t have to manually babysit your thermostat to pull this off. The right equipment does the heavy lifting for you.

Smart Thermostats

A programmable or smart thermostat is the single best tool for TOU management. You can set a schedule that automatically pre-cools before peak hours and eases back during them. Some models even have built-in TOU rate awareness and will optimize your schedule automatically based on your utility’s pricing. 

Thermostat Apps

Most smart thermostats also have an app you can download and connect to with your phone. Use the app to make adjustments throughout the day as your summer schedule shifts to easily maximise comfort or save even more money. 

For example, let’s say if you are at the beach with your family, and you make plans to go out to dinner instead of heading home that evening. Once your schedule changes, you can use the app to skip the pre-cool for the day. 

Ceiling Fans

Ceiling fans don’t lower the temperature, but they make a room feel cooler using the wind chill effect. Running ceiling fans during peak hours lets you tolerate a slightly higher thermostat setting without noticing the difference, which is exactly what you want. Just remember to turn them off when you leave the room to avoid wasting electricity during peak hours.

Window Coverings

Close your blinds and curtains before the afternoon sun hits them. South- and west-facing windows let in enormous amounts of heat during peak hours. Keeping them covered can reduce how quickly your pre-cooled home warms back up, extending the benefit of all that morning AC work.

Other Energy Shifts That Amplify Your Savings

Pre-cooling your home is the biggest lever you can pull, but it works even better when you shift other high-draw tasks out of peak hours too. Here are a few easy ones:

• Dishwasher: Your dishwasher generates heat and uses significant electricity. Thankfully, all modern dishwashers (and even most older units) have a scheduling feature. Schedule your dishes to run after 9 PM or before noon. 
• Oven cooking: Cook with a microwave, air fryer, or slow cooker instead of the oven during peak hours. Ovens heat up the kitchen and force your AC to work harder.
• Pool pumps: If you have a pool, schedule the pump to run overnight or early morning, not during the 4-9 PM window.
• EV charging: Many EV apps let you schedule charging overnight, which is when rates are at their lowest. If you haven’t set this up yet, it’s one of the easiest ways to cut your bill.
• Dryers: Like ovens, dryers generate heat and use a lot of electricity. Push laundry to evenings after peak ends or early mornings.

None of these changes require a major lifestyle overhaul, they’re mostly just timing shifts.

Is Your Home Leaking Cool Air?

Pre-cooling works best when your home retains what your AC puts into it. If cool air bleeds out quickly, you’ll be fighting an uphill battle. A few things worth checking:

• Air filter: A dirty filter makes your AC work significantly harder to move the same amount of air. Change it every 1–3 months, depending on your system and home.
• Attic insulation: The attic is one of the biggest sources of heat gain in Sacramento homes. Adequate insulation keeps that radiant heat from cooking your living spaces during afternoon peak hours.
• Door and window seals: Weatherstripping and caulking around drafty doors and windows is inexpensive and makes a meaningful difference in how long pre-cooled air stays put.
• AC tune-up: An inefficient or poorly maintained AC system can’t pre-cool effectively, even if you’re running it at the right time. If your system hasn’t been serviced recently, a seasonal tune-up before summer hits is worth every penny.

When Your Electrical System Is Part of the Problem

Do you have an aging electrical panel, old light fixtures instead of LEDs, or an HVAC system that’s drawing more power than it should due to wiring issues? Issues like these can undermine your efficiency and your savings, especially during peak hours. 

If your AC trips breakers, lights dim when you use certain appliances, or you’re planning upgrades like a smart thermostat, ceiling fan, or EV charger, it’s worth having a licensed electrician take a look before summer hits.

Choose Bonney AC and Home Efficiency Services in Sacramento

Sacramento summers are long, hot, and expensive if you’re not strategic about them. Pre-cooling is one of the most effective ways to stay comfortable while keeping your TOU costs in check. Whether you need an AC tune-up, air conditioner repair, or help ensuring your home’s electrical setup is ready to support an efficient summer, the local experts at Bonney are here to help. Explore the Bonney Beyond maintenance program, give us a call, or view our coupons to get started today!