How to actually save money on time-of-use rates
Time-of-use plans punish energy used at the wrong hour — and reward you for shifting it. Here's how to win the game, with or without a battery.
More utilities are moving customers onto time-of-use (TOU) rates, where a kWh costs very different amounts depending on the hour. Used well, TOU can save you money. Ignored, it quietly raises your bill. Here's how to come out ahead.
How TOU works
A TOU plan splits the day into periods — typically off-peak (overnight), mid-peak, and on-peak (usually around 4–9 PM). On-peak power can cost 2–4× off-peak. The whole strategy is simple to state: use less during peak, more during off-peak.
The moves that matter most
- Shift your EV charging to off-peak. This is the biggest single lever for most households. Charging a car at 1 AM instead of 6 PM can save hundreds a year on its own.
- Run big appliances off-peak. Dishwasher, laundry, pool pump — schedule them for late night or midday, not the dinner-hour peak.
- Pre-cool before peak. Run AC harder at 3 PM so it coasts through the 4–9 PM peak with less work.
- Avoid peak EV charging entirely unless your battery is covering it.
Where a Powerwall changes the game
A battery lets you "buy low, use high" with electricity: store cheap off-peak or solar energy and discharge it during the expensive 4–9 PM window so you barely touch the grid at peak. The key is that the battery must hold its charge until peak rather than self-powering the moment the sun dips — a common misconfiguration that wastes the stored energy too early.
If you have solar + EV + battery
This is where it gets genuinely complex: you want to charge the car off-peak (or on a special EV rate window), hold the Powerwall for peak, and account for what your solar exports are worth under NEM. Coordinating all three by hand, every day, against your exact plan is more than most people will keep up. SolDial automates the whole loop — it knows your TOU windows, schedules EV charging into the cheap hours, and times the Powerwall to cover your peak.
Start here
Even without any hardware: move your EV charging and big appliances off the 4–9 PM peak, and you'll likely see the difference on your next bill.