Cheapest & Most Expensive Hours for Dynamic Tariff Electricity Prices | WattSmart

WattSmart helps you quickly spot the cheapest and most expensive time intervals - hours or 15-minute intervals - based on official day-ahead electricity market prices for your zone.

Cheapest and most expensive hours or 15-minute intervals

If you’re on a dynamic tariff, price can change a lot during the day. This feature makes it easy to see when electricity is cheap and when it’s expensive, so you can plan flexible usage without digging through charts.

What you get

• Cheapest intervals - the lowest-price periods of the day, ideal for laundry, dishwashers, EV charging, water heating, and other flexible loads.
• Most expensive intervals - peak-price periods you may want to avoid when possible.
• At-a-glance grouping - intervals are grouped into “cheap” and “expensive” so you can make a quick decision, not compare dozens of numbers.

Cheapest hours (or 15-minute intervals): how it works

It highlights the cheapest and most expensive hours and can also show 15-minute intervals depending on your settings. WattSmart uses day-ahead prices and highlights:

• intervals that are below your acceptable range (cheapest),
• intervals that are above your acceptable range (most expensive).

Your “acceptable range” is based on the average price option selected in settings and your deviation setting. This keeps the “cheap vs expensive” view consistent with how you personally judge prices.

For the full explanation of averages and price levels, see: Electricity Price Comparison with Averages.

When this feature is most useful

• You have a dynamic electricity tariff and want to shift usage to cheaper intervals.
• You want a simple answer to: “When should I run appliances today?”
• You want to reduce cost with minimal effort - just avoid the most expensive intervals when you can.