Time-of-use tariffs charge different electricity prices at different times. Their practical effect depends on the household's consumption pattern, the size of the price differences and any fixed charges. A low overnight rate is only one part of the bill. Expensive periods may offset the saving if much of the household demand remains there.
Reconstruct a representative week
Use interval data if available, or a careful estimate of major loads. Identify tasks that can move and those that cannot. Electric vehicle charging and water heating may offer flexibility, but cooking and occupancy patterns may be less adjustable. Include seasonal changes rather than assuming every week looks like a mild spring week.
Read the complete tariff
Check time windows, weekend treatment, standing charges, export rates and any conditions attached to the offer. Rules vary by supplier and location. A battery calculation should include charging losses and control behavior. Do not multiply one attractive rate by all annual consumption unless all that consumption really occurs in the eligible period.
Test the routine before committing
Where possible, simulate the schedule using existing controls and review whether it is convenient. Keep essential services and comfort needs intact. A tariff should fit a workable routine rather than require constant attention. Compare total estimated bills under several realistic patterns and revisit the decision when circumstances change. The useful outcome is a transparent match between a household's flexible demand and a specific price structure, with the less attractive parts of that structure still included in the arithmetic.
