Time of use vs tiered calculator (Ontario)

Compare Ontario Time-of-Use, Ultra-Low Overnight and tiered electricity prices for the same household use. Time-of-Use, or TOU, changes price by time and day. Ultra-Low Overnight, or ULO, has its own time windows. Tiered pricing changes after a set amount of monthly electricity.

Enter household kWh in all eight time windows shown. These windows divide the month without overlap, allowing the same usage to be priced under all three plans. Count each kWh once. Do not put the whole bill total in more than one window. Use meter records rather than guessing when a large appliance ran.

Choose a representative summer or winter month for manual entry. Use published OEB prices or enter all the matching prices and tier allowance from your plan. The result compares this month's electricity line. It does not assume you will change the times you use electricity after switching plans.

Sum the same metered household kWh in eight nonoverlapping OEB time windows using each plan price. Tiered cost = min(total kWh, threshold) × first-block price + max(total − threshold, 0) × second-block price. Select a representative summer or winter month; prices and thresholds may be entered from your own bill.

For TOU and ULO, multiply the kWh in each window by the price assigned to that window, then add the costs. Prices entered in cents per kWh are divided by 100 to give Canadian dollars. The cheapest overnight price does not always make ULO cheapest overall; higher-priced hours also affect the total.

For tiered pricing, fill the first block up to its allowance, then price any remaining kWh at the second price. The result shows each plan's total and identifies the lowest electricity-line cost for the usage you entered. Compare the cost difference as well as the name of the lowest plan.

These illustrative inputs are separate from your saved answers. Prices, use and performance are held constant for this worked scenario; they are not personal defaults.

This worked example uses the dated OEB snapshot shown in its rate inputs.

The estimate includes the electricity line and Global Adjustment. It leaves out delivery, line-loss adjustment, regulatory charges, tax and rebates. The result is therefore a plan comparison for this part of the bill, not the complete amount your utility will collect.

Manual entry uses one representative seasonal profile. A bill that crosses seasons or price changes may need dated interval records for a closer comparison. One month does not establish which plan will be cheapest for a full year.

For imports, use one complete supported calendar month, select the meter's local time zone and enter the utility-confirmed tier allowance for that exact period. The file must contain the required dated readings. Missing intervals or unsupported units stop the import; no missing use is invented. Files are processed on your device, and source details stay with the saved result.

OEB means the Ontario Energy Board. Its published prices, time windows and seasonal thresholds apply only to the period recorded with the data. Check the linked source and your own bill before using a stored price.

Utility-confirmed allowances may depend on the dates and billing days involved. Enter prices and thresholds that belong together. Your personal inputs are labelled separately from the published data and are not verified by the calculator.

Ask your utility to confirm your current pricing plan, whether you can switch and the applicable date. Ask for help obtaining interval readings if your bill gives only a monthly total.

Before moving major loads to cheaper hours, check appliance timers, household needs and any equipment limits. An energy adviser can help review several seasons of records. The calculator does not promise savings from a schedule your household cannot follow.