Heat pump hot water savings calculator

Compare the current water heater with a heat pump water heater for the same yearly hot-water heat. Enter useful heat delivered to the water, rather than the energy bought to run the old system. An installer can help separate this from other household energy use.

Choose the old heater's fuel, matching unit price and efficiency. Enter lower and higher assessed COP values for the heat pump. COP describes heat delivered for each unit of electricity. The range lets you test two seasonal performance assumptions while holding hot-water demand unchanged.

If relevant, enter separate shares for solar electricity and grid off-peak electricity. Solar is valued at export income you give up by using it. Off-peak use needs its own price and supported operating schedule. Add the installation quote, a confirmed rebate and extra yearly maintenance to estimate net savings and simple payback.

Current cost = annual useful heat ÷ current efficiency × fuel price. Heat pump energy = heat ÷ COP. Its weighted price accounts for solar export forgone and separately entered grid off-peak use. Saving = current cost − heat pump cost − extra maintenance. Net quote = installed price − confirmed rebate.

A COP of 3 means 3 kWh of heat for 1 kWh of electricity. Use that ratio directly. Convert efficiency and energy shares to fractions once: 50% means 0.5. Prices entered in cents per kWh are divided by 100 to give dollars. Convert a gas bill price to the required energy unit before entry.

The solar and off-peak shares are separate parts of the heat pump's electricity. Together they cannot exceed 100%. The remaining share uses the selected ordinary grid price. The higher COP produces the lower running cost and larger saving. The working shows the weighted price, energy use and quote after rebate.

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.

Assess COP for the proposed location and season, including resistance backup, storage losses and the equipment's real operating conditions. The calculator does not infer this performance from the product name or supply a missing household hot-water demand.

Annual totals do not prove that solar or off-peak electricity is available when the heater runs. Use monitored records or an installer schedule for those shares. Do not count the same electricity in both shares. An existing solar system's purchase cost is outside this changeover estimate.

Simple payback divides the quote after rebate by positive yearly savings after extra maintenance. Nonpositive savings have no finite payback. Prices and use stay fixed; borrowing, equipment replacement and future price changes are excluded. Existing supply charges are outside the energy comparison. Personal fields start empty, and incomplete edits keep the last valid result with a warning.

The published electricity option uses EIA state residential averages for July 2026, released on 24 September 2026 and checked on 14 October 2026. These describe past average prices. They are not your supplier's offer or a promise of future prices. Choose your bill price for a personal comparison. Include the taxes and usage charges that change with consumption; keep fixed account charges separate.

No federal 25C credit is included for 2026 projects. Enter only a separately confirmed eligible rebate, and do not subtract a discount twice. Check the source dates and the written terms of your own offer.

Ask a qualified water-heater installer to confirm hot-water demand, usable tank capacity and the seasonal COP range. Ask how backup elements and the chosen heating schedule affect performance.

Before buying, check the installation space, electrical work and any ventilation, drainage or plumbing needs. Bring the quote, tariff and rebate evidence. This estimate cannot confirm product suitability, incentive eligibility or safe installation, and it does not guarantee the calculated savings.