Heat pump hot water savings calculator

Compare your current water-heater energy cost with a heat pump supplying the same yearly hot-water heat. Enter useful heat, rather than purchased fuel energy. Useful heat is the heat needed after the current system’s losses. Use an assessment that matches your household and intended water-heating conditions.

Add current system efficiency, fuel price and lower and higher heat pump COP. Enter the shares supplied by solar and off-peak electricity, plus their prices. Include installed price, confirmed rebate and any extra yearly maintenance. The results show energy costs, a net saving range and simple payback for the entered scenarios.

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.

COP means coefficient of performance: heat delivered divided by electricity used. SCOP is this ratio over a season. A ratio of 4 means 4 kWh of heat per 1 kWh of electricity. Use the ratio itself, without a percent conversion.

Use a percentage as a fraction once: for example, 50% means 50 ÷ 100 = 0.5. Use 0.5 in the energy formula; do not divide it by 100 again.

Solar energy is priced at the export income you give up by using it. Off-peak energy uses the separately entered off-peak price. The remaining share uses the ordinary electricity price. Solar and off-peak shares refer to heat pump input energy and cannot together exceed 100%.

Convert cents per kWh to dollars by dividing by 100. Higher COP gives lower electricity use and higher saving. Simple payback divides the net installed quote by positive yearly saving after extra maintenance. A zero or negative saving does not produce a finite payback.

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.

Your heat pump COP bounds must include resistance backup, standing losses and the assessed operating conditions. Use seasonal performance for annual demand. A laboratory COP at one test point may not describe a full year. The tool does not turn local weather or a product label into a property forecast.

Solar and off-peak allocations need to fit the real operating schedule. Annual shares alone do not prove that surplus solar is available when the heater runs. Solar use is not treated as free when it replaces paid exports. Keep those export prices separate from grid purchase prices.

A confirmed rebate is your input, not an eligibility decision. Annual prices and use stay constant. Payback excludes finance, replacement, declining performance and future price changes. Existing supply charges are excluded unless entered in the calculation. Missing personal figures are not guessed. Displayed money is rounded while the underlying working keeps full precision.

Australian published electricity prices use the stored AER or Victorian regulator record for the selected network. These dated reference prices can differ from your own plan. Use tax-inclusive bill prices where they better match the ordinary or off-peak operating window.

Enter the current fuel price and export price in the units beside their fields. A time-of-use plan needs the actual price for the chosen off-peak window. Check source dates for the stored method and rates. Those checks do not confirm a rebate, the household’s hot-water demand or a product’s performance at your site.

Ask a qualified installer to assess hot-water demand, suitable system capacity, operating conditions and required connections. Bring current fuel bills, the proposed model, performance evidence and installation quote.

Ask how backup heating and losses are included in the COP range. Confirm rebate evidence separately. Use the estimate to discuss costs; it does not certify the product, safe installation or eligibility. Follow the maker instructions and local requirements.