Energy & electrical
Running energy and cost
- where
- energy (J; the calculator shows kWh)
- heat / power rate (W; any unit you pick is converted)
- operating time (s; any unit you pick is converted)
- running cost (£)
- unit energy price (tariff) (£/J; any unit you pick is converted)
Explain this equation
Works out the energy used and running cost of an appliance over a period. Use it for quick cost comparisons.
P is the input power. t is the operating time. E is the energy used. c is the unit price per kWh, the tariff. C is the cost.
Energy is power times time. Cost is energy times the price per unit. Internally the calculator works in joules and converts the tariff to match, then shows kWh and pounds.
Sense check: 24 kW for 2 hours uses 48 kWh. At 7 p/kWh that costs £3.36. Double the run time and the cost doubles.
Watch out: use the actual input power, not the useful output. Standing charges are not included.
Enter your values to see the result.
Good to know
Use actual input power or metered energy. Standing charges and other fees are excluded.
Sources
Results are arithmetic only. Worked examples are not recommended design settings. This library does not provide automatic gas pipe selection, live gas tightness tests, purging procedures, combustion acceptance limits, installation approval or commissioning certification. Manufacturer data and the applicable current method remain essential.