Shower Running Cost Calculator
Estimate the energy and metered water cost of a shower. Use the power rating for an electric shower, or model heated water from its flow, temperature and heating efficiency.
How to use Shower Running Cost Calculator
1. Choose the currency used for results. 2. Choose Electric shower for power-and-time costs. Choose Hot water when a boiler or other heater supplies the water, then enter the incoming and shower-water temperatures. 3. Change a value to update the results, or select Calculate. Review the chart and notes with the total. 4. Use Copy results, Share results or Download result graphic to keep the answer. Shared links include your figures. 5. Reset restores the editable example inputs.
Why use this tool?
An extra few minutes affects two costs: the energy used to heat the water and the amount of metered water consumed. Seeing them separately makes it easier to understand what a shorter shower changes. Electric showers and boiler-fed showers use different inputs. An electric shower’s power and duration estimate its electricity use. A hot-water model starts with the amount of water and the temperature rise, then allows for the heating efficiency you enter. Neither option adds the standing charge each time someone showers.
How the calculation works
Electric-shower energy = power in kW × minutes ÷ 60. Water volume = flow in litres per minute × minutes. In hot-water mode, useful heat in kWh = litres × temperature rise × 4.186 ÷ 3,600, assuming 1 kg of water per litre. Energy bought = useful heat ÷ (efficiency ÷ 100). Energy cost is energy bought × the unit price. Metered water cost is litres ÷ 1,000 × the combined volumetric water and sewerage price. The annual total multiplies cost per shower by average daily showers and days used. Fixed water and energy charges are excluded.
Example
A 6 kW electric shower used for ten minutes consumes 1 kWh. With an illustrative £0.25/kWh rate, 80 litres of water and a £3 charge per 1,000 litres, the shower costs £0.49: £0.25 for energy and £0.24 for water.
Practical tip
Use your measured flow if possible, and check whether your water bill has a volumetric sewerage charge as well as a water charge. An unmetered household will not save that calculated water amount directly on its bill.
Frequently asked questions
Which energy rate should I enter?
Use the electricity unit rate for an electric shower. In hot-water mode, use the price of the fuel supplying the heater, such as gas per kWh. A price in pence must be divided by 100 for a GBP input.
What does heating efficiency include?
Use an efficiency that represents the energy reaching the water. The model does not separately estimate pipe or storage losses, so include those in the assumption if you want them represented.
Are standing charges part of the cost per shower?
No. Those fixed charges are paid independently of a particular shower. The result compares usage-related costs from the inputs you provide.