Electric Shower Running Cost Calculator
Convert the unit’s rated electrical input and household shower time into energy and electricity cost. Water flow, inlet temperature, pressure and water charges are outside this calculation.
Quick answerAn 8.5 kW electric shower used for eight minutes consumes about 1.13 kWh and costs $0.19 per shower at $0.17/kWh. Two showers/day use about 827.3 kWh and cost $140.65 per year, or $11.72 per average calendar month.
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How it works
Energy per shower = rated kW × minutes ÷ 60. Annual energy = energy per shower × showers/day × 365. Cost = kWh × electricity rate; average monthly cost divides the annual total by 12.
Electric-shower energy examples
Every row assumes one shower/day and $0.17/kWh. The result covers electricity only, not water or wastewater charges.
| Rated input and time | Energy per shower | Cost per shower | Annual cost |
|---|---|---|---|
| 7.5 kW × 5 min | 0.63 kWh | $0.11 | $38.78 |
| 8.5 kW × 5 min | 0.71 kWh | $0.12 | $43.95 |
| 8.5 kW × 8 min | 1.13 kWh | $0.19 | $70.32 |
| 9.5 kW × 8 min | 1.27 kWh | $0.22 | $78.59 |
| 9.5 kW × 10 min | 1.58 kWh | $0.27 | $98.27 |
| 10.5 kW × 10 min | 1.75 kWh | $0.30 | $108.59 |
Do not use this cost table to select a shower rating, cable, protective device or water connection. Installation and replacement require the exact manufacturer instructions and qualified electrical/plumbing assessment.
Worked example: an 8.5 kW shower for eight minutes
Eight minutes is 8 ÷ 60 = 0.1333 hours. Multiply by 8.5 kW to get 1.1333 kWh per shower. At $0.17/kWh, the unrounded cost is $0.1927, displayed as $0.19.
At two showers/day for 365 days, annual energy is 827.33 kWh and annual electricity cost is $140.65. Average monthly cost is the annual total divided by 12, not an assumption that every month has the same number of showers.
Rated kW is electrical input, not water flow
The calculation needs the exact electrical rating and the time energized. Water flow, inlet-water temperature, selected temperature and pressure affect the shower experience and whether the unit can reach the requested outlet temperature; they are not interchangeable with electrical kW.
Triton’s installation instructions show that shower ratings and supply requirements are model-specific. Do not choose a lower- or higher-power replacement from running cost alone.
Shorter time is the direct modelled saving
At the same rated kW, cutting shower time cuts electricity in direct proportion. For the 8.5 kW example, reducing eight minutes to five reduces energy from about 1.13 kWh to 0.71 kWh per shower.
Energy Saving Trust recommends spending less time in the shower as a practical energy-saving step. Any change must still preserve safe washing, temperature and accessibility needs.
What this calculator deliberately excludes
This page does not estimate water consumption, water price, wastewater charges, household hot-water storage losses or comparison with a bath or another heating system. Those require actual flow and system data.
An electric shower is hard-wired high-power equipment in a wet location. Do not put it through a plug-in energy monitor or attempt electrical measurement, installation or replacement without the required qualifications and manufacturer instructions.
Sources used for assumptions: Triton — electric-shower installation and operating instructions; Energy Saving Trust — shorter-shower energy-saving guidance; U.S. Energy Information Administration — watts, watt-hours and kilowatt-hours.
Frequently asked questions
How much electricity does an 8.5 kW electric shower use?
Multiply 8.5 kW by shower minutes ÷ 60. Five minutes uses about 0.71 kWh; eight minutes uses about 1.13 kWh.
How much does an electric shower cost per shower?
Multiply kWh per shower by your electricity rate. An 8.5 kW shower for eight minutes costs about $0.19 at $0.17/kWh.
Does electric-shower cost depend on water flow?
This electricity-only formula uses rated kW and energized time. Flow and inlet temperature affect water delivery and comfort, so they matter for system performance but are not inputs to this simple electrical calculation.
Can I reduce cost by installing a lower-kW shower?
Do not choose or alter equipment from cost alone. Shower output, water conditions, electrical supply and installation requirements are model-specific; use manufacturer guidance and qualified installers.
How can I reduce electric-shower electricity use?
At the same rating, reduce the minutes energized. Energy Saving Trust recommends spending less time in the shower as a practical energy-saving step.
Does this include water charges?
No. Add actual flow in litres or gallons per minute, local water and wastewater tariffs and any fixed-charge rules separately.
Can I measure an electric shower with a plug-in meter?
No. An electric shower is hard-wired high-power equipment in a wet location. Use the exact model rating and qualified electrical guidance; never insert a plug-in meter.
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