Energy and Water Savings Calculator - References

The calculator is designed to be informational and educational and the cost predictions / savings are illustrative of what you could incur annually. Actual costs / savings may vary from household to household depending on a number of factors, so although every effort has been made to provide an accurate depiction of the potential savings, Triton Showers accepts no liability with regards to the level of savings that are actually achieved.

Flow rates

When selecting a Mixer Shower we assume an average flow rates of 12l/min.

When selecting an Electric Shower we use the lab-measured flow rate of an 8.5kW unit at the target showering temperature, with a 12°C incoming cold water supply (considered to be the average temperature in domestic properties over the year).

Energy usage

When selecting a Mixer Shower we assume the hot water is supplied by an A-rated gas combi boiler. We have used boiler efficiency data for the top two most efficient combi boilers as listed by Which and have assumed that the connecting pipework between the boiler and the shower is well insulated.
When selecting an Electric Shower we have assumed an 8.5kW unit connected to a nominal 230V supply. We have ignored any power modulation that might occur if the unit is a thermostatic version and have used efficiency data derived from rigorous lab-tests on a number of models in our range (data that was used in the formal energy rating certification of these products).

Electricity and Gas bills estimate

Data published by The Energy Savings Trust for the average energy prices for England, Scotland and Wales following Ofgem’s Price Cap increase on 1st July 2023 - (last accessed 07-08-2023), as summarised below


  • Supply: 8.0p per kWh
  • Standing charge: £106.26 per year

Electricity (standard rate assumed):

  • Supply: 30.00p per kWh
  • Standing charge: £193.33 per year

Water bills estimate

Severn Trent Water, Schedule of charges 23/24 - 
Assumes metered water connection, Zone 1-8

Water supply:

  • Rate: 175.87p per m3
  • Standing charge: £34.06 per year

Wastewater / Sewerage:

  • Rate: 123.33p per m3
  • Standing charge: £23.30 per year

Carbon footprint

Relevant emissions factors extracted from “Government conversion factors for company reporting of greenhouse gas emissions”, published by DESNZ (last updated 28 June 2023)
Mileage equivalence estimation based on BEIS data for a VW golf (or equivalent)(UK)

Energy savings estimates

Gas (pans of rice cooked on a gas hob)
Gas hob performance characteristics - (Appliances Online, Technical specification for a BEKO gas hob 

  • Burner rating = 2.9kW
  • Main Ring ‘Max heat’ setting
  • Assumed setting used (70% of max heat)
  • Resultant Burner power output at assumed setting = 2.03kW
  • Assumed duration of each cooking session = 15 minutes
  • Resultant eEnergy used per cooking session = 0.51kW

Electricity (loads of washing dried using a tumble dryer)

Confused About Energy, Tumble drying article - 
Assumes each cycle uses 2.50 kWh of energy to dry an average load capacity of 4.75 kg