Actual costs and 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, Methven UK accepts no liability with regards to the level of savings that are actually achieved.

Flow rates

The water savings calculator is based on comparing ‘the selected handset’ flow rate against an average flow rate of 15 lpm.

• Developers Part G calculation savings are based on comparing a standard needle jet handset of 15 lpm to our Kiri Low flow handset which has a 5.5 lpm flow rate.
• Homeowners calculation savings are based on comparing a standard needle jet handset of 15 lpm to our Aurajet Aio handset which has a 8 lpm flow rate.
• Shower heads are tested at a working pressure of 3.0 bar.

Energy usage

we assume the hot water is supplied by an A-rated gas combi boiler. We have used boiler efficiency data for the most efficient combi boilers as listed by Home Heating Guide and have assumed that the connecting pipework between the boiler and the shower is well insulated.

• Boiler efficiency set at 85% (range = 70% - 92%)

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 October 2022.

Gas:

• Supply: 8p per kWh

Water bills estimate

Data published by United Utilities - What does a litre or cubic metre of water cost? Assumes metered water connection.

Water supply:

• Rate: £3.08 per m3

Carbon footprint

Relevant emissions factors extracted from - How much CO2 does a tree absorb? by VIESMANN.

• C02E per kWh of heat from a gas boiler - 0.21kg

Energy savings Calculation

Assumptions have been made about shower usage in the home in order to provide and accurate depiction.

• We have assumed the shower outlet temperature is set at 40°C .
• We have assumed the inlet temperature is set at 10°C cold and 60°C hot.
• Energy needed to heat 1ltr from 10°C cold to 60°C based on inlet/outlet temperature - 209300 Joules.
• Calculations are based on the assumption that the occupancy is 2.4 (UK average). Taken from ONS 2020 census data.
• We have assumed the length of a shower is 6.633 minutes. Taken from Water Efficiency Conference 2015 by Hendrickx et al.
• More than half of British homeowners shower at least once per day. Three quarters of Brits shower too much | YouGov