What it costs: water softening | Features

Domestic hard water treatment and conditioning systems	Capital cost £/unit	Net present value for 60 years £/m²	Service lives years
Ion exchange water softeners
Water softener up to 5 persons; 1500 litre capacity; timer controlled	590	2,440	10-20
Water softener up to 5 persons; 1500 litre capacity; water volume controlled	667	2,610	10-20
Water softener up to 8 persons, up to 2,000 litre capacity. Computer controlled to predict usage pattern with diagnostics	964	3,230	10-20
Physical water conditioners
In-line magnetic physical water conditioner; flow rate to 25 l/min for individual appliance	135	1,700	3-10
Electrolytic physical water conditioner; based on zinc, variable flow rate; mains powered	494	2,090	5-10
Electrolytic physical water conditioner; based on zinc; basic system	171	1,420	5-10
Electronic (modulating frequency) physical water conditioner for combi systems; mains powered	216	1,610	5-10
Table notes
Capacity based on water hardness of 300 mg/l (parts per million) calcium carbonate (CaCO3) equivalence. A discount rate of 3.5% is used to calculate net present values.
Costs are based on averages from sample of systems available on the market with generic allowances for installation and maintenance. Service lives are based on the average of the range. Regular inspection and servicing account for the bulk of the through life cost. Direct comparison of options may not be possible as they relate to different functional solutions. A whole-life cost analysis based on project-specific information is essential for a realistic best value appraisal.