Saving water with point of use water heaters

A bare wire instantaneous water heater near outlets saves on water and energy and can take pre-heated water

Less water wastage; another reason to consider instant and point of use water heaters

You are probably familiar with the fact that point of use water heaters (and particularly instantaneous water heaters) are substantially more energy efficient than central stores of hot water. With the costs of energy skyrocketing, we’ve seen installers switching customers to these and claiming savings of £5 a day on energy bills.  

But there is another way in which decentralised hot water provision is more environmentally sustainable and helps to future proof homes. After a long hot summer and a major drought, we are all even more viscerally aware of the need to preserve water and the fact that a changing climate means UK residents can no longer make assumptions about endless, unrestricted supplied of water year round. Key to the government’s net Zero target for 2050 is a measure to encourage local authorities to adopt a tighter standard of 110 litres per person per day, compared with the current standard of 125 litres, for new homes where appropriate, requiring developers to install more efficient fixtures and fittings. With more and more homes, even among the legacy housing, stock  metered for their water and spiralling inflation making cost increases inevitable, this is a consideration that is hitting pockets as well as consciences. 

If you assume a fairly typical 15 metres run of pipe between a cylinder and an outlet in a family home, around 4.8 litres of water will run through cold before the hot water makes it to the tap. Even if the hot tap is only run 3-4 times a day nearly 20% of that 110 litre target could be run straight down the drain. Switching hot water provision to heaters situated next to outlets is essential if we are to hit targets for domestic water conservation. With units located directly above a sink the pipe run can effectively be reduced to almost zero with water running straight from a heater out of a tap fitted to the heater. Even with hidden undersink or shower installations where the unit supplies a standard tap or shower mixer we typically see pipe runs of less than 4 metres, cutting losses by two thirds or more.  

Our bare wire instantaneous water heaters have the advantage of being able to take pre-heated water which adds another option to save water. You can use them to prevent water wastage when, for example, adding a new shower room in an extension a long way from a boiler. The unit will come on and provide instant hot water and then gradually reduce how much work it does as hot water comes through the main supply.  This also adds useful redundancy to the hot water supply should the boiler ever be out of service. 

So, when you are thinking about hot water provision for your next project, even if you are planning a heat pump for heating, think carefully about choosing a decentralised option for hot water. Even if practical considerations make a store a necessity (perhaps to supply a bath where 3 phase electricity is not available to run a powerful 400 v instantaneous heater), it may well be worth the investment to supply some outlets with their own decentralised supply, particularly if they will be a long way from that central store.