Regulations concerning the environmental impact of appliances are increasingly stringent and no commercial domestic water heaters were able to meet them. Now, EU-funded scientists have delivered a winner.

In its commitment to reduce its environmental impact, the EU is implementing mandatory energy labelling for many appliances, including domestic electrical storage water heaters (DESWHs). When mandatory eco-design energy labelling comes into force, only DESWHs in energy classes A and B will be allowed on the market. Currently, no commercially available DESWH meets those requirements.

Scientists initiated the EU-funded project EcoWaterHeater to develop a new design with the best life-cycle cost and the smallest environmental impact among all other European water heaters. They focused on two key areas: improved insulation for reduced heat loss and intelligent temperature control. In addition, to offset increased production costs, researchers investigated a new weld-less manufacturing process for the inner tanks. The method uses less material and avoids the costly and energy-consuming welding process typically required.

The aerogel insulation material and its unique application improves insulation around fittings. The user-friendly control system facilitates a two-tariff system taking advantage of heating water in off-peak power grid periods through intelligent temperature control. The improved insulation and temperature-control system reduced standing heat loss by more than 40 % and by an additional 7–12 %, respectively, in the prototype system. The weld-less tank system not only reduces production costs due to less material and no welding, it also reduces corrosion to increase lifetime and thereby reduces life-cycle costs.

The ECOWATERHEATER Project has the potential to make a significant contribution to sustainable hot water production through the reduction of material usage and heat loss, both of which will contribute to increased economic benefits for manufacturers and consumers. In addition, the design will put the businesses involved in a market leadership position given the lack of comparable technology able to meet increasingly strict regulations.