Question to the Department for Business, Energy and Industrial Strategy:

To ask the Secretary of State for Business, Energy and Industrial Strategy, what assessment his Department has made of the number of properties that have sufficient space available for the installation of a water tank in addition to fitting a new heating system.

We do not currently hold data on how many homes have sufficient space available for the installation of a water tank in addition to fitting a new heating system. However, the English Housing Survey suggests the proportion of dwellings that have central heating and a separate hot water cylinder has decreased from half of the stock in 2008 to just over a third in 2018. This suggests a general attrition in the space provision for separate hot water cylinders.

As low carbon heating systems generally require a separate hot water tank, we are exploring this further through projects like the Government-funded Electrification of Heat Demonstration Project and working with industry to develop solutions to internal space constraints, such as providing innovation funding to support the commercialisation of technologies like thermal phase change batteries, which occupy a third of the space of a traditional hot water cylinder for the same hot water output.