Heat pumps may have been grabbing all the heat decarbonisation headlines lately but the heating industry has started making some noise about another potential player in the renewable heat revolution – the hot water cylinder.

Most households have removed their hot water cylinders to make way for combination boilers. In fact, the latest estimates suggest only around 9 million households still have a hot water cylinder.

So why are we potentially talking about turning back the clocks to protect the future?

Isaac Occhipinti, Director of External Affairs at the Hot Water Association (HWA), is one of those in the industry who believes hot water cylinders could become a vital energy storage tool as we move towards a Net Zero Britain.

The HWA is an advocate of energy storage and the role it can play in the systems of the future. It likes the concept to a home battery, with the hot water cylinder providing all the hot water needs of a home and also storing excess energy, ideally from renewable sources, in the form of hot water. The key to its success is the fact that it supports the grid by reducing the amount of generation needed to meet peak demand.

Rather than focusing on the fact that only around 45% of households have a hot water cylinder, the HWA states that the current capacity equates to 70GWh of untapped energy storage which it claims is around seven times the output of the UK’s largest pumped-storage hydroelectric facility, Dinorwig in Wales.

The HWA believes the predicted heat pump revolution will see this potential grow even further and is calling for greater collaboration across the heating sector to plan effectively for the future.

The calls for a hot water cylinder comeback are growing right across the industry. Neil Hope, Head of Technical at NIBE Energy Systems, said recently in an article for Installer Online, that “the re-installation of millions of hot water cylinders must be encouraged by the government.” He revealed that hot water cylinder training was being provided to installers with this future usage in mind.

Manufacturers, installers and low carbon energy experts are certainly looking seriously at the re-introduction of hot water cylinders as part of our battle against climate change. Consumers, however, may need to be persuaded.

Hope admitted that this would be challenging, since so many people have renovated their airing cupboards to create extra space, although he believes innovation in space saving solutions and new build regulations will alleviate this to some extent.

Perhaps one of the most appealing aspects of hot water storage, from the householder’s point of view, is that the shower won’t go cold just because someone else is running a tap.

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