When David Partridge, the chair of the Net Zero Carbon Building Standard, discovered that a gas boiler needed replacing in a flat that he rented out, a like-for-like replacement was not an option. “I was about to publish a standard that insists on no fossil fuels. So, if I am seen to be doing the wrong thing, that wouldn’t look good,” he recalls. 

“So, I thought, I’ll do what I am supposed to do by putting in an air source heat pump, batteries and a Sunamp [thermal storage] and all the wizzy bits and pieces.”

But these noble aspirations did not turn out as he hoped. “It was a complete disaster, the heat pump was far too big, and the batteries were fighting each and drawing down electricity when they shouldn’t have. The poor guy living there couldn’t afford his energy bills and I’m not sure if we saved any carbon – or I have ended up shoving loads more into the atmosphere.”