Some buildings are beyond saving, such as a south Dublin cottage which had to be knocked to deliver the first phase of a sleek new low energy home.

This upgrade and extension to a rural home in County Cork cut its energy use by almost 90%, bringing it to the cusp of an A1 Building Energy Rating.

In the absence of strong energy requirements under building regulations, much of the UK’s new build innovation has been driven by the Code for Sustainable Homes. Amid growing concern that the code’s attention to energy efficiency falls some way short of passive house, monitoring results from one social housing scheme offer a rare opportunity for direct comparison.