The UK could significantly cut consumer energy bills and reduce its carbon emissions and gas demand using the Dutch ‘Energiesprong’ (energy leap) approach to retrofitting homes, according to a new study by think tank Green Alliance. 
Over 2017-18, England and Wales experienced an estimated 50,000 excess winter deaths, a figure not seen in over four decades. The UK has one of the least energy efficient housing stocks in Europe and, with no clear policy pathway, it also faces a significant challenge in switching away from fossil fuel sources of home heating, a major contributor to greenhouse gas emissions.
The government’s approach to retrofitting homes to date has been incremental and expensive, with the last major effort to address it, the Green Deal, closing in 2015 after only two years, having failed at great cost to achieve its aims.
Unlike former methods, the Energiesprong approach is less invasive and is aesthetically pleasing to residents. It involves fitting a highly thermally efficient external façade to an existing building, and simultaneously installing a heat pump, solar panels and even batteries where they are cost effective.
At least 11 million homes in the UK are suitable for this approach, and retrofitting them could bring energy bills down drastically for householders and reduce UK carbon emissions by 37 million tonnes overall, equivalent to removing 17 million cars off the UK’s streets. The homes also retain heat well and have the capacity to store electricity, potentially reducing demand for gas at peak times by 40 per cent.
This approach has been successfully deployed in the Netherlands where over 1,300 net zero energy refurbishments have so far been carried out, with over 14,000 in the pipeline.  In the UK it has been piloted in Sneinton, Nottingham, where ten 1960s homes were given Energiesprong retrofits in 2017. Householders’ energy bills were subsequently cut by up to 60 per cent and property values rose by an estimated 25 per cent.
To test the potential and viability of the model for wider application in the UK, the report recommends that the government should adopt a ‘commit and review’ approach, where 5,000 suitable homes are retrofitted using the Energiesprong approach, supported by innovation funding.
The funding commitment necessary, £120 million, should be conditional on the industry bringing the cost of an Energiesprong retrofit down from its current high of £75,000 per home to £35,000, through economies of scale and industry development. At this point, the analysis shows, no further subsidy would be necessary to roll out a large scale, transformative retrofit programme across the country.
The report is funded by the Zero Energy Building Catalyst programme supported by the European Regional Development Fund. The programme is led by Devon County Council and will see 15 Energiesprong retrofits demonstrated in the county as well as work to develop the local supply chain.
Devon county councillor, Roger Croad said: “The Energiesprong retrofit is a one-step approach that could turn our inefficient housing stock into net zero energy homes. Through product innovation, cost effective off-site construction and rapid retrofitting, Energiesprong improves on all the shortcomings of the methods currently tried. It could energise a stagnant industry and transform home energy efficiency for many more people in the UK.”
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 Reinventing retrofit: how to scale up home energy efficiency in the UK, Green Alliance, February 2019
 Excess winter mortality in England and Wales, Office of National Statistics, 2018
 Energiesprong Netherlands.