Only 10 weeks and UK voters will make the most profound decision of this decade – will Britain stay or leave the European Union? There have been numerous analyses of what the implications of a so-called Brexit might be. Those include the economic impacts, security, and sovereignty.

In this blog I will discuss one specific area that would be significantly affected by Brexit but where an analysis is missing so far: energy efficiency. Historically, the EU had little influence on national energy efficiency but this has changed particularly in the last years. A number of important directives set EU-wide standards and targets for energy efficiency.

One of those directives is the Ecodesign Directive that requires manufacturers of electrical appliances to increase the energy efficiency of their products over time with increasing standards. This has had large benefits for households and businesses across Europe and also in the UK, even though outrage about bans of the least efficient vacuum cleaners have been making headlines in British tabloids for some time now. In case of products, Brexit is unlikely to substantially alter the status quo as product manufacturers importing their appliances to the UK market are likely to use EU requirements as a benchmark rather than producing a dedicated (low-efficiency) tranche of products for the UK market. Equally, UK manufacturers are likely to design their products according to EU norms so that they can export easily.

However, Brexit would have more profound implications in another area – buildings. New buildings need to meet energy efficiency standards set by the Energy Performance of Buildings Directive. In order not to lock in investments into inefficient buildings that require upgrading in the future it is crucial that all new buildings are built to a high efficiency performance level. Recent policy changes such as scrapping the zero carbon homes target show that buildings energy efficiency is not quite on top of the political agenda right now. Without a strong EU driver the future energy performance of new buildings is likely to be jeopardised.

Most significantly though Brexit would mean that the UK no longer needed to comply with the Energy Efficiency Directive which requires all Member States to set firm energy saving targets covering all sectors to reach the EU’s 20% energy efficiency target by 2020 (and subsequent targets thereafter). In particular, Article 7 of the Energy Efficiency Directive is a key provision that obliges Member States to calculate their own savings targets, and demonstrate how it will deliver the target between 2014 and 2020. If Britain exited the EU it would not longer be required to achieve those targets.

One could argue that the UK would simply replace EU legislation with national policies. However, recent policy changes in the UK do not instil a lot of confidence that there would be a strong national energy efficiency drive. As a result, progress would stall with little energy efficiency improvements in a country that still has one of the oldest and leakiest housing stocks in Europe. Whilst EU energy efficiency policy is by no means perfect, it plays an important role for achieving a long-term transition towards a more sustainable, modern and fairer energy system. The prospect of a Brexit in June this year is all but encouraging for the future of energy efficiency in Britain.