Energy has left the building: but how much?

One of the biggest obstacles in taking on the UK housing stock’s leakiness is the lack of robust data on the minutiae of what the effects of doing the energy efficiency stuff actually are. But things are changing.

Last year, the Energy Saving Trust and Communities and Local Government (CLG) funded a programme to test the energy efficiency of four new-build homes some time after their construction.

The results were good. Three out of the four properties exceeded the targets that were needed at the time of their planning approval. There was still a whole-house heat loss at an average of 14 per cent higher than designed. A small gap, but a gap nevertheless. Another study, in 2008, showed a performance gap of an alarming 60 per cent.

This data is crucial to the UK’s attempts to meet carbon reduction targets, and it also pinpoints areas that drain a household of cash.  If heat is lost through the fabric of a house, then people will turn up their thermostats, and boilers will be switched on for longer. When the bills drop through the door the excitement of moving into a new home can be quickly dampened.

The homes that we tested are a start – but there’s more to be done, that’s for sure. The Good Homes Alliance is now calling on the government to encourage the construction industry to test samples of all new homes. They would also like to see a feedback mechanism so that lessons can be learned and acted upon by builders and suppliers.

Data has to be accurate and credible, while modelling and calculation tools also have to be periodically and systematically reviewed. The industry standard tool is the Standard Assessment Procedure, or SAP, developed by BRE for the Department of Energy and Climate Change.

To simplify a fairly complex story, it assesses a new-build’s compliance with part L of building regulations in England and Wales (and the equivalent in Scotland and Northern Ireland), acts as a basis for Energy Performance Certificates, and forms the basis of other tools, such as the Energy Saving Trust’s Home Energy Check

But on this front, change is a afoot too. A consultation on SAP is taking place just now, which will take a look at such things as the carbon dioxide emissions factors, changes to the use of regional weather data to help to calculate running costs, the means of assessing hot water, the treatment of water loss and setting standard values for heat pumps. 

By continually collecting, assessing and improving data, tools and calculators such as these, we can keep an eye on how to improve the UK’s carbon reduction targets and help householders to save a few bob on bills.

Of course, the fabric of a building is only part of the story. The way a householder uses heat, insulation and water is just as crucial. GHA is gathering feedback from homeowners to see the impact of their behaviour on energy performance.

Smart meters will also help us to keep an eye on real-time energy use. And of course, our advice service is only a call away if you want to check your own home energy behaviour.