Green Deal: report reveals reality of home energy savings

However many energy-efficient new homes are built in the UK by 2050, nearly 80 per cent of the homes we live in now will still exist – and we are legally obliged to cut carbon dioxide by 80 per cent before then.

The UK faces a huge challenge to retrofit its housing stock, i.e. modify existing buildings to current standards. We need to invest heavily in the homes we see around us.

The recent ‘solar boom’, triggered by a Government incentive to financially reward individuals who install renewable energy technologies, has seen thousands of solar panels installed on roofs across the UK. 

This could be seen as progress towards meeting the carbon targets, but many of these installations are on buildings where there is no insulation in the loft or cavity walls. The good news is that the incentives have changed so they are linked to the installation of some of these more basic measures, but that won’t apply retrospectively to the homes that joined in the solar boom.

How can savings be made?

Measures must be installed in the correct sequence to achieve the greatest savings. A report published today by JRF, in partnership with JRHT, highlights the reality of retrofitting a typical 1930s semi-detached property (representative of a good proportion of the UK housing stock).

It shows that by sequencing the installation of retrofit measures, it is possible to achieve the challenging targets on existing stock – but it costs a lot of money, and what it does in reality is different to what it does on paper: 

• the modelling tools used to calculate carbon savings and performance were inaccurate;

• measures that were installed performed significantly worse in situ than in test lab conditions;

• those same measures were not installed correctly. 

The measures that we’re talking about are not complex renewable technologies, but loft and cavity wall insulation, the bread and butter of energy improvements, which have been installed in the UK for the past 20–30 years. 

The research also uncovered failings to achieve design performance in some of the more advanced measures, including triple-glazed windows, external wall insulation and under-floor insulation.  

In total, the improvements made to the fabric of the home only produced about 70 per cent of what the project set out to achieve, but nevertheless improved the carbon footprint of the property by 66 per cent.

The concern is that missing 30 per cent. If such a large discrepancy can exist on a ‘flagship’ project like this, then what kind of discrepancies could exist when these measures are rolled out in volume, as they have been in the past, and as the Government is hoping they will in the future?

The future is the Green Deal, the new Government policy that Greg Barker, Climate Change Minister, has described as “the biggest home improvement programme since the Second World War, shifting our dated, draughty homes from the past into the future, so it’s vital people can trust it”. 

Yet recent BSI research shows that only one in five consumers would consider using the Green Deal to improve their home, as they are unsure about it. If the Green Deal really wants to reach out to the consumer, then this issue of ‘trust’ is key. 

The Green Deal will be hard to sell – and that 2050 target will be even harder to achieve – while there is the risk that Green Deal consumers will only achieve 70 per cent of the savings they hope for by improving their home.