The system used to calculate energy savings under the Green Deal, which is critical to the flagship energy efficiency programme’s success, is unreliable and inflates the savings a householder can expect to achieve from retrofit work to their home by as much as 77%, a study for social housing provider Affinity Sutton has found.
The study monitored the effect of retrofit work carried out by contractor Keepmoat on 102 homes over the course of a year, while the data was analysed by consultants Verco, Baily Garner and Parity Projects. They found that the SAP model, which is used to calculate building performance, on average predicted that tenants would save 77% more on their energy bills than they actually did.
The report states that ‘FutureFit has found that SAP is not an accurate modeling tool for existing homes. Some steps have been taken to combat this inaccuracy in the Green Deal assessment process. But these are unlikely to fully resolve the issue. This makes the Green Deal a lottery for our residents. A few may benefit, and even fewer may do even better than expected, but the majority are likely to lose out with energy savings less than the annual Green Deal payments’.
Key finding include:
SAP is well established as the energy modelling tool for new build properties. It is now also the central tool in the Green Deal assessment process to predict what savings can be made in a home from energy efficiency improvements. Assessing how properties fared against the predictions of this model was an important part of the process.
• The SAP model used in FutureFit over-predicted the savings by an average of 77%:
– Average saving in gas heated properties was £49 a year.
– Average SAP modelled savings in gas heated properties was £217 a year.
Difference: 77% less than predicted.
• The overall difference ranged from over-predicting by £759 and under-predicting by £367.
• For gas savings alone, the difference was lower, but still significant, at 53%.
• Despite the potential mitigating impact of the Occupancy Assessment, this scale of variance suggests the ‘golden rule’ calculation the Green Deal rests upon is not entirely reliable, even when SAP model updates and the Government’s in-use factors have been applied.
• If a weighted average is applied across Affinity Sutton stock in terms of electrically heated properties to gas heated properties, 61% of our homes would save on their bills, but only 24% would realise predicted SAP savings.
• This suggests that only one in four Affinity Sutton properties would be likely to benefit from the Green Deal.
Affinity Sutton writes:
Leading affordable housing association Affinity Sutton launched the final findings of FutureFit, its pioneering retrofit project.
FutureFit is helping Affinity Sutton develop an informed, well-formulated policy on energy efficiency in existing homes, to reduce fuel poverty and inform the wider debate on carbon targets.
The project found that although there are challenges in tracking energy use, retrofitting does result in savings, particularly when following a fabric first approach. As a result we are developing an Energy Efficiency Standard to apply to all our homes by 2020.
The findings also show that:
· Resident engagement is critical, particularly around electricity usage – as a result we are updating our energy lifestyle advice programme – EnergyFit.
· We are unable to support the Green Deal as it currently stands but are keen to continue to work with Government so that the Green Deal can fulfil the savings necessary for social housing.
· Our results support the need for the Affordable Warmth element of the Energy Company Obligation (ECO) funding to be available to social households.
· As well as retrofitting our properties we also need to engage with everyone involved in the process, from the supply chain through to residents.
· The social housing sector must respond to the findings of this report – looking at how retrofitting can be funded and made to work, reducing carbon emissions and energy costs for some of the poorest in society.
Keith Exford, Affinity Sutton CEO, commented: ‘The FutureFit project demonstrates how the social housing sector is well positioned to deliver wide-scale retrofit. Although the results make it clear why Affinity Sutton is not currently supporting the Green Deal in our homes, this report sets out why it is so important to find a way to make it work for the very people who need it most.’
‘The social housing sector must respond to the issues raised and look to how retrofitting can be funded and made to work, reducing carbon emissions and energy costs for some of the poorest in society is a priority for us all.’
FutureFit provided a detailed insight into the retrofit agenda through working with 150 properties of drawn from 22 common types of housing – carrying out different packages of work and lifestyle advice along with installing monitoring equipment to track energy use and bills.
Affinity Sutton News Articles: LINK and LINK
For the data analysis see: LINK
For the futurefit report see: LINK
