Changeworks and Hjaltland Housing Association: Deep retrofit

Changeworks recently supported Hjaltland Housing Association to assess the outcomes of its deep retrofit pilot project. Changeworks’ evaluation of the results will help influence the wider rollout of decarbonisation measures across their properties.

Hjaltland Housing Association is aiming to go beyond the current statutory requirements (EESSH2) for decarbonisation of their housing stock. The housing association is opting to pursue a programme of “deep retrofit” to create truly low-carbon, warm homes which benefit its tenants.

To lay the groundwork, Hjaltland ran a pilot project across five of their properties in Virkie, Shetland. Changeworks’ Impact Evaluation team was appointed to assess the outcomes for both the housing association and their tenants.

What did the project involve?

Five properties received different energy efficiency retrofits. Three retrofits followed a fabric first approach, i.e. improving the insulation of the property. Renewable technologies were installed in the remaining properties. One property received solar panels, whilst the other received an air source heat pump.

What were the results of the project?

Changeworks’ Impact Evaluation team reviewed quantitative data collected from energy monitors and environmental sensors that Hjaltland had installed in the retrofitted properties. Additionally, Changeworks gathered qualitative data through interviews with tenants.

The Changeworks team determined that:

1. All properties showed a reduction in energy demand and carbon emissions, with no negative impact on tenant comfort.
2. Fabric first retrofit achieved an average energy demand reduction of 33%.
3. Installation of an air source heat pump reduced energy demand by 35%.
4. Solar panels generated enough electricity to meet around 15% of energy demand.
5. Mechanical Ventilation Heat and Recovery (MVHR) improved air quality in the fabric first properties.

Despite the clear positive impact on energy demand reduction, none of the properties achieved EESSH2 standards. This is due to the reliance of EESSH2 on Energy Performance Certificate (EPC) Ratings and the limitations of the underlying calculation software in accurately accounting for MVHR.

In contrast, it is anticipated that all of the properties (except the solar PV property) would meet the Social Housing Net Zero Standard (SHNZS), which is set to replace EESSH2.

Going forward

The Impact Evaluation team’s findings have provided Hjaltland with an evidence-based understanding of how different energy efficiency measures impact demand reduction and tenant comfort.

Paul Leask, Head of Investment and Asset Management at Hjaltland, said “this report confirms the higher performance of a fabric first approach, when you factor in the lifecycle costings, and will assist us in accessing further funding for insulation improvements. The project was supported by the Energy Redress Carbon Emissions Reduction Fund and has enabled us to get the detailed analysis from Changeworks which is invaluable in setting our energy improvement strategy going forward.”

If you would like to find out how Changeworks can help with your decarbonisation strategy, please contact us on workwithus@changeworks.org.uk