Policy Need to Knows

Is there a definition of what is termed as a block?

The guidance does not provide a definition of what constitutes a 'block'. This is a general term used to encompass terraces, low, mid and high rise buildings that include multiple dwellings.

Will we need to comply with BS40104?

It is in a consultation stage at the moment with a request to provide direct feedback or comment on it before 22nd September 2024. It is likely to be published during the delivery of Wave 3 and could therefore be a requirement for the later phases.

What are the impacts and expectation on the upcoming BS40104 Retrofit Assessment Standard Consultation, PAS 2035:2023 – particularly lodging ventilation requirements and potential impacts if SAP10 gets introduced mid-delivery?

There has been a recent update from DESNZ on RdSAP 10 for the WHSHF guidance (available here, p.17), which gives more clarification on how the introduction of RdSAP 10 will impact projects which are already using RdSAP 2012.

BS 40104, the British Standard for the retrofit assessment of dwellings, is due to be published in early 2025. The likely changes to the retrofit assessment of dwellings includes a more robust approach to the equipment being used, an increased focus on health and safety issues, a need to focus on the prediction of future climate change hazards, a more detailed analysis of ground conditions and topography together with exposure and shelter along with a much better ventilation assessment with occupancy analysis. This could add a little more time and cost to the assessment process and reporting but is also likely to increase or enhance the depth of recommended remedial works required before retrofit works can commence.

Can it be confirmed that RdSAP is an acceptable tool for modelling the baseline and potential energy efficiency of a home?

Additionally, the Social Housing Fund guidance states that the chosen methodology must be used consistently so that the Department can convert energy savings into carbon savings, using HMT Green Book guidance. Does this mean that lead applicants need to develop their own methodology and set of assumptions for carbon savings?

Energy savings must be based on modelling via the current SAP, RdSAP, or PHPP methodologies. The chosen methodology must be replicable, as the Lead Grant Recipient will be required to update their project energy savings during delivery to reflect any changes to the baselined information set out in their application form.

A clear documentation of key assumptions and methodology must be set out in their application form. DESNZ will convert the energy savings (kWh) into carbon savings (tCO2e) using the HMT Green Book guidance.

Is it possible to install Solar PV instead of external wall insulation on a solid wall home? External wall insulation does not provide a long-term cost-effective measure for this building type, whereas PV presents real savings to the residents and big SAP increases for a much smaller install cost.

The Warm Homes Fund requires that a fabric first approach is considered in line with value for money. If it can be demonstrated that the cost & energy savings from solar PV are more beneficial than external wall insulation, then that detail should be brought out in your application submission.