Groundbreaking housing retrofit pilot ‘shows actual data should inform works’

Tom Johnson and Siobhan Cross of Pinsent Masons, and entrepreneur Joseph Michael Daniels, co-founder of property tech business Senze, were commenting after a report was published into the piloting of Senze technology in 121 homes owned by Bromford housing association.

In the pilot, commissioned by Lloyd’s, Senze’s approach of using real-time data to measure the thermal performance of homes so as to inform “targeted interventions” was tested against an EPC-led approach, where the thermal performance of a property is determined on the basis of modelled data and retrofit solutions proposed on the basis of that modelled data.

Daniels told Pinsent Masons that the company deploys proprietary digital scans – or twins – using light detection and ranging (LIDAR) and installs room sensors to monitor data on air pressure, temperature and relative humidity as well as energy consumption in individual rooms within a property, and meters to provide live energy data. Using an algorithm based on a non-invasive “in-use” measurement to measure heat loss and transfer, the company can then pinpoint where changes could be applied to help address heat loss or improve ventilation. The result, he said, is better regulated environments within homes and lower energy bills for occupiers.

This approach, said Daniels, is an alternative to the co-heating standard which, if applied in practice, requires a property to be vacant for 1-3 weeks during which it is heated to high temperatures, and can cost between £10,000 - £15,000 per property to apply.

The headline EPC metric is expressed as an A to G rating. Current domestic EPC ratings are based on energy efficiency derived from modelled energy costs. Under UK government proposals, owners of social housing would need to achieve an EPC C rating, in line with reformed metrics, by 2030, with proposed transition provisions allowing compliance via a current form EPC C rating obtained before 31 March 2028. The report on the pilot highlighted how around 1.2 million assets in the social housing sector in England and Wales are currently thought to fall below the EPC C standard.

The Bromford pilot was focused on 121 homes, of which 59% were considered to require retrofitting works to achieve both the modelled and measured EPC C standard. In the case of those properties, the pilot identified scope for Bromford to achieve savings of £27,872 per property if it were to carry out a data-led and more targeted approach, compared to actioning retrofit works informed by modelled data and EPC metrics. Senze’s measurement and analysis methods have been verified by academics at Birmingham City University and Salford University.

Johnson said: “The findings from this pilot are extremely compelling. They offer an insight into the power that data and technology can offer in shaping retrofit programmes across large scale housing portfolios, and the potential material savings and operational efficiencies that can be achieved as a result.”

“Notwithstanding the pilot is based on a small sample size, a basic extrapolation of the figures here shows that, for housing associations on the cusp of a major retrofit exercise for achieving compliance with EPC C, there is potential to reduce by billions of pounds the national bill if a measured data and targeted intervention approach is embraced at scale across social housing stock and recognised in EPC methodology. At a time when there are severe constraints on housing association budgets, this pilot is likely to be viewed by the industry as potentially transformative for achieving cost-effective compliance with emerging environmental standards. It is also likely to impact positively on financing for ongoing maintenance as smart retrofit measures have the potential to reduce/mitigate operational risks,” he said.

Despite the findings from the pilot, Daniels acknowledged that there are challenges for Senze in persuading portfolio owners to adopt a measured data approach to improving the energy performance of their assets.

Daniels said: “There is an economic, social and environmental case for using actual data to drive targeted retrofit interventions, as this pilot has shown, but the policy framework is flawed in that the EPC metrics that prevail – and the PAS2035 standards upon which government grants are dependent – do not map neatly to the actual data. For example, the EPC metrics will not always credit data-driven targeted interventions with an improved EPC rating.”

Cross said: “The current EPC rating system is based on modelled energy costs based on standardised heating, temperature and fuel price assumptions and modelled performance of building features. The government’s proposed domestic EPC reforms envisage EPCs with multiple ratings covering a building’s fabric performance, heating system type, smart readiness, and energy cost – but none of the proposed new metrics envisage using actual measured data for EPC rating purposes. The results of this pilot suggest a rethink should be considered for fabric performance”.

In its December 2024 consultation on EPC reforms the government sought views on incorporating data from “smart meter enabled thermal efficiency ratings” products into the energy performance assessment framework, and said it intended to run a pilot on this and consider assurance issues before the possible introduction of this. Cross said: “This should be progressed urgently to improve EPC quality; avoid unnecessary works and their costs and embodied carbon emissions; and avoid any trade-offs involved in smart measured data based retrofit works and MEES compliance”.

Daniels said an EPC-led approach to retrofitting properties might achieve “tick-box” compliance but can often either fail to address fundamental problems of heat loss – and, in turn, fails to support cheaper energy bills for occupiers – or result in over-insulation of properties with inadequate ventilation and the creation of “sick buildings”. These, he said, “are not the outcomes of well-functioning environmental policy”, and he cited how it can have health implications for residents and legal risk implications for asset owners.

Daniels said: “While our measured data approach can help deliver better targeted retrofit programmes which deliver cheaper energy bills for more occupiers, some additional works may be required to achieve tick-box compliance with EPC requirements. In that context, it is perhaps understandable that asset owners might consider it best to focus on an approach that directly links to EPC compliance and conforms to PAS standards. However, if measured data on thermal performance of the property is incorporated into EPC and PAS compliance, landlords would be able to better address the actual problems and avoid carrying out unnecessary and costly works that may expose them to other legal risks”.

“For instance, there is a real risk that applying retrofitting measures, like wall insulation or new windows, to a property without using actual measured data to understand what effect those changes will have could result in over-insulation and poor-quality ventilation and create the conditions for moisture and mould to develop, which poses a health risk to occupiers,” he said.

Johnson said the problem of ‘sick buildings’ is a pertinent one for landlords to consider given the responsibilities they could face under the upcoming Hazards in Social Housing (Prescribed Requirements) (England) Regulations 2025, known as Awaab’s Law.  

“Awaab’s Law sets out timeframes within which landlords must carry out repairs upon becoming aware of potential serious hazards,” Johnson said. “The law, due to be phased in for social housing in England, starting on 27 October, was driven by the family of Awaab Ishak, a child who tragically died after exposure to mould in a social home his family rented in Rochdale.”

“While Awaab’s Law will only apply initially to the social housing sector, the Renters’ Rights Bill, currently in the final stages of the UK parliamentary process, provides for Awaab’s Law to be extended to the private rented sector in due course. Implementation of Awaab’s Law in the private rented sector in Scotland – from March 2026, subject to parliamentary approval – is also envisaged under the recently passed Housing (Scotland) Bill,” he added.

Daniels, who has built housing using smart data principles and technologies in a number of locations globally, said taking a measured data approach to retrofit programmes is akin to taking out “an insurance policy” against the risk of health-related claims and future changes in environmental policy.