A central pillar of the Optimised Retrofit project is to improve how buildings are assessed. This not only helps to ensure that investment in retrofit is well targeted but of course also feeds into the onward detailed design and specification of an appropriate retrofit upgrade package. Such assessment concerns two primary elements; the physical properties of the dwelling(s) and the occupant(s) and their energy use behaviours.

Traditionally the physical assessment of a dwelling has largely been considered as taken care of in the form of an Energy Assessor carrying out an rdSAP survey and producing an Energy Performance Certificate (EPC). Although quick and low cost, an EPC relies heavily on a number of critical performance assumptions being made based on what the assessor deems the age of the property to be. This often makes large swathes of properties look very similar in energy performance terms when in reality we know that no two properties are ever the same, even before factoring occupant behaviours or variations in weather conditions.

The answer to improving physical property assessments of course lies in finding ways of actually measuring the true unique real world performance of buildings at scale. Ordinarily, building performance measurement is considered high cost, complex and disruptive. In order to challenge this and assess viability, the Optimised Retrofit project team commissioned Build Test Solutions to showcase what is possible today by carrying out a series of groundbreaking measurements on 5x properties owned and managed by Linc Cymru.

These included measurement of the overall thermal performance of the building fabric, an assessment of mould and condensation risk exposure across key rooms in the home, air leakage testing and also rapid measurement of wall U-values.



A full case study write up detailing the works undertaken and key lessons learnt can be found here.

Key insights from just this early work include:

  • Real world performance can be significantly different from what is predicted by modelling tools, including EPCs. For retrofits, the performance is often better than predicted and this can lead to needing to recalibrate design specifications and expected outcomes.
  • Although measurement methods that are quick, low cost and non-invasive exist, measurements must typically be carried out during winter months, requiring careful planning, especially where pre and post works measurements are sought.
  • Whole house energy assessments can be further enhanced by inputting directly measured performance parameters, reducing the level of assumptions in our models.
  • Relying solely on visual surveys, design expectations and predicted performance introduces a significant risk of unintended consequences and unexpected performance. Performance measurement provides a method to understand and mitigate this risk.



Luke Smith, Managing Director of Build Test Solutions, said:
“Whilst in many ways it can be pretty clear which properties are most in need of retrofitting; measurement of true performance not only helps to confirm any investment decisions but can also inform retrofit design specifications whilst also providing a baseline from which outcomes can be validated and quality assurance carried out. Saving energy, reducing fuel bills and improving comfort is not like kitchen and bathroom replacement programmes where a visual inspection is all that’s needed. The upgrades are covered up, hard to inspect and the devil is truly in the details.

Measurement has traditionally been considered the preserve of a handful of Universities and researchers, affordable only on a very small scale. Technology is moving apace and it really musn’t be if we’re taking the net zero objective seriously. Here at Build Test Solutions we’ve developed a whole host of extremely powerful yet simple and low cost methods and I’d encourage you to get in touch to see how we and our partners could help unlock a whole new level of value from your assets and energy efficiency upgrade investments.”

With the winter season fast approaching, all Optimised Retrofit partners (and the sector at large!) are encouraged to begin considering the value of real world performance measurement across your own portfolios and how this might support not only the targeting of investment but also as a means of informing design decisions, assessing impacts and validating outcomes.

For further information contact Optimised Retrofit project partners Build Test Solutions direct via enquiries@buildtestsolutions.com.