We all know that our policies and programmes need more data of actual energy performance. Om an article on the Architecture Today website, Matthew Prowse, Specification and Housing Director for Knauf Insulation, discusses how homes being designed today can prepare for the imminent shift to measured ‘in-use’ energy performance.
Measured energy efficiency is coming, let’s design for it now
Energy efficiency is quickly becoming one of the most discussed topics in UK housebuilding – and for good reason. Factoring in both existing and new builds, UK homes collectively lose heat up to three times faster than their Western European neighbours, and improving this could ease the impact of both the climate emergency and the cost-of-living crisis.
A recent report from the Institute for Government highlights energy efficiency as a ‘major vulnerability’ in the UK’s struggle against rising energy bills and all eyes are on our new government to improve the situation. But naturally, the buck doesn’t stop there. The pressure to increase the energy efficiency of new-build homes ultimately falls on those who design and build them.
An energy-efficient design isn’t enough to generate real change. A home must perform as well in the real world as it does on paper, and we’re already starting to see this acknowledged in regulation.
Take this year’s updates to Part L of the Building Regulations for England; it includes a new BREL report that compares design-stage and as-built specifications. This indicates a shift in focus from notional designs to the performance of the finished product.
But a ‘finished’ home is only the beginning for homeowners. Once a home is occupied there is the potential to measure its in-use energy performance too. Energy Performance Certificates (EPCs) are already on the agenda for regulatory change. The government’s EPC Action Plan states that they must ‘move from a reflection of the features of a building to a true measure of ‘in-use’ building performance’. To the same end, the government has funded projects to develop Smart Meter Enabled Thermal Efficiency Ratings tools, for measuring the thermal performance of occupied homes. The new sensor technology developed by Knauf Energy Solutions is a good example of this. By placing sensors within a home, energy efficiency can be measured in the same way as energy generation, allowing the fabric energy performance of the building to be benchmarked for future designs.
Clearly insulation will play a key role in determining that energy performance. So how can we prepare today’s designs for the kind of in-use scrutiny that lies ahead?
The goal for architects is to ensure that the energy efficiency reflected in the specification translates into real performance in the real world. And that’s easier said than done.
A key factor to consider is the ‘buildability’ of the insulation material. Very few installations are 100 per cent perfect, just as very few wall cavities are perfectly uniform and flat. So, it makes sense to choose insulation that adapts well to imperfect site conditions.
Mineral wool insulation, for example, is engineered to meet these challenges. Its flexibility allows it to adapt to minor imperfections in a building’s substrate and maintain close contact in a way that rigid boards won’t. Spaces between rigid insulation boards also need to be taped with precision, leaving ample opportunity for human error, whereas the strands of mineral wool ‘knit’ together, minimising gaps and maximising performance. Simply put, mineral wool is easier to ‘get right’.
Of course, identifying the best product for the job is undermined if inferior product substitutions are made on site. To help protect the integrity of their specification, architects can work with manufacturers who provide support during the build phase of a project. This might mean training programmes, an approved network of installers, or tools that create a record of installations to confirm that the specified product has been installed, like Knauf Insulation’s app-based site reporting system, KinetiK.
Success through collaboration
Improving energy efficiency across the housebuilding sector is in everyone’s best interests. It has the potential to reduce operational CO2 emissions and make the cost of running a home more manageable. But to reach that goal, we all need to pull in the same direction. Architects must specify with ‘fabric first’ real performance in mind and developers must maintain the specification integrity on site.
In-use energy measurement isn’t here yet but it’s on its way. If we take this approach to housebuilding now, our homes will be better prepared when it arrives.