From ‘walk-on extra’ to star of a decarbonised energy system in three easy steps.

Categories: Blog

Written by Steven Heath from Knauf Insulation, a member of the SEA.

The UK Energy Performance Certificate (EPC) could, and must, be the platform on which to build a decarbonised energy system. We made this claim to sceptical experts from the policy, energy, finance and consumer protection worlds in London’s Reform Club.

To deliver on that potential, we argued three low-cost, no-regret steps are needed. And with SAP (Standard Assessment Procedure) reform and the debate on EPCs live, the window of opportunity is now. Although technical in nature, these three steps will assure people that they got what they paid for. Building trust in those EPC energy bill estimates to inform household decision making is vital. What current answers do we have to the questions: ‘will my new home really be that cheap to run?’; ‘will a heat pump be cheaper to run than my boiler?’; ‘if I retrofit my home, will I really see those savings?’.

Such questions go to the heart of the wider sustainability debate as we face up to the costs and compromises action on climate change requires. Lincoln put it best “…public sentiment is everything. With public sentiment, nothing can fail; without it nothing can succeed.” The three steps below allow risk to be allocated correctly (i.e. not left with occupants) and might just mean we retain public sentiment:

  1. Validate, accredit and audit in-use fabric energy efficiency measurement tools for the EPC & wider policy (new build and retrofit).
  2. Require a heat meter to be installed alongside any new heating system—heat pumps or boilers.
  3. Publish a five-year transition plan to require all policy—retrofit and new build—to shift to in-use, performance-based measurement and away from guesstimates.

Failure to take these steps means the EPC will not tell buyers of new homes, or retrofits, whether they received the promised highly efficient home fabric, or the high heat pump efficiency. Instead, it would only ‘indicate’ whether this was achieved as nothing is measured. EPCs can currently make no promises, nor can they support any performance guarantees as a result.

Taking the three steps allows the EPC to transition from ‘estimation’ to ‘measurement’. This allows occupants, house builders, retrofitters, governments, and the electricity grid to know if the expected performance was delivered. A reformed EPC could even make the leap from offering measured outcomes to supporting guaranteed ones. In insurance terminology, an approach where risk is correctly assessed, allocated and managed.

It is easier to imagine the impact of these steps through a collective, aggregated lens. Picture a UK-averaged national heat pump seasonal efficiency after the targeted 600,000 installs per year has electrified the bulk of our heating. Now, is that national average efficiency above 3.5 kWh of heat delivered for every 1 kWh of electricity in, or is it below 2.5? The former offers a cost equivalence or better to current gas heating; the latter does not.

Consider also, the total kWh of heat needed to heat this ‘aggregated national home’ to warm, comfortable temperatures. Does it require minimal heat even in cold temperatures or did the new homes we built, and those we retrofitted, fall short of expectations? This is a national performance gap, where the metric could be counted in ‘additional power stations we didn’t need to build’.

Every retrofit, heat pump, and new home fabric that underperforms would not only undermine that national average, but also erode public sentiment towards action. Not all homes have to underperform—ten percent of UK homes is still a lot of homes. A cost-effective energy transition means we must make every effort to ensure heat electrification delivers high efficiencies and our retrofitted, and new, homes can be heated for the low energy demand claimed.

Of course, we don’t live in a collective, aggregated home. So, we need a tool to show in each home—new or retrofitted—that a ‘good outcome’ has been achieved. This tool must ultimately work for every householder, while also aggregating into a clear view on national success. The Energy Performance Certificate has to be that tool. Or at least a reformed version of it.

The underpinning calculations for EPCs (using SAP software) are up for consultation, as are the Future Homes and Buildings Standards. EPCs themselves are also due to be consulted on in the new year. As many government policies and regulations covering retrofit and new buildings use SAP and EPCs to measure delivery and outcomes, few consultations are so important. Any reader inclined to share their views with the Government, or with those drafting manifestos, please do consider the three easy wins listed. Question 40 in the Future Homes Standard consultation proposes our step 1 already—although only asking for real performance measurement on a voluntary basis.

Yes, the steps are technocratic, but this detail might just mean Lincoln’s ‘public sentiment’ remains with us rather than against.

Lastly, you can find out how to include these measurement tools in the EPC software in this technical briefing note from Knauf Energy Solutions. Feel free to include the note in any consultation responses.

The technical innovation is here, it just needs policy reform to flourish with it.