Future Building Standard – Tougher SBEM targets

Future Building Standard – Tougher SBEM targets

The Government is changing the way we design and build non-residential units in England from next year.

The Future Buildings Standard is a consultation which follows-on from the more widely publicised Future Homes Standard. That’s the policy which is encouraging developers to move away from gas boilers in new builds from 2025.

FBS is following a similar route, and encourages the use of low-energy heating systems (heat pumps and air conditioning) onsite energy generation.

This is the first time in a decade that Approved Document L2 has seen any significant shift in the drive towards more energy efficient buildings, yet another uplift to the targets has already been confirmed to follow just three years later.

To deal with the hear-and-now, the current consultation proposes this ‘interim’ Part L will go live in June 2022. This release will move the goalposts someway towards the ultimate 2025 target.

Next year we will see the Target Emission Rate of SBEM reduced by around a quarter… the Government’s preferred approach is a 27% uplift.

That doesn’t mean the energy performance of your building will need to improve by 27%. It’s never that easy in the World of SBEM.

There are two big adjustments being made in the background of the calculation which will distort any fair comparison being the current and proposed SBEMs. One is to do with the decarbonisation of electricity which means the Target Emission Rates will suddenly favour electricity over gas and consider a far lower impact on lighting and ventilation systems.

The second change is to do with the occupancy assumptions of different building types. These tables of data control the amount of energy use assumed for heating, hot water, ventilation and lighting depending on the specific room usages of your building. For example, an office is assumed to use a lot of lighting; a sports hall is expected to use a lot of hot water.

As the way we work and use non-residential buildings changes over time, so must the occupancy data used by SBEM so it better reflects the real world.

These adjustments are so great, that some buildings may not need any improvements to meet compliance… under the new SBEM they may already be 27% more efficient. On the flip side, some will need to go further to reach the new target. It all depends on the building type, the fabric design and the heating details. The 27% of a nationwide average.

But the TER is not the only target we have to contend with under the proposed new regs. A second new target – the Primary Energy Rate – is being introduced. Instead of focusing on the carbon footprint of the building, TPER measures the energy use. Primary Energy will become the dominant target in future years as the usefulness of the TER will diminish the closer we get to zero carbon.

Maximum U-Values are also changing. Heat loss floors, external walls, roofs and windows will all need to meet tougher targets than buildings constructed today. This is the first significant change to the limiting U-Values since SBEMs were made mandatory in 2005.

What does all this mean?

Approved Document L2 and the SBEM calculation is due an overhaul, and in the next five years we’re going to go through two seismic shifts in how the targets are calculated. By the time we get to 2025 the majority of SBEM calculations will need low carbon heating and far-improved building fabric than we build today.

For the interim update, we need to reach a middle ground where PV panels will be more common, thicker insulation will be a must, heat pumps will start to replace gas boilers, and better ventilation systems will be more critical to compliance.

Energist can run sample SBEM models against the proposed consultation targets to see how non-residential units on your next development may fare before the regulations go live. Contact us to find out more.