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Future Homes Standard updates – The new targets

22 Jan 2021

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Future Homes Standard updates – The new targets

The new version of Approved Document Part L is set to go live in England in June 2022 and, as anticipated, the Target Emission Rate will be cut by 31%.

This means new dwellings will need to be designed with a smaller carbon footprint in mind, but that’s not the only thing that’s changing.

Finding a path to compliance with the new rules doesn’t just mean taking an old SAP calculation and making it 31% better. The new Part L includes additional, mandatory targets that work together to push designers into creating all-round greener homes for future developments.

Let’s start with the Target Emission Rate

The construction industry is familiar with the TER. Every new home since 2005 has been assessed against it to prove low levels of CO2. But in the coming years, as we move closer to a zero carbon world, the importance of the Target Emission Rate is going to become less relevant. We need to introduce new targets now in readiness for the day that every new home has a TER of zero.

The upcoming change to Part L brings a 31% reduction to the TER with a further reduction (75% compared to today’s TER) due in 2025.

Make way for the Target Primary Energy Rate

The TPER is a new entry into SAP, and over time will take the place of the TER. Primary Energy considers two things – the amount of energy (in kilowatt hours) a house is expected to require for heating, hot water, lighting, ventilation and showers, but also how much additional energy is needed to produce that energy in the first place. It considers the power which is wasted in our power stations and gas refineries.

The maths behind the TPER is near identical to the TER, but will be measured in kWh instead of CO2.

And Welcome Back to the Target Fabric Energy Efficiency

We were expecting the TFEE – which was introduced in 2014 – to be replaced with an affordability target, but the Government’s had a change of heart.

TFEE ignores any clever systems that are put into the dwelling and just looks at the fabric shell.

To pass TFEE, developers need to put emphasis on low U-Values, low thermal bridging losses and low air leakage scores. The level of difficulty for the new TFEE hasn’t been decided yet, but the Government’s considering making it 15% more difficult than in the current SAP.

To pass AD L, you’ll need to comply with all three targets

That’s not an easy challenge considering we’re looking at three different factors.

The Target Primary Energy Rate isn’t going to like standard electric heating systems without renewable offsetting, but will be more relaxed about gas boilers and heat pumps.

But the Target Emission Rate will favour all kinds of electric heating, especially heat pumps. Gas boilers will struggle to meet this target without the help of PV panels.

And the Target Fabric Energy Efficiency doesn’t care if you’re using a heat pump, boiler or your own hydro-dam… if you’ve not invested in the fabric, it’s not going to work.

Designing a dwelling which is low energy, low carbon and has a low fabric heat loss isn’t impossible. The challenge is tying everything together with your specific on-site constraints, practicalities, budgets, available personnel skills and supply of building materials.

There isn’t a one-size-fits-all approach to the new AD L, but there is always a solution in there somewhere.

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Author

Jon Ponting

Energy And Sustainability Specialist

Email

Jon Ponting

Energy And Sustainability Specialist

jonp@energistuk.co.uk