New non-domestic Part L will prove a “culture shock” — Net Zero

New non-domestic Part L will prove a “culture shock” — Net Zero

The new Part L of the building regulations for non-domestic buildings will provide something of a culture shock to the industry, according to Brian Byrne of energy consultancy Net Zero, unless it quickly gets to grip with the new standard.

This article was originally published in issue 26 of Passive House Plus magazine. Want immediate access to all back issues and exclusive extra content? Click here to subscribe for as little as €10, or click here to receive the next issue free of charge

Speaking to Passive House Plus, Byrne said that the imminent introduction of nearly zero energy building (nZEB) standards to Part L for both domestic and non-domestic buildings means the whole industry needs to look at compliance earlier in the design process.

“We find in some cases architects and engineers are sticking to backstop values, for example, and expecting that will be enough for Part L compliance. Then the local authority comes along and looks for DEAP or NEAP calculations,” Byrne said.

“We’ve even been called in a few times to provide Part L advice on projects that have already been built, and it gets fairly messy.”

But he added: “There are also great opportunities to save by looking at Part L early on. For example, perhaps using a particular heat pump might eradicate the need to install any solar panels.”

But while the new Part L for dwellings will demand a 25% improvement in energy performance compared to current rules, the new Part L for non-domestic buildings, the first update to this document in a decade, will mandate a 60% improvement.

“This will be a major shake-up for the industry. Before it was fairly straightforward to meet Part L for non-domestic buildings without a huge amount of thought, but that’s all set to change with nZEB,” Byrne said.

“For commercial buildings, there was not previously a requirement for an air test, or for renewable energy. You could typically pass using numerous default values. So the sector is in for a bit of a wake-up call, not just in terms of the measures that will be required, but also in terms of the documentary evidence required to prove a building complies.”

Based in Sandyford, Dublin, Net Zero was founded by Byrne, a mechanical engineer by training, who has extensive experience of producing commercial BERs and in domestic and non-domestic Part L consulting.

The company also employs Gavin Canavan, an architectural technologist who has qualifications in sustainable energy systems, advanced environmental and energy studies, and energy retrofit. He also has extensive experience working with architectural practices on projects of all types and sizes.

As well as Part L and nZEB consulting, the company also provides domestic and non-domestic BERs, energy design consultancy and heat pump grant assessments. See