One of the most consequential decisions on any new build project gets made before a single drawing is produced. Which performance standard are you designing to, and why?
It sounds like a technical question. It isn't really. It's a question about ambition, about what kind of building you want to be responsible for, and about how honest you're willing to be with yourself about the gap between minimum compliance and genuine performance.
A contemporary low-energy home designed with sustainability at its core - clean lines, natural materials, and expansive glazing connect the indoors with the surrounding landscape.
Part L of the UK Building Regulations sets the minimum acceptable standard for energy efficiency in new construction. It exists to prevent the worst outcomes, not to produce good ones. A building designed to comply with Part L will be legal. It will not necessarily be comfortable, cheap to run, or resilient to the energy costs and climate conditions of the next fifty years.
We see this regularly. Projects that have been carefully designed aesthetically, with excellent materials and considered spatial planning, but where energy performance was treated as a compliance exercise rather than a design objective. The result is a building that looks right but costs more to run than it should, and will continue to do so for the life of the structure.
Exceeding the minimum isn't idealism. It's the more rational position.
Passivhaus is the framework we return to most consistently, and it's worth explaining why, because it's sometimes misunderstood as a niche or expensive approach.
The Passivhaus standard originated in Germany in the early 1990s and sets quantified targets for heat demand, airtightness, and thermal comfort. What makes it distinctive is that performance has to be modelled and verified, not just designed for and hoped for. The methodology closes the gap between what a building is intended to do and what it actually does in use, which is a gap the construction industry has historically been poor at addressing.
In practical terms, a Passivhaus building achieves very low heating demand through high levels of insulation, an airtight building envelope, high-performance triple glazing, and mechanical ventilation with heat recovery. The fabric does the work. The technology serves the fabric rather than compensating for its failures.
The result is a building that's genuinely comfortable: stable temperatures, good air quality, no cold draughts near windows, no condensation. These aren't marketing claims. They're the measurable outcomes of a rigorous methodology.
We hold Passivhaus Designer accreditation at RISE and apply the methodology across our work. Not every project pursues formal certification, but the thinking that underpins the standard shapes how we approach every commission.
Two related standards are worth knowing about for projects where full Passivhaus certification isn't achievable.
EnerPHit applies Passivhaus principles to retrofit projects, acknowledging that existing buildings present constraints that a new build doesn't. The targets are slightly adjusted to reflect the reality of working within an existing structure, but the methodology is the same: model the performance, verify the outcomes, and close the gap between design intent and built reality.
PHI Low Energy Building is a step below full Passivhaus certification but remains considerably more demanding than standard building regulations. It accommodates constraints, whether site-specific, planning-related, or budgetary, that make full certification impractical, while still producing a building that performs substantially better than the minimum.
Both are useful frameworks for projects where the aspiration is clear but the constraints are real.
Passivhaus isn't the only route to a well-performing building. Depending on the project type and priorities, other frameworks have genuine value.
The AECB Building Standard takes a similar fabric-first approach to Passivhaus but with slightly less demanding targets. It's a credible and practical alternative for projects where full Passivhaus is a stretch, and it shares the same underlying logic: get the fabric right before reaching for technology.
BREEAM is a broader sustainability assessment used predominantly in commercial and larger residential projects. It covers energy, materials, water, biodiversity, and occupant wellbeing within a single framework, and is often required by planning authorities or funders on larger schemes. It doesn't go as deep on energy performance as Passivhaus, but it addresses a wider range of environmental factors.
The Building Biology Standard takes a different angle altogether, focusing on the health implications of the built environment: chemical off-gassing from materials, electromagnetic fields, humidity, and air quality. It's particularly relevant for clients with specific health sensitivities or a strong interest in the intersection of architecture and occupant wellbeing.
None of these frameworks is universally the right answer. The appropriate standard depends on the project type, the site, the budget, and what the client actually cares about. Part of our job is helping clients understand those options clearly enough to make an informed choice.
We don't apply standards mechanically. What we do is use them as a framework for ambition: a way of establishing what a project should achieve before the design process begins, and holding that ambition accountable through the technical stages of a project.
For most residential projects we integrate Passivhaus principles without pursuing formal certification, because the methodology is sound and the certification process doesn't always align with the constraints of a real project. What matters is that the fabric performs, that the energy strategy is coherent, and that the building delivers genuine comfort and low running costs rather than a compliant EPC rating.
The best outcome is a building that the people who live or work in it actually experience as better, not just one that performs better on paper. Those should be the same thing. With the right approach from the outset, they usually are.
Choosing a performance standard isn't a technical footnote. It's one of the most important decisions on a project, and it needs to be made early enough to actually shape the design rather than being overlaid on top of it.
At RISE we have that conversation at feasibility stage, before the floor plan is fixed and before the structural strategy is set. That's when it costs nothing to get right and everything to get wrong.
If you're planning a new build or a substantial retrofit and want to understand what the right standard might be for your project, we'd be glad to talk it through.
→ Email us at architects@risedesignstudio.co.uk
→ Or call the studio on 020 3947 5886
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