Standards - Hetreed Ross Architects

What Standards Should I Build To?

Starting from scratch, it is important to make the right decisions about the design and performance standards you choose, to ensure a building that is as sustainable as possible whilst still being affordable.

Building Regulations set the required minimum mandatory standards for energy conservation. Other organisations have optional schemes which define more onerous standards for achieving sustainable buildings. See below for more information on BREEAM, Passivhaus, EnerPHit, AECB, Code for Sustainable Homes and Building Biology.

The options available:

Building Regulations: Part L Conservation of Fuel & Power

The Building Regulations set out the minimum standards for design and construction with regard to conservation of fuel and power. They are mandatory so this is the base level you should achieve for any new building. The Building Regulations can be downloaded from their website.

PHI Passivhaus

A building methodology created by the Passivhaus Institut (PHI) in Germany, increasing in popularity, which results in an extremely low energy building with high levels of user comfort. It is backed up by certification which seeks to ensure that the building is both designed and constructed properly so that its actual performance is as intended. The level of rigour is unique amongst the standards. It does not rely on bolt on technologies; however different Passivhaus Classes can be achieved with more renewable energy provision. Learn more about Passivhaus in the UK on this website.

The principles of passivhaus are:

Very high levels of insulation
Extremely high performance windows with insulated frames and shading to prevent excessive solar gain
Airtight building fabric – no draughts
‘Thermal bridge free’ construction – no cold spots
A ventilation system with heat recovery

If you can’t quite manage full passivhaus:

PHI Low Energy Building

The Passivhaus Intitut Low Energy Building Standard is suitable for new builds which for various reasons do not fully comply with the more ambitious passivhaus criteria.

PHI EnerPHit

The Passivhaus Institut also defines a slightly relaxed standard specifically for retrofits called EnerPHit. The EnerPHit standard recognises the constraints imposed by working with an existing building and has been created with lowered airtightness and heating demand criteria specifically for these reasons.

A last word on PHI certification…

A building designed and built “to Passivhaus Standards” can theoretically achieve the same results as Certified Passivhaus, but without the rigorous checking carried out by a certifier it is less likely to do so. Quality of the design, verification by PHPP (software that assesses a design’s energy performance) and careful construction including airtightness tests are all critical to ensure the end result performs as well as the design, without certification bear in mind that the independent scrutiny and checking does not take place.

Passivhaus certification is onerous but it is also what ensures the results are as good as the design intent. The PHI have produced a detailed guide to obtaining certification.

Also worth reading: “Why bother with certification?” from one of our favourite Passivhaus bloggers.

The AECB Building Standard

A less onerous version of Passivhaus Low Energy Building, but it uses the same Passivhaus Institut assessment tool PHPP for design assessment. The building can be certified by the building’s energy consultant. Learn more from the AECB website.

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BREEAM Standards

(Building Research Establishment Environmental Assessment Method)

“BREEAM is an international scheme that provides independent third party certification of the assessment of the sustainability performance of individual buildings, communities and infrastructure projects. Assessment and certification can take place at a number of stages in the built environment life cycle, from design and construction through to operation and refurbishment.” There are specific standards for different building types including homes, for both new build and extension and refurbishment projects.

“The assessment criteria and process focuses on the design of the building from concept stage right through to a fully constructed building. It requires evidence to support the design and construction decisions, agreed during the development of the project, and ensures they have been fully implemented.”

BREEAM measures sustainability in a series of categories, ranging from energy to ecology. Each of these categories addresses the most influential factors, including low impact design and carbon emissions reduction; design durability and resilience; adaption to climate change; and ecological value and biodiversity protection.

Learn more about BREEAM standards and specifically for the home.

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Also worth a mention:

Code For Sustainable Homes

(withdrawn)

This Code has been withdrawn by the government and is no longer mandatory except in some specific circumstances such as a planning condition; however a building can still be designed to meet the code. There are various levels and the code relies on achieving sufficient credits for various sustainable features and standards. Learn more from the Code for Sustainable homes website.

Building Biology Standard

This standard assesses the physical, chemical and biological risks encountered in different parts of a building. It offers guidelines on how to perform specific measurements and assess possible health risks. Learn more from the Building Biology website.

This standard is particularly appropriate to those who are concerned about health aspects of their project and can be considered alongside other sustainability standards.

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Which One Is Best?

All the standards seek to improve the sustainability of a building which is a good thing. At Hetreed Ross we believe following the Passivhaus route makes perfect sense. Providing a very highly insulated, long life building that needs very little energy to run is a better way to spend money than to invest in lots of shorter life green technology. Of course if you can afford to do that as well it can further increase the sustainability. AECB’s The AECB Building Standard is also a good way forward, it uses the same software (PHPP) for verification and follows the same principles as Passivhaus but with lower requirements, it has a similar rigorous approach. Where Passivhaus is very precise about the performance of the building envelope; BREEAM is more holistic with a comprehensive assessment which includes the building’s surroundings, comfort, energy use, customer experience and more; this may be an appropriate standard for commercial projects and residential developers.

We are happy to work to any of the standards mentioned above. Most often we design buildings following the principles of Passivhaus without following the full certification route, as a building often lacks the basic elements required to meet the criteria because of the constraints of a site or planning etc. We always aim to make a building more energy efficient than is demanded by Building Regulations.

Hetreed Ross Architects are RIBA Chartered Architects and Environmental Designers, for Bath, Bristol, Somerset, Wiltshire, Gloucestershire, Dorset and the South West. AECB, EASA and Green Register members. Registered office: Hetreed Ross Architects, Attika Workspace, Bath Brewery, Toll Bridge Road, Bath, BA1 7DE.