To read part 1 of this article, please click here.
The Passivhaus standard is a specific energy performance standard. It sets out the energy performance targets that must be met in order for certification to be achieved, which includes targets relating to Specific Heating Demand, Specific Cooling Demand, Specific Heating Load, Specific Primary Energy Demand and Air Changes per hour. It is a much higher standard than traditional Building Regulations.
The energy balance must be assessed using the Passive House Planning Package (known as PHPP). This is a certification process used to inform the design process and to assess compliance with the Passivhaus Standard.
Passivhaus standard checks take place at Design stage, and then the building will be certified again after build completion as a ‘Quality Approved Passivhaus’.
The term Passivhaus cannot just be used to describe a building where environmental features have been incorporated into the design. A Passivhaus building has to be certified.
However, it is possible to claim a building is a ‘non-certified Passivhaus’, but you would need to ensure that the building would meet all the requirements of the Passivhaus standard.
It is recognised by the Passivhaus Institut that refurbishing an existing building to a Passivhaus design will be more difficult than creating a Passivhaus new-build. As such, there are slightly relaxed criteria for these buildings to meet the Passivhaus standard.
There is also a relaxed standard for refurbishment or retrofit products, where the existing construction means meeting the full standard isn’t possible. This is called the EnerPHit standard.
It is important to remember that Passivhaus is a strict term, and there are an increasing number of buildings claiming to be Passivhaus or have ‘Passivhaus principles’ when they are uncertified and falling short of the standards required. Making false claims that a building is a Passivhaus would be viewed as misleading and fraudulent under the Consumer Protection from Unfair Trading Regulations 2008 (CPRs) and the developer would be subject to legal claims, sanctions and damages for breaching the CPRs.
DEFRA have published ‘Green Claims Guidance’ which promotes clear and substantiated environmental claims on products and in marketing, and have the power to prosecute claims against false claimants. The Passivhaus Trust have also enforced against incorrect use of the ‘Passivhaus’ term.
There is a view that there is a premium to be paid for Passivhaus construction; some developers would put this at an increase of 20% on the build cost. Although there are significant environmental benefits, it is important to be aware of extra cost implications.
Passivhaus is a quality assurance standard as well as an energy standard, and you would need to ensure that you have a team in place that can support you in all aspects to enable your construction to meet that standard. If you are interested in designing and developing a Passivhaus building, our construction and development teams would be delighted to work with you.