Passivhaus and PHPP assessments

The Passivhaus standard is a way of delivering buildings (both domestic and non-domestic) that go beyond national building regulations in terms of energy efficiency and comfort. To demonstrate that a building meets the standard, the specification is modelled in software called the Passivhaus Planning Package (PHPP). Without a PHPP assessment, a building cannot be Passivhaus-certified.

What is the Passivhaus standard?

The Passivhaus standard comprises a series of quality assurance requirements, all of which must be met in order for a building to be certified at completion. The requirements help to ensure a comfortable building is achieved for the end occupants/users.

For example, they specify an airtight building fabric with a minimum rate of controlled ventilation, to eliminate draughts and provide good air quality. They require that the internal surface temperature of windows must not drop below 17 degrees C on the coldest day of the year, while also ensuring that the building does not overheat in summer.

The quality assurance requirements also make sure that the building is energy efficient, by specifying targets for heating demand and primary energy demand.

Can PHPP assessments only be carried out for Passivhaus projects?

The PHPP software is a design tool, intended to predict the energy and comfort performance of a building as accurately and reliably as possible.

Theoretically, any building’s specification could be inputted into the software to assess its performance. Such an assessment would only be against the Passivhaus standard, as PHPP is completely different from the software designed to assess regulatory compliance.

If you are going to the trouble of assessing a building specification in PHPP then it’s likely that you’re aiming for Passivhaus certification on your project. If you don’t want full certification but still want to adhere to ‘Passivhaus principles’, a PHPP assessment would be required. Designing to ‘passive principles’ and designing to ‘Passivhaus principles’ are two different things.

What does a Passivhaus Designer do?

A Passivhaus Designer is somebody who has undertaken training and achieved certification to demonstrate their knowledge and understanding of the Passivhaus standard. They understand the quality assurance requirements, and can communicate them to others engaged on the project, helping to steer the project from conception to being ready for certification.

Top tips

  1. Understand what the Passivhaus standard is, and what it will mean for your project, before committing to it.
  2. Research whether any local contractors have Passivhaus experience – you’re going to rely on them to build to the correct level of quality.
  3. Speak to us for advice on whether Passivhaus is right for your project as soon as possible, and then keep us involved. That’s the best way to help us steer you towards certification.
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