As passivhaus uptake has increased in recent years there has been plenty of discussion about whether a project can be designed to ‘passivhaus principles’ (short answer: no) and whether a project is still a passivhaus building if it isn’t certified (short answer: no, again). Setting aside these particular questions, why bother with passivhaus certification?

Here are three good reasons; Quality Assurance, Accountability and Performance that lasts.

1. Passivhaus certification is vital quality assurance.

There could be errors in the design. No architect, engineer or passivhaus designer/consultant is perfect, nor would they claim to be, and it is possible that small errors could creep into the design, the details or the data in the Passive House Planning Package. In the certification process, an independent passivhaus certifier checks these aspects of the project. While they are also not perfect, they bring a fresh set of eyes to the project and they are highly skilled and experienced at scrutinising passivhaus project documentation, energy and comfort modelling. They will spot errors that those more closely involved in the project or less experienced may not.

There could be errors in the construction. The performance gap that is rife in the construction industry is due in part to buildings not being constructed in accordance with the design details. There are various reasons for this and blame does not lie wholly with any one party. (Architects, before you jump to blame the builders: just how buildable and practical are your details?) However, the passivhaus certification process involves checking what is built on site and this ensures that the construction accurately matches the design details.

There could be changes made during the construction. Passivhaus certification ensures that when this happens, the details are fully resolved so the performance isn’t compromised.

All this adds up to considerable peace of mind for the client.

2. Passivhaus certification holds designers and builders accountable.

The reality is, to ramp up building performance standards, designers and builders need more accountability for what they deliver. Having clearly defined targets, as the passivhaus standard does, and knowing that someone is going to check their work during the certification process sets this in place.

Quite possibly this initially scares a lot of designers, and with good reason. And equally likely, knowing someone is going to check the construction on site and hold them accountable initially scares as many builders. However, once they are over this reaction, there is a lot of comfort provided by clearly defined targets and an independent check, provided they do their job properly.

Notionally building control officers do check designs and construction. But really, how much can they, and do they, actually check? And how thoroughly? And of course building regulations are a minimum standard, the passivhaus standard exceeds the regulations by a considerable margin.

3. Passivhaus certification ensures lasting performance.

The passivhaus standard is the gold standard for low energy and occupant comfort across the globe. It is backed by over 30 years of data demonstrating that it delivers what it promises, something no other standard comes close to. And certified passivhaus buildings maintain performance over time. Buildings notionally designed to meet the passivhaus standard benchmarks, but not certified, do not.

In the UK, there is an expectation that in Germany and Austria they know how to do it right, so probably don’t need to bother with certification. But as Deiter Herz presented at the UK Passivhaus Conference 2013, this simply isn’t the case. Even in Austria, certification is the difference between performance that lasts or doesn’t. And this is with buildings designed to meet the passivhaus standard benchmarks and modelled in the passive house planning package, not just designed to some notional ‘passivhaus principles’.

Who wants the performance of their building to noticeably degrade over time? Who wants their energy bills to rise and comfort to decrease over time?

No one, of course.

Architecture must change.

We need buildings with reliable radically low-energy consumption and radically low CO2 emissions. We need buildings that provide healthy comfortable indoor environments. And we need these qualities to last.

Passivhaus can deliver all of these. And passivhaus certification provides the quality assurance and accountability needed to make these a reality.

Wondering about how to ensure your project is certified? The Passivhaus Trust has a list of UK organisations that have been approved to assess and issue the Quality Assured Passivhaus Certificate. The full list of international organisations is on the Passivhaus Institute website here.