Many people who seek a Passive House building do so for reasons of comfort, health and efficiency. Given these genuine and admirable outcomes, what role, then, does Passive House Certification play in a project?

Despite some misconceptions, it is not mandatory to Certify a project in order for it to be called a Passive House. This allows many more projects than would otherwise complete certification to attain the enduring and optimised outcomes. Passive House Certification is intended to verify and validate the as-built condition of a project. Key benefits include certainty that the designed measures have been achieved, as well as a marketable badge that can add value and surety for prospective purchasers.

In Australia, there are currently just seven Certified projects, all of them residential dwellings. Local certifiers are working on dozens more, though many more again will skip the Certification altogether. We chatted to the two accredited Australian Passive House Building Certifiers to find out more about the process, the key benefits, and what it is about Passive House that offers so much more to local practitioners than other building tools.

Building Certifiers: Luc Plowman (Detail Green) and Clare Parry (Grün Consulting)

What do you see as the key benefits for Certification?

Clare: It’s a stamp of quality, and a guarantee that the building has been constructed as per the design. Although many of our building standards and the tools they use have great intent, disappointingly, it is common for measures to be overlooked at construction stage to varying degrees. Certification is an independent verification; the Certifier remains independent of the project team.

Certification can result in added value to the project – there is data around for Australian projects showing that higher NatHERS ratings results in extra revenue at sale time. As Passive House exceeds NatHERS in terms of performance outcomes, we expect this to result in more value. Communication is key.

With so many methodologies around that all promise to achieve a high-performance building, and with a demonstrated performance gap of close to zero, Designers can also utilise Passive House Certification as a means to demonstrate a guarantee to their clients. We will likely see Passive House used as an alternative or agreed methodology to achieve other ratings such as NatHERS, NABERS and Green Star, as has been done both locally and overseas.

Why use a local Certifier?

Luc: Passive House Design, though straightforward in concept, painstakingly detailed in reality. As a result of local nuances, such as building practices, materials and regulations, a local certifier can make the process more streamlined. A tale relayed from a NZ project using an international Certifier was that they made some incorrect assumptions in their modelling that indicated their project had failed, sending the design team into a spin! Something that might be avoided using someone au fait with the region. The key differences, as I see it, in using a local certifier are:

  • In depth knowledge of local construction types and techniques
  • Better understanding of the local climatic conditions and how that translates into PH construction
  • Ability to provide site inspections to verify construction / assist with on site issues as necessary
  • Quicker turn around on the certification process and queries during design

What is the difference between a Passive House Designer and a Passive House Certifier?

Luc: A Passive House Designer sits on the design team, hopefully as an integral member, and advised the team throughout to design and construction. They may have dual roles, e.g. as the architect or designer, or the engineer. The Passive House Certifier remains independent, it is this independence that gives objective value to the Certification. You can be sure that the Passive House Certification is a true reflection of the project’s quality of build and that the building will perform as modelled.

Do you think the number of Passive House projects will increase?

Clare: Absolutely. There are at least 20-30 projects currently in various stages, and targeting Certification. Movement at various levels suggests that Passive House measures will be integrated in many sectors of the building industry, from incorporation at local through to national guidelines and codes. As the market matures, and products and services become more extensive and competitive, the cost of achieving Passive House will make as much sense as achieving any good quality build.

Do you think the cost of Certification is a barrier to its implementation?

Luc: It can be. It seems that the hardest part is selling the certification process and fees, I’m coming across a lot of people who like the idea but don’t want to spend the extra $ on certification.  So the easier it is to find us / know there is are local certifiers the better.

 

Clare: In my experience, it was quite difficult to get real value from the Certification process when the Certifier was thousands of kilometres away and operating in a different time zone. The real benefits are when you have the Certifier involved in the project from start to finish. Especially when your team might be new to Passive House, it can be extremely useful to sit down with the Certifier (or at least Skype!) and resolve things in real time, with the whole team. If they can be involved in a conversation with the Passive House Designer throughout the project, the outcomes can be quite well resolved and that’s the strength of the approach.