Certification FAQ

The Passive House Institute provides a generic checklist of the evidence that builders are required to collect during the certification process, such as the photograph requirements. One of our members, Detail Green, also shares document examples with its clients to help them prepare for the final certification submission. So, it’s a good idea to consult with your certifier and/or designer in the early stages of the project if you need additional support.

There are a few common issues when it comes to inputting data into the PHPP. One is the ground sheet as it can be a little confusing if someone is new to Passivhaus. Another is the shading sheet because, if shading isn’t modelled in Design PH, it’s incredibly difficult to calculate everything correctly. In the past, it was also tricky to input data for heat pumps and cooling and heating systems, but with the recent update to PHPP 10, this is less of an issue. However, all of these issues are mitigated through the certification process as Passivhaus Certifiers are experienced enough to locate these problems before construction begins.

The best way to ensure you have the right documentation is to start a project folder with subfolders for each focus and store each piece of information as you receive it. For example, when you order the windows, put the window order form into the folder for windows. The same goes for your receipts and other information necessary for certification. If you’re unsure of what evidence to store, it’s best to consult with a Passivhaus Designer or Certifier before you start your project. Then, when you start the certification process, your Passivhaus Designer will set up a project on the certification platform so that you can begin uploading your evidence and list your project. Once the project is listed, you’ll see the nine different sections (each with its own subcategories) that tell you what you need to upload. For example, in the photograph section, there will be separate folders site photos, slab photos, etc.

Yes, you can as there’s no limitation on when you can start a certification. So, if you've designed a house to Passivhaus standards and the client has decided to certify during construction or build-up, you can start the process. However, there’s a higher risk that you won’t achieve certification because there could be something that was missed in the design stage or substitutions made that weren’t approved prior to construction starting. It’s also easy to misplace important data, such as window specifications, if certification isn’t a priority from the beginning.

One of the best ways to mitigate construction sequencing risk is through early involvement of the builder, such as in the detailed design stage. This gives designers a more practical perspective on the project and allows builders to start thinking about sequencing for the project and solutions for challenging aspects of the build.

Assuming it's a single-family house, you’d need to create drawings for all structural implications as well as unique and typical junctions — eg. wall-to-floor and wall-to-roof junctions, window installations and where the window is sitting in the wall, window schedules as well as wall sections. A typical wall section diagram will show the individual layers, ie. where the airtight layers go, where the breathable membranes go, and the insulation information.

The overall process for certifying a commercial or residential project is exactly the same. However, residential certifications are simpler to complete because it’s quite well-known how single-family homes operate, ie. their boundary conditions and what occupants will typically do in the home, so most PHPP assumptions can remain the same. When it comes to commercial buildings, there will need to be more in-depth reviews of the PHPP’s assumptions. This is because these buildings typically have more mechanical systems, thermal bridges, and other factors that affect achieving Passivhaus certification. So, certifying a commercial building will take more effort and time than typical residential projects.

The first thing you want to do is give your Passivhaus Designer the information regarding the design change so that they can revise the PHPP inputs and see if it still meets Passivhaus standards. Then, you’ll need to contact your certifier to verify the changes and make sure there are no mistakes.

Typically, Passivhaus Certifiers will conduct two pre-construction reviews (depending on the contractors’ experience) and one end-of-construction review for simple builds. The final review is always done at completion as that's when all the evidence of construction is put in. However, in commercial buildings and complex projects, certifiers may need to conduct multiple on-site checks during construction to ensure everything is running smoothly.

Certification credit goes to whoever has their name on the PHPP which tends to be the designer. So, it’s possible for designers to outsource things like WUFI analysis and thermal bridge modelling while still receiving credit if they own the PHPP.

Since all Passivhaus Certifiers must also have completed the Passivhaus Design course, you can think of certification as a peer review/quality assurance process where designers review other designers’ work. First, they compare the Design PH model to the PHPP to ensure that everything has been accurately exported. Then they use checklists which they tick off as they go through every tab of the PHPP and project drawings to ensure that design details have been entered correctly — such as whether the right thermal bridges have been assessed, all window data sheets have been included, etc.

Thermal bridging calculations are required for every project, but the number of calculations you have to do will depend on the complexity of the build. For example, if the building is well documented and sensible design practices are used, you may only need two or three thermal bridge models. However, if the building incorporates varied window placements and things like steel members and cantilevers then you’ll need to perform calculations for each unique thermal bridge. So, if you have a particularly complex build, your certifier will likely tell you which thermal bridges you’ll need to calculate and which ones you can ignore during the initial review.