Four titles come up on every Passivhaus project, and they are routinely mixed up: consultant, designer, architect and certifier. The confusion is understandable. The roles overlap in skill, one person can hold more than one credential, and marketing copy tends to blur them. But on a real project they are distinct jobs with distinct responsibilities, and one of the distinctions is not optional. Getting them straight is the difference between assembling the right team and discovering a conflict of interest at certification.
The Passivhaus architect
The architect designs the building. On a Passivhaus project that means carrying the usual responsibilities, brief, form, planning, detailed design, coordination, while working to a standard that is far less forgiving of a loose junction or an awkward form factor than building regulations are.
A Passivhaus architect is not a different profession. It is an architect who designs with the physics in the room from day one, because in Passivhaus the geometry decisions made at concept stage, orientation, compactness, glazing ratio, largely set the energy outcome before a single detail is drawn. The buildings that reach the standard economically are almost always the ones where performance was a design input, not a fix applied later.
The Passivhaus designer
The Certified Passivhaus Designer holds a specific PHI credential earned through training and an exam. The title certifies that a person can do the technical work of designing to the standard: build and read the PHPP model, resolve thermal bridges, specify airtightness, size ventilation, and hold all of it to the target.
Here is the part people miss. A Passivhaus designer is not necessarily an architect. Architects, M&E engineers, energy assessors and contractors all sit the same exam and hold the same title. The credential is about competence in the standard, not about which profession you came from. On many projects the architect and the certified designer are the same person; on many others they are not, and the designer is an engineer or a specialist supporting the design team.
The Passivhaus consultant
A Passivhaus consultant is defined less by a credential than by how they are engaged. A consultant is brought in to advise and support a design team, usually because the practice does not have the specialist capacity in-house or wants an independent technical view.
In practice the consultant’s toolkit is the designer’s toolkit applied as a service: PHPP energy modelling, thermal bridge analysis, airtightness strategy, moisture risk, and support through certification. The work can run from a single early feasibility model that tells a client whether the standard is realistic on their site, right through to full technical delivery alongside the architect. The value of a consultant is specialist depth on demand, without a practice needing to carry that depth on every project.
The Passivhaus certifier
The certifier is the role that must be kept separate, and this is the distinction that is not optional. A Passivhaus certifier is an independently accredited party who reviews the completed design and evidence against the standard and issues, or withholds, certification.
The credential is separate from the designer’s. Certifiers hold their own PHI accreditation, and, critically, they must be independent of the design team on the project they certify. The designer builds the case; the certifier tests it. If the same party did both, certification would be marking its own homework, and the assurance the certificate carries would be worthless. We go deeper into what that review involves in what a Passivhaus certifier actually checks.
Can one firm do more than one of these
Yes, and a firm with real depth usually can. A practice can hold architecture, design and certification capability under one roof. What it cannot do is act as both designer and certifier on the same building. The independence rule is per project, not per company.
The way a serious multi-discipline practice handles this is with a firewall: when it certifies a project, its certifiers are independent of that project’s design team, and when it designs a project, someone else certifies. That is how the same organisation can offer both without ever compromising the certificate.
How to brief the right role
A short way to decide what you actually need:
- You are commissioning a building and want it designed to the standard from the start: engage a Passivhaus architect, or an architect working with a certified designer.
- You have a design team but no in-house Passivhaus specialist: bring in a consultant for the modelling and technical work.
- You want the credential yourself, or on your staff: that is the Certified Passivhaus Designer route.
- You need the building certified: appoint an independent certifier, and appoint them early, not at the end.
Where Mosart fits
Mosart holds all four capabilities: an architecture practice, certified designers and consultants, PHI-accredited certifiers, and the training school that qualifies designers in the first place. On any single project we keep the certification firewall in place, so the assurance stays real. If you are not sure which role your project needs, that is usually the first useful conversation to have, and often the answer is more than one.