There is no single price for Passive House certification. The fee depends on the size of the building, its complexity, the number of distinct unit types, and whether a complete PHPP model already exists. What you can pin down is what the fee covers, what drives it, and how the process runs alongside design and construction.
Anyone quoting a flat figure without asking about the project is guessing. The honest answer is a short conversation about scope, and this article explains what that conversation covers so you can get a meaningful number quickly.
What drives the cost of certification?
Certification is a review process, so the fee reflects how much there is to review. Four factors do most of the work:
- Size. A larger building means more envelope, more junctions, more services and more evidence to check at both design and as-built stage.
- Complexity. A simple form with a clear thermal envelope reviews quickly. Stepped sections, mixed construction types, complicated services strategies and unusual junction details all add review effort.
- Number of distinct unit types. This is the factor that surprises people, and it works in the client’s favour at scale. Certifying a scheme of hundreds of homes built from a handful of repeated unit types is far more efficient per unit than certifying the same floor area as one-off designs. It is part of why Passivhaus has proven viable on schemes like Shanganagh Castle in Dún Laoghaire, with its 550+ Passivhaus homes, and Seven Mills in Dublin, the 5,500-home new town where Mosart acts as certifier.
- The state of the PHPP. If a competent, complete PHPP model exists, the certifier reviews it. If it does not, someone has to build it first, and that is a separate piece of work with its own fee. A tidy model with clear documentation is the cheapest project to certify.
A fifth factor sits behind these: how early the certifier is engaged. Problems found at design-stage review are corrected on paper. The same problems found at as-built review are corrected on site, or not at all.
What does the certification fee include?
A certification appointment typically covers three things. First, the design-stage review: a systematic check of the PHPP model, drawings and details against the certification criteria, with feedback to the design team. Second, the as-built review: verification that the evidence from site, including the blower-door test result to EN ISO 9972, photographic records and commissioning data, matches the model, and that the final PHPP reflects the building as constructed. Third, registration with the Passive House Institute and the issue of the certificate itself.
What it does not include matters just as much. Certification is independent review, not design assistance. The certifier checks the work; they do not do the design team’s modelling, detailing or thermal bridge calculations. Keeping those roles separate is what gives the certificate its value, and reputable certifiers are careful about the boundary.
How long does certification take?
Less time than most teams expect, because the reviews run in parallel with design and construction rather than adding stages to the programme.
| Stage | Typical duration |
|---|---|
| Design-stage review | 2–4 weeks once the PHPP is submitted |
| As-built review | 4–8 weeks |
| PHI processing | Typically 4–8 weeks |
The design-stage review happens while the project is still on the drawing board, and the as-built review runs as construction evidence is assembled towards completion. On a well-run project, certification adds no time to the critical path. What stretches the timeline is incomplete submissions: a PHPP with gaps, missing site evidence or an untested envelope sends the review back around the loop.
Is certification worth the money?
For most projects, yes, and for three concrete reasons.
First, independent verification. The certificate is the only widely recognised confirmation that a building performs as its model claims, backed by measured airtightness and third-party review. For a client, a funder or a future purchaser, that is the difference between a claim and a fact.
Second, access. Certification is increasingly written into funding conditions, procurement requirements and client briefs. On those projects the certificate is not optional, and the cost question becomes one of timing and efficiency rather than whether.
Third, and least appreciated, the design-stage review catches errors while they are cheap. A misread junction, an optimistic ventilation assumption or a treated floor area discrepancy found at design stage costs a revision to the workbook. Found after handover, it can cost the certificate. Across the 500+ units Mosart has certified, the design-stage review has consistently been where projects save more than the certification fee costs.
How do I get a number for my project?
Gather four facts: the building type and approximate floor area, the number of distinct unit types if it is a multi-unit scheme, whether a PHPP model exists, and the programme dates. With those, a certifier can give you a firm fee rather than a shrug.
If junction calculations are still outstanding, our free thermal bridge estimator will help you scope that piece of the work in a few minutes, and a certifier confirms the figure within a working day.
Where Mosart fits
Certification is core work for Mosart, with seven PHI-accredited certifiers in-house. Our Passivhaus certification service covers design-stage review, as-built review and PHI registration. For a fee against your brief, talk to a certifier.