How to read a Passive House window certificate

Separate the product from the building

The Passive House Institute, or PHI, certifies components and also operates building-certification standards. A component certificate supplies evidence about that component under stated conditions. Installing it does not, by itself, certify a house. PHI’s building criteria address the building as a whole, including its envelope, airtightness and building services. See PHI’s building-certification guidance.

Phius has its own window and door certification program. Its product data support calculations for the actual sizes and configurations in a project. A Phius product certificate and a PHI component certificate are different records: name the issuer and intended project standard whenever you request one. Phius also distinguishes its product climate recommendations from project approval; a recommendation does not guarantee suitability for an individual project. Read the Phius certification protocol, version 1.2, sections 1–2 and Appendix I.

If formal building certification is a goal, involve the project’s designer and certifier while specifications can still be coordinated. For a replacement project without that goal, the documents can still help you understand what a performance statement actually describes.

Read the identifying fields first

Work through the certificate before focusing on its headline number.

Save the complete document, including explanatory pages. If a brochure, database listing and PDF disagree, ask the supplier for clarification and the current issuer record before relying on the claim. Record when you checked it.

Keep the Innotech models distinct

Innotech’s product page links separate PHI certificates for Defender 88PH+ Pro and XI fixed and operable windows. The table records the documents checked on November 7, 2026. Those copies each stated validity through December 31, 2026; this historical record does not establish their status on a later date. Recheck the issuer records when specifying and ordering. Find the manufacturer’s certificate links.

These labels describe the listed components. Ask your project team which record applies to each opening. Keep the category, component ID and climate label together when sharing an extract; an efficiency class or climate description should stay attached to its specific record.

Distinguish Uw, Ug and installed performance

Uw describes whole-window thermal transmittance. Ug describes the glazing. The frame and glass-edge effects also contribute to the window result, so a glazing value cannot stand in for a whole-window value. An installed result additionally considers the window-to-wall junction. PHI’s transparent-component criteria distinguish these calculations. See PHI’s criteria, section 3.6.

Check the reference size and glazing used for a published result. For example, the XI fixed certificate explains its calculation basis on page 2 and lists validated installation situations on page 3. Those details give your designer something to compare with the proposed opening and wall assembly. Read the complete XI fixed certificate.

Phius certificates label center-of-glass data as U-COG and provide component data for actual-size modelling. Preserve the units, calculation method and climate conditions with any value; ask the modeller which inputs the project requires. See Phius’s window-certification guidance.

Carry the evidence into the order

Ask the supplier to identify the certificate and supporting drawing for every proposed configuration. Have the designer review the selected glass, opening sizes and installation junctions. Agree who will check that the delivered products and site details match the approved specification, and who will review substitutions.

Before approval, confirm:

• The issuer, exact model, operation and component ID match.
• The complete certificate and current status have been checked.
• Glazing and whole-window values remain clearly labelled.
• The project team has reviewed climate, geometry and installation assumptions.
• Any substitution returns to the responsible reviewer before ordering.

Bring your opening schedule and certification goal to Haven’s Passive House window discussion. Use the technical library to organize the supporting records, and the performance page to frame the questions you want the project team to resolve.