How to verify a window test report
A report can be genuine and still be the wrong one. The number is real, the laboratory is real — and it still does not cover what you are buying.
Four checks, in this order, close that gap. They work for NFRC, CE / EN 14351-1, AS 2047 and CSA / NAFS alike.
Why the usual check is not enough
The usual check
Ask for a certificate. Receive a PDF. See a logo, a number and a table of values. Accept it.
What actually has to be true
The number is traceable to the body that issued it; the tested series is the series you are buying; the tested sizes include your openings; and the values meet your specification.
The four checks, in this order
Run them in sequence. A report that fails check 1 never reaches check 4 — and a report that passes 1 and 2 can still fail 3.
Authenticity
Is the report real, and is it traceable?
A report number should be traceable to the issuing body or its directory — not only to a PDF the supplier sent you. Photocopies, screenshots and re-typed tables are not evidence. An accredited body issues the report; a factory does not issue its own.
Identity
Is it the series you are actually buying?
The profile series, wall thickness, glass build-up, hardware and thermal break on the report have to match the units on your order. A look-alike series, or the same profile with a different wall thickness, invalidates the number even though the certificate is genuine.
Coverage
Do the tested sizes and configurations include your units?
A report covers the sizes that were tested. If your openings fall outside the tested range — oversized units, gable and shaped windows, or a different opening direction — the tested value does not carry over. This is the gap that shows up most often.
Conformance
Do the numbers meet every requirement on your drawings?
Match the reported values against your specification line by line: thermal, air leakage, water tightness, wind load, and the safety glazing requirement of the destination market. Passing a test is not the same as meeting your project.
Five things to ask for — before you accept a claim
- 1The report number, and the name of the body that issued it. Not the factory’s own summary of it.
- 2The exact series and wall thickness listed on the report, so you can compare it against the quotation line by line.
- 3The tested size range, stated in writing — including whether shaped and oversized units are inside it or outside it.
- 4The values that matter to your project only: thermal, air leakage, water tightness, wind load. Skip the rest of the table.
- 5A traceable source you can check without the supplier’s help — the issuing body’s directory, or a contact at the laboratory.
Common questions
A US report (NFRC / U-factor) — can I use it for a Canadian or European project?
The supplier says the report covers "the whole series". Is that enough?
Can a factory issue its own test report?
What if the values pass but the report is for a different glass build-up?
How do I check the report without a technical background?
Where does this fit with certification?
Want a second pair of eyes on a report?
Send the report and the specification it is meant to satisfy. We will tell you in writing which of the four checks it passes, which it fails, and what to ask the supplier for next. We work for the buyer and take no commission from any factory.