Methodology
How VIG Guide evaluates sources, handles manufacturer claims versus independent data, and keeps sponsored content separate from editorial coverage.
How we evaluate sources
The editorial hierarchy, from highest to lowest confidence:
- International standards. ISO, EN, and ASTM standards define the test methods and acceptance criteria that qualify a VIG product. Where a standard applies, we cite it.
- Independent test reports. Where an independent laboratory has tested a specific VIG product, we cite the report rather than the manufacturer's own data.
- Manufacturer specifications and datasheets. Manufacturer-reported numbers are clearly labelled manufacturer-reported and attributed to the source.
- General industry ranges. Where a single source is not available, ranges across multiple products are summarised and labelled typical.
Manufacturer claims vs independent data
Where a manufacturer's claim can be checked against an independent source, we surface the comparison. Where it cannot — and for many emerging VIG products an independent source does not yet exist — we publish the manufacturer-reported figure with a clear label and treat it as a starting point for specifiers, not as a verified result.
Sponsored vs editorial boundaries
Sponsored listings — when they are introduced — will be marked and contained in a clearly labelled section of a page. Sponsored placement will never:
- influence the content of an editorial review or comparison
- be folded into a future editorial score or rating
- appear without a visible label
Brand profiles, comparisons, and pillar pages remain editorial regardless of any commercial relationship with the subject company. The full disclosure is documented atCommercial Disclosure.
Future rating system
VIG Guide will introduce an editorial rating system once enough verified data exists across the product set. The dimensions that will be evaluated, each in a single sentence:
- Thermal performance — measured centre-of-glass U-value versus the manufacturer's claimed value.
- Safety — availability of toughened or laminated variants and relevant safety-glazing certifications.
- Durability — accelerated weathering test results, edge-seal integrity, and design service life.
- Testing and certification — third-party certifications, ISO 19916 or EN 1279 compliance, and the breadth of independent testing.
- Optical quality — pillar visibility, haze, and birefringence under typical viewing conditions.
- Size flexibility — maximum available panel size and the lead time for oversize orders.
- Warranty — stated warranty term and what it actually covers.
- Availability — geographic distribution and lead time across the manufacturer's main markets.
- Value — cost per square metre at matched thermal performance, accounting for project-level savings.
Sponsored listings will never affect editorial scores. Manufacturer claims will always be distinguished from independently verified results.
Standards reference list
- ISO 19916-1:2018 — Glass in building: vacuum insulating glass, Part 1.
- EN 1279-5 — Insulating glass units: product standard, Part 5.
- ASTM E2190 — Standard Specification for Insulating Glass Unit Performance and Evaluation.
- ISO 10292 / EN 673 — U-value test methods for glazing.