WJ Architectural Glass · Buyer education
A coating and an assembly
Low-E refers to a low-emissivity coating used to manage radiative heat transfer. An insulating glass unit describes panes assembled around a sealed cavity. The two concepts work together, but neither name is a complete product specification.
Write the build-up in order
List the panes from outside to inside, including thicknesses, treatment, coating position, cavity and any laminated construction. Also state overall thickness and the framing constraints. This makes it easier to compare supplier proposals without overlooking a changed component.
Compare the same performance basis
Ask whether a quoted thermal value describes the glass centre or the whole window. Solar gain and visible transmission should also correspond to the proposed make-up. A headline number from another configuration is not evidence for the unit being ordered.
Resolve interfaces before production
The glazing contractor should confirm edge cover, sealant compatibility and installation details. Record the accepted drawing revision and documentation requirements. A complete specification reduces the chance of receiving a technically different unit with a superficially similar appearance.
General guidance, not a project design or a declaration of certified performance. Confirm the exact glass construction and documentation with the project team.
Further Technical Reading
External references explain material principles; their product specifications are not WJ production specifications.
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