Commercial planning guide

VLT, solar heat gain and reflectance: reading film data

Commercial film data sheets use several values that describe different optical and thermal effects.

VLTSHGC

Editorial review: August 11, 2026 · Laura N. Mercerfield

What drives the decision

Visible light transmission describes visible light, while solar metrics describe a broader part of incoming solar energy.

What changes the budget

A darker-looking product is not automatically the best solar-control option.

Operations and lifecycle

Compare values using the same glass reference and test basis.

Planning boundary

Use rated manufacturer data for the glazing/film combination where available.

Educational planning only. Actual construction, code compliance, regulated systems, hazardous materials and safety-critical work require qualified professionals and current local requirements.