Guide To Visible Transmittance

Best Visible Transmittance Ratings

The ideal VT rating is the highest visible transmittance number you can achieve, while synonymously achieving the best U-factor and SHGC numbers. So, how does this work? Typically, the best solution is a simple low-e glass, which allows a VT around 50 to 55, while still achieving good energy efficiency ratings. Generally, ere are some generic numbers consumers can expect with with various types of window glass. Clear glass will allow 78% to 84% visible-spectrum light through the window (high VT, not very efficient). Low-e II glass allows in 72% visible-spectrum light. Laminate glass allows in 79% visible-spectrum light. Lastly, a triple pane low-e 3 with a tint will allow in 48% to 54% visible-spectrum light (low VT, very efficient).

Associated Costs

Here are the associated costs with upgrading from clear glass to other glass options. As the cost goes up, the visible transmittance goes down. However, the energy efficiency of the windows improves.

Clear Glass - Included

Low-e Glass Upgrade - $75 per window

Glass Low-e II Upgrade - $100 per window

Low-e III Glass Upgrade - $125 per window