Window Radiation Transfer


Clear glass High-transmission low-e Spectrally selective low-e

1 Most solar heat enters window

2 Most long-wave radiation is transmitted out window

3 Most solar heat enters window

4 Most long-wave radiation is reflected back by low-e coating, reducing winter heat loss

5 Most solar heat is reflected by spectrally selective coating, reducing summer heat gain

6 Most long-wave radiation is reflected back by low-e coating, reducing winter heat loss

Excerpted from No-Regrets Remodeling by Home Energy (1997)