Retrotec USACE - Manual (Page 141)

Appendix D D11
D.1.4 Windows
D.1.4.1 Single-Pane Windows with Frames Having No Thermal
Breaks (Waste)
Figure D17. Examples of single-pane windows with metal frames that create thermal ridges.
Single-pane windows result in excessive heat losses and gains due to the overall
windows low R-value. Such clear-glass windows offer no solar heat gain pro-
tection. Original aluminum or metal framed windows have no thermal break,