Curtains or window shades may shield a residential window from heat loss, but may not be a shield against moisture migration. Under such conditions the glass temperature will fall, and the condensation rate on windows will increase. Only a sealed interior barrier will delay the onset of condensation. Thermal barriers on the inside of windows are easy to construct. Moisture barriers are more difficult. In our climate, the triple glazing of windows will become standard — the tightest glazing must be on the inside.