Overview
A closed shutter adds a barrier and an air space in front of the glass. The result depends on the window, frame fit, blade position and the rest of the building. Use the covering with the season rather than relying on a single insulation claim.
How the extra layer helps
The shutter forms a barrier and an air space in front of the glass. Its effect depends on the glazing, fit and how the blades are used; it is one part of the window's overall performance.
Fit affects performance
Large perimeter gaps or poorly aligned panels reduce the benefit of the covering. Use a suitable frame and adjust the installation so it closes as intended without forcing the panels.
Use shutters with the season
Cover the window during strong summer sun and cold nights when that helps the room. Open the blades or panels when you want daylight, ventilation or useful winter warmth.
