Install Insulating Curtains or Blinds

Thermal curtains and insulating blinds add a layer of barrier between the cold window glass and the room interior, reducing heat transfer and blocking drafts that pass through and around the window. Well-fitted thermal curtains can reduce heat loss through windows by 25-40% according to DOE estimates. They also help in summer by blocking solar heat gain. Honeycomb (cellular) blinds trap air in their layered cells and provide insulation values comparable to an additional pane of glass.

Choosing the Right Product

• Thermal curtains: Look for curtains with a dense thermal lining or multiple fabric layers. Floor-length curtains that extend beyond the window frame on both sides seal more effectively than short ones.
• Honeycomb/cellular shades: Double- or triple-cell designs offer the best insulation. Top-down/bottom-up models allow you to control light while maintaining insulation.
• Insulated Roman shades: A middle ground between curtains and blinds, with insulating layers built into a structured shade.

Installation Tips

1. Mount curtain rods as close to the ceiling as possible and extend them 3-6 inches beyond the window frame on each side to minimize air gaps.
2. Use return brackets or wraparound rods so curtain edges sit flush against the wall, preventing air from circulating behind the fabric.
3. For cellular shades, choose an inside mount for a clean look or an outside mount that overlaps the frame by 1-2 inches for better insulation.

Tips

• Close curtains at dusk and open them on south-facing windows during sunny winter days to capture free solar heat
• Velcro strips or magnetic tape along curtain edges can create an even tighter seal against the wall
• Layering sheer curtains under thermal curtains provides daytime privacy while still allowing light