How to Insulate a Window with Sash Weights

In this video, This Old House general contractor Tom Silva explains how to insulate a window with sash weights.

Steps for Insulating a Window with Sash Weights

1. Use a hammer and pry bar to remove the molding from around the window.
2. Cut a strip of foil-faced rigid foam insulation to fit snugly into the space between the side jamb and plaster or drywall.
3. Spray some maximum-expanding polyurethane foam sealant into the space at the bottom and top of the window’s side jamb.
4. Press the strip of foil-faced insulation into place alongside the side jamb, flush with the wall.
5. Repeat the above procedure for the opposite side jamb.
6. Cover the seam between rigid foam insulation and the wall with adhesive-backed foil tape.
7. Plug the hole where the rope meets the pulley with a small strip of rubber carpet padding.
8. Replace molding around the window.

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