Winsert instructions

Making "winserts" (winter insulated window inserts)
Method by Brian Nugent
NOTE: More detailed instructions will be available later in the winter. In the meantime, clicking on the underlined links will take you to some photo illustrations that should help to clarify the construction method.

Principle: The winsert uses two closely-spaced sheets of plastic to create a layer of “dead air” next to your window which keeps warm air from the building from moving out to the colder air outside. While a single layer of plastic sheeting can help reduce heat loss from your windows, it does not usually create this insulating layer of dead air. We believe that a properly-constructed winsert can reduce heat loss from a window by up to 50%. The design was inspired by a long-forgotten FEMA website and has been adapted by North Quabbin Energy members and participants in our workshops. We hope you will feel free to improve it further or adapt it to your particular needs

Materials:

1" pine strips (if you aren't able to find pre-cut strips, you will need to rip 1x6 pine boards into strips of approx. 1 1/4")
water-based sealer
wood glue
heat-shrink plastic
double-sided tape
plastic for pull-tabs
1/2" foam tape

Tools:

tape measure
hair dryer
knife
finish nail gun with 2" brads OR glue corner biscuits OR drywall screws and electric screwdriver
staple gun or small nails for attaching plastic tabs

Step 1: Measure the interior dimensions of your window(s).

Step 2: Cut the pine strips to fit. Make two side strips the height of the interior dimension (subtract 3/4" for the foam tape) and three strips the width of the interior dimension (subtract 3/4" for the foam tape and also subtract twice the width of your wood strips).

Step 3: Assemble the frame pieces. Use a bit of wood glue to hold the pieces together while you position them. Position the middle cross-piece so that it will be in the same place as the frame piece running across the middle of your window. Use drywall screws to fasten the pieces together. Check the squareness of the frame by measuring each diagonal to make sure they are the same length; adjust as necessary. Staple a piece of furring strip to the frame to keep it square while you apply the plastic.

Step 4: Apply water seal to the outside edge and both faces of the outer pieces of the frame.

Step 5: Apply double-sided tape to the frame. Run the tape around the outer edge of the face of one side of the frame. (Remove the furring strip before doing this step.)

Step 6: Cut the vinyl and lay it on a very clean, flat surface, holding it around the edges with clamps. Fasten it to the tape, pressing it firmly in place and trimming off any wide excess, then heat-shrink it in place with the hair dryer and carefully cut off the excess plastic around the edges.

Repeat Steps 5 and 6 for the other side of the winsert.

Step 7: Cut two small pieces of plastic strip and fasten them to the bottom edge of the frame.

Step 8: Apply foam tape around the outside edge. Make sure not to pull too tight around the corners - leave a bit of slack.