How to Measure

How to Measure and Insulate a Drafty Window

Measure the width and the height of each of your windows in inches. Then multiply the width by height in inches and divide by 12 to get the square feet of your window. Multiply by $5.25 to get your approximate cost per window.

If you decide to get your acrylic plexiglass from a local supplier and only need the frame, then measure the height in inches and divide by 12 to get total linear feet. Then do the same for the width. Since there is a left side, right side, top and bottom we need to account for each linear foot.

For example, as mentioned above, if window is 30 x 60 you will need 2 frame pieces of 2. 5 linear feet and 2 pieces of 5 linear feet plus a little extra to cut to size. In this case we would recommend 2 , three foot pieces and (2) 5.5 linear foot pieces for a total of 17 linear feet or $38.25.

Keep in mind the energy savings begin immediately after you insulate your drafty window with Defender 1 or 2. You will see the savings in your first energy bill.

Cost of Defender Interior Storm Windows

A rule of thumb price for Defender 1 & 2 windows including frame and acrylic plexiglass cut to size is $5.25 per square foot. A 30 inch x 60 inch windows is 2.5 feet x 5 feet or 12.5 square feet. At $5.25 per square foot that equals $65.62.

We sell frames by the linear foot at a cost to you of $2.25. In the above scenario you will need a little extra to cut your frame to size or approximately $38.00.

Plexiglass is cut to size as per your specifications. Pricing is $2.80 per square foot or $35.00. Total cost again is approximately $65.00 for the above mentioned window.


Defender 1 – This is for windows installed inside the window jamb. Be sure you have at least ½ of area for frame installation. Measuring opening width and height for each window. Defender 1 allows for imperfect sized windows jambs. If top is wider than bottom you have ¼ inch of error. Provide measurements for larger size.

Defender 2 – This is a flush mount system for windows that do not have ½ inch to attach frame to interior of window jamb. For flush mount measure ¾ inch on both sides and top. Also take into consideration window sills. If you have a window sill, measure from sill up above top of window ¾ inch. If you do not have a window sill, measure up to an additional ¾ inch on all sides.

For example a window that is 30 x 60 inches would be as follows:

  1. Width, 30 inches from opening to opening – would be 31 ½ inches of width
  2. Height with window sill – 60 inch opening would be 60 ¾ inches
  3. Height without sill – 60 inch opening would ad ¾ inch to top and bottom or a total of 61 ½ inch

Ordering Colors – Defender 1 & 2 come in white or brown frames. Frames can be painted to match window or your wall colors. We recommend a light sanding to increase paint adhesion before applying paint coats.

The plastic factory - home of defender insulating windows
» OUR LOCATIONS: 678 Howard Avenue. Bridgeport CT 06605 Tel.: 203-908-3468
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