Interior storm windows are custom built to ensure a tight fit. Sizes are
determined by measuring your existing window opening.
• Measure opening width at three locations (top, center, bottom)
• Measure opening height at three locations (right, center, left)
• Round the narrowest width and the shortest height down to the nearest 1/16" and provide these dimensions when ordering; window panel is downsized to fit opening given.
NOTE: 1" inch depth is recommended for installation of the LARSON Insider Storm Window. For out-of-square openings, 1/8" tolerance.