Alternatively you may measure an existing storm window and order the window tip to tip.
How to measure for exterior storm windows.
Insert your storm windows into the opening and tightly against the window sill.
When ordering give width first then height.
Insert the storm windows.
Specify if the casing is eastern or western.
Leave about 1 8 inch gap at the top of the storm window to allow the window to expand with the temperature.
Measuring 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.
Make sure position the window straight.
Determine if window casing is eastern see 4a or western see 4b.
Step 1 measure width begin by measuring the width of the window inside of the frame.
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.
You ll need to do the following.