The process for how to measure for storm windows is similar to finding measurements for single or double hung windows.
How to measure for replacement windows in brick house.
Replacing metal windows in brick homes.
Then take a tape measure and measure between the vertical legs of the casement across the top and in the middle and at the bottom of the opening.
To find the width measure jamb to jamb from the inside of the trim on one side of the window to the inside of the trim on the other side.
All casement angles should be a flush 90 degrees.
To measure for replacement follow the same three step measuring guidelines but strike the tape from brick to brick to measure the window s width.
To find the height measure from the sill to the inside of the trim at the top of the window.
To determine height measure from the brick at the bottom to the lintel at the top of the opening.
Measure at the bottom middle and top of the window.
Record the shortest measurement as the width.
Again you ll need to take three measurements each extending from the top horizontal board.