There are generally three methods for installing Storm Windows that affect the way that they are measured. Those methods are:

-Blind Stop installation (or attaching the storm window into the Blind Stop of the window)

-Overlap installation (or direct mounting the storm window to the outside of the window Casement)

-Window Track Installation (or inserting the storm window into the screen track of the window)

Measuring for a BLIND STOP Installation:

Step 1: Measure the width of the window in three different places, near the TOP, the MIDDLE, and at the BOTTOM. Record the smallest of these measurements for the WIDTH.

Step 2: Measure the height of the window on the left and right. There typically can be two different types of window sills (at the bottom of the window) that can affect the height measurement: DROP SILL and STANDARD SILL.

· For a DROP SILL, make sure to measure to the bottom of the DROP.

· For a STANDARD SILL, you’ll need to measure the height to the highest point on the sill that is in-line with the top HEAD stop.

Step 3: Measuring the Storm Window 'Meeting Rail'

When measuring for your Meeting Rail location, measure from the top of the storm window to the middle of where the two window panels meet.

Measuring for an OVERLAP Installation:

Step 1: Measure the width of the window, and add one inch (1”) to the width to account for the OVERLAP. Record this measurement for the WIDTH.

Step 2: Measure the height of the window on the left and right. There typically can be two different types of window sills (at the bottom of the window) that can affect the height measurement: DROP SILL and STANDARD SILL.

· For a DROP SILL, make sure to measure to the bottom of the DROP.

· For a STANDARD SILL, you’ll need to measure the height to the highest point on the sill that is in-line with the top HEAD stop.

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Step 3: Measuring the Storm Window 'Meeting Rail'

When measuring for your Meeting Rail location, measure from the top of the storm window to the middle of where the two window panels meet.

Measuring for WINDOW TRACK installation:

Measuring for a Window Track installation of a Storm Window is identical to measuring for a FULL WINDOW Screen.

Step 1: Measuring the Storm Window 'Height'

First, check for a TOP TRACK at the top of the window.  The TRACK will be a U-shaped channel that the screen will slide up into.

Next, find the LIP at the bottom of the window straight below the top TRACK. This is what the bottom of the screen will go behind to keep it in place.

The aluminum window shown in the picture above has an inside lip and outside lip (inside for insect screen; outside for solar screen). If yours is similar to the picture sure and find the one on the outside, the 'outside lip'.

This is what the bottom of the storm window will slip behind to hold it in place.

Now that you've located the tracks, let's start measuring!!

Put the end of a metal tape measure all the way into the TOP TRACK you found earlier and hold it downward as straight as possible (the end of the tape measure needs to be small enough to fit all the way up into the TRACK).

Make sure the measuring tape is as far up into the TRACK as possible, see below.

Next, when measuring the HEIGHT, make sure that you measure about 1/16'-1/8' ABOVE the top of the bottom lip, and provide the measurements to the nearest 1/16'.

Take this same measurement on the right side of the window, the middle of the window, and the left side of the window.  Write down the smallest of the three measurements.

This measurement is your Storm Window 'Height'.

Step 2: Measuring the Storm Window 'Width'

Put the end of a metal measuring tape from left to right across the window and hold it as straight as possible.

Place measuring tape on the left side of window opening, as shown below.  Your tape measure should be resting against the part of the window that creates a continuous TRACK up one side, across the top, down the other side and falls behind the LIP at the bottom.

Then, measure to the right side and subtract about 1/16'. You need a little bit of 'wiggle room' in your width measurement so that the screen will be easy to put in and remove.

Take this same measurement at the top of the window, the middle of the window, and the bottom of the window.  Write down the smallest of the three measurements.

This measurement is your Storm Window 'Width'.

Step 3: Measuring the Storm Window 'Meeting Rail'

When measuring for your Meeting Rail location, place the tape measure into the Top Track (as shown above) and measure to the middle of the where the two windows panels meet (called the Meeting Rail).