How To Measure For Your PreVent Air Intake Filter Screen

An air intake filter screen protects your HVAC equipment and saves you money, and PreVent® filter screens from Permatron are simply the best filter screens you can buy. In fact, BUILDINGS named the PreVent System a 2018 Money Saving Product winner.

Every PreVent filter screen is custom-made to fit your exact specifications, so be sure to measure carefully. All you need are a pencil, a piece of paper, a tape measure and, if possible, a camera (your phone is fine).

Square or Rectangular Filter Screen Openings

A rectangular or square filter screen is easy to measure. With your measuring tape, measure the distance between the left inside edge of the air intake opening across to the right inside edge. Write down the length and then add 1.25″ to each side of your measurement (so you will add 2.5″ total). This will be the total width of your filter screen, which includes space for your vinyl edge and grommet holes.

For the height of your filter screen, measure from the top inside edge of the air intake opening to the bottom inside edge. Write this down and then add 1.25″ to the top and 1.25″ to the bottom (2.5″ total).

Prevent and MagnaMountSend us your total measurements (height and width, with the 2.5″ added to both). Remember, you will need a flat surface to install your PreVent mount clips to. The center of each grommet will be 5/8 of an inch from the outside of the filter’s vinyl frame. The filter grommets are placed over the mount clip’s moveable tab and locked downward for a secure installation.

Grommets will be spaced evenly every 10″-12″ around the edges. However, some air intake openings have only a small amount of flat surface area around their vents, so there is less room for grommets or edges. Please let us know if this is your situation. Sending us a photo can really help us spot challenges you may not have noticed.

For Filter Screens with Cut Outs for Pipes, Electrical Conduit or Other Obstructions

Send us the total inside height and length measurement of your air intake opening, using the same steps as for a rectangular or square filter screen. Don’t forget to add the additional 1.25″ per side (2.5″ total).

Next, measure the left inside edge of the air intake opening to the area needed for a cut out or slit. Write down that measurement, and add 1.25”. Next, measure the distance from the right of the cut out area to the right inside edge of the air intake opening. Write that down too, and add 1.25″.

You’ll do the same for the top and bottom. Measure from the top inside edge of the air intake opening to the top of the area needed for the cut out. Write that down, and add 1.25″. Next, measure from the bottom inside edge of the air intake opening to the bottom of the space needed for the cut out. Write that down, and add 1.25″.

Lastly, provide the total height and width of the cut-out shape. Sending us this information in a drawing is helpful, which might look something like this:

The area in the example (left) has two circles for pipes, and may be less confusing if this was a single rectangle. If so, the copy in the drawing that reads Pipes: 4″ Diameter would instead read Cutout: 8″ wide x 4″ high]

For Air Intake Openings Without Bottom Frames

Some machines do not have a frame or flat steel surface on the HVAC unit base. A pocket to slip in a weighted PVC will be added instead.

Measure from the ground to the bottom edge of the opening. Write this down. Add 1.25″ to the top, but do not add any additional measurement for the bottom. Instead, let us know that a weighted PVC will be used to weigh down the filter screen. The pocket will hold a 2″ or 3″ PVC.

For Extra Large Units

For extra-large units, more than one air intake filter screen may be needed to make installation and handling easier. Send us your measurements and we will determine if one or more filter screens will work best.

For Irregular Shapes

Some units might have oddly shaped openings, such as triangles. In these cases, you can choose to measure the entire area as a rectangle or square, using the description earlier in this article. Or, you can choose to measure the individual shapes. For example, for triangular screens do the following:

First, measure the bottom of the triangle, from left to right. Write this down. Next, measure from the left bottom, to the top of the triangle. Write this down. Do the same from the right bottom to the top of the triangle. Lastly, measure from the top of the triangle straight down to the bottom center of the triangle, and write this down.

Send us your drawing, which may look something like this:

Unless you notify us otherwise, grommets will be spaced 10″ to 12″ apart along the edges of the triangle.

If you have an air intake opening that’s a different shape than described in this guide, send us a photo. We’re always happy to provide additional instructions on how to make a proper measurement.

Your Space, Our Filter Screen

A Permatron filter screen can be customized for any shape and any size. For more information watch our helpful PreVent measurement video.

The PreVent  system keeps leaves, cottonwood, bugs and other airborne debris out of your HVAC units so they last longer, run more efficiently, and keep your maintenance and cleaning costs down. This can save you thousands of dollars—if not tens of thousands of dollars—every year. One premier beverage manufacturing company cut their HVAC cleaning and maintenance costs by two-thirds after installing the PreVent system. With secure MagnaMount® earth magnets, you can install a PreVent filter screen in minutes, with no drilling or tools. With simple installation, and simply better equipment performance, PreVent filter screens are simply the best.

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