We will make a comparison between a 12” x  24” CARDBOARD
filter and a 12” x 24” CENTEX METAL filter:

Here is the CARDBOARD Filter:


See the Cardboard fingers criss-crossing through the “Air-Flow” plane? We will take those out of the filter!

We want to see if they impede the air-flow coming from your air-conditioning or heating equipment! Stopping or slowing the air from coming through a filter may:

1. Place a drain on your equipment motor until the motor finally stops running. A huge equipment cost!
2. Which would possibly make the wires warm enough to finally crystallize and short out.
3. Not let the air come through the filter freely to cool or heat the area for which the equipment was designed.
4. Throwing your good money away!

We are going to remove the cardboard fingers:

We did number the fingers numerically to be sure we had all of them:  We cut them and laid them out to show the area of air they are redirecting, impeding, or stopping altogether.  We found that a large portion of the filter was simply not used to its full capacity--that in a 12” x 24” cardboard filter there was only air space (without the fingers) of 10” x 22” = 220 sq. in.

With the fingers in place there is:

Only 10” x 14.25” which is only: 142 sq. in.
More than 1/3 of the total area is wasted: 78 sq. in.

That means also that more than 1/3 of your money is wasted!

Now when you buy a metal filter, there is only a frame cost ONE TIME!  It Stays with your unit until the unit is replaced!

After that the only cost is the filter material which is sent to you automatically After a period of a few months, you are actually Saving Money!

CENTEX METAL FILTERS actually provide more Air-flow area than the cardboard filter:

A 12” x 24” metal frame gives an Air-flow space of  10.5” x 22.25” with 100% Air-flow area which:

1. Lets the unit motor run freely with no drag; no strain on the electrical system--no hot wires!
2. Gives you 100% heating or cooling for your money spent!

Our Metal Frame VS Cardboard Frame:

Frame Information Our Metal Frame Cardboard
Size Stamp of Edge of Frame 12” x 24” 12” x 24”
Actual Frame Size 11 ¾” x 23 ¾” 11 ¾ x 23 ¾”
Frame Area for Free Air Flow 233.625 Square Inches 142 Square Inches
Actual Air Flow Space 233.625 Square Inches Less than 142 Square Inches
Actual Percentage of Air Flow 100% Less than 67 ½ %


One time purchase only Metal Frame and receive 100% of the Air Flow capability instead of continually buying Cardboard Frames which give only 67 ½% Air Flow capability and which can impede the Air Flow and can damage your equipment by unnecessary strain on the motor and wiring.