Air Leakage and U-Factor Test Results

A fun first post…

This is a pretty exciting post for me. I have recently joined Freedom Pet Pass as its COO, and in my first blog post I get to show the world our actual energy efficiency test results. As described in a previous post by Brian, our founder and the inventor of DoubleMag™ Technology for pet doors, the testing was performed at the same laboratory that performs tests for Energy Star windows and doors. They tested the same critical parameters (air infiltration and U-factor) that are required for Energy Star certified windows and doors, using the same testing protocols.

The results…

So the results are in. I think the easiest way to look at them is to compare them to something familiar, like an Energy Star door. Remember, for both U-value and air infiltration, lower numbers are better.


Freedom Pet Pass Energy Star Door
Air Infiltration 0.03 cfm/ft2 0.1 cfm/ft2
U-Factor 0.30* Btu/(hr•ft2•ºF) 0.27 Btu/(hr•ft2•ºF)
*The U-factor value of 0.30 is comparing the Energy Star door to the same door with a Freedom Pet Pass pet door in it. The lab-determined “adder” for a Freedom Pet Pass door is 0.03, so the total U-factor for the combination is 0.27 + 0.03 = 0.30. A standalone pet door has a rating of 0.61.

Label from Energy Star Door found at Home Depot

So what does this all mean?

The air infiltration number shows how many cubic feet of outside air will enter through the product per square foot of wall space that the product occupies when under a specific negative pressure. Freedom Pet Pass pet doors all occupy 1-2 square feet of wall space. Compare that to 20 square feet of wall space that a normal door occupies. If you do the math, that means the Energy Star human door leaks 120 cubic feet of air every hour under the harsh test conditions (0.1 cfm/ft2 x 20 ft2 x 60 min). Under those same harsh test conditions, the largest Freedom Pet Pass door only leaks 3.6 cubic feet per hour (0.03 cfm/ft2 x 2 ft2 x 60 min)!

The U-factor value shows the rate at which a window or door conducts heat. It is the inverse of the R-factor used for insulation, so a smaller number is better. The units for U-factor are how many British thermal units (Btu) the product will conduct per hour for every square foot of wall space that the product occupies at a certain difference between inside and outside temperatures. It also assumes a certain wind speed, as that affects heat conductance rate. The standard temperature difference is 70.2°F (inside temp of 69.8°F, outside temp of -0.4°F). If you do the math, you’ll see that the Energy Star human door loses 379 Btu of energy every hour (0.27 Btu/(hr·ft2·°F) x 1 hr x 20 ft2 x 70.2°F). Compare that to the Freedom Pet Pass door, which only loses 85.6 Btu of energy per hour (0.61 Btu/(hr·ft2·°F) x 1 hr x 2 ft2 x 70.2°F).

To sum up a lot of complicated testing and math in one oversimplified sentence, these numbers basically mean that a Freedom Pet Pass dog door or cat door has similar energy efficiency performance to Energy Star rated windows and doors. We’ve put our products through this rigorous testing to prove to you that you can install a Freedom Pet Pass dog door or cat door without sacrificing the comfort or energy efficiency of your house. We hope that you’ll find that useful.


  1. Roger Perrott December 5, 2014 Reply

    Whay not just do away with the heating system and use cats to heat your home?

    • Author
      Donald Love January 10, 2015 Reply

      Okay, that’s pretty funny. As a dorky engineering type, I appreciate both the math and the nerd humor. Well done.

  2. Lee Blanchard December 26, 2014 Reply

    Hi, Congrats for getting good results in air testing. Thanks for this update…

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