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Insulation for an Air Conditioner Drainage Pipe

Andrew Leahey

Air conditioner drainage pipes carry condensate from the condensation pan away from the air conditioner and dump the water outside the home. There are a few points in this system that might require insulation and are worth considering. The first is the pipe itself. Containing water that is cooler than the ambient temperature in your attic, the pipe can sweat or accumulate condensation of its own. Second, the hole where the condensation drain exits the home can allow air to flow back into the attic and may need insulation.

Pipe Sleeves

Central air conditioners dump hot air and condensation outside the home.

If your condensation drain is PVC or copper and of traditional 1- or 1 1/2-inch size, commercial pipe sleeves are available at many hardware stores. They are typically gray and made of Styrofoam, which will serve to insulate the pipe from the hotter temperatures in the attic and prevent condensation accumulation and water damage.

Rubber Coating on Pipe

There are third-party products made of rubber, sold under the brand name Rubatex, that can be wrapped around condensation drainpipes to prevent sweating. They typically come in rolls similar to duct tape and should be wrapped around the pipe from the air handler to the point where the pipe exits the attic.

Drain Hole

Insulate the area surrounding the drain hole, where the condensation pipe exits the attic, using a few commercial products. Polystyrene expanding foam insulation products can be sprayed into the opening and allowed to expand to form an air- and water-tight seal. In a pinch, silicone caulking around the circumference of the pipe will work well to keep the elements out of the attic.

Condensation Drain Trap

In the condensation drainpipe there should be a small elbow, called a trap. This trap remains filled with water and prevents air from traveling from the outside of your home through the drainpipe and into your attic. Ensure this trap is properly installed and functioning properly to avoid not only air leaks but also potential condensation drain malfunction.