The new Home Energy Rating System (HERS) uses pressure or vacuum created by a fan in a temporary panel in the front door frame.

Some HERS testing companies use only a vacuum to test for leaks. Others use both a vacuum and pressure. Still others use pressure only.

The gravity dampers that are standard with Invisco Whole House Fans will not meet a pressure test for HERS.

If you need to pass the HERS test under pressure, you need to install the Invisco optional motorized damper at the ceiling in place of the standard gravity operated butterfly damper. Be sure to let us know if you need this.

This optional damper is also available as a retrofit for QuietCool whole house fan systems. If you have a QuietCool  system then it is likely to have a gravity operated damper installed up near the fan. It cannot easily be changed into a motor driven damper. The Invisco motorized damper comes with all you need to exchange the QuietCool ceiling box and grille with an attractive custom painted round frame and grille. The damper comes with an AC cord just like the QuietCool system so you can control the damper from the same switched AC you use for the fan.

The same is true for the Airscape Kohilo models of fans that have gravity dampers at the ceiling. You need to change them to motorized dampers to meet HERS pressure testing. Contact Airscape or use our retrofit kit.

Tamarack Technologies has several motorized doors that should meet HERS tests for pressure or vacuum. Tamarack has other models that use gravity dampers and will likely not meet the HERS pressure test. Their HV1450 has a top plate that lifts when the fans go on. It is gravity operated to close and might be heavy enough to withstand HERS pressures but it is advisable to check with the factory.

The Tamarack 1100 and 2200 models use gravity operated doors similar to those used for clothes dryers. Those will likely fail HERS pressure tests without a motorized damper somewhere in the system. Invisco can supply the 10 inch motorized dampers needed to meet the HERS test.

Comfort Cool Fans Company offers 3 systems with excellent motorized dampers. They offer 4 systems with gravity dampers. If you have one of the gravity damper based systems and it  fails the HERS pressure test the Invisco retrofit will solve that.