Volume 12, Issue 6 - July/August 2011

Eye On Energy

 

High-Performance Entry Systems
An Open and Shut Case
by David Bryant

Many entry door manufacturers are getting high performance right. From insulating cores and panels to thermal breaks and new materials, advanced technologies are enabling producers to enhance the energy efficiency of doors. But those efficiency improvements hold little meaning if you neglect the rest of the components that make up an entryway.

It’s best to view an entry as a complete system. The more these components complement and reinforce each other, the better the performance of the entry system.

Frames. Next to the door itself, the frame consists of the most physical material in an entry system. Therefore, it is important
to ensure this component minimizes the transfer of heat and cold to a building’s interior.

Thresholds.
The interface where the bottom of the door seals with the threshold is a common area of concern for leakage. Here, a tight door bottom-to-rail seal will help prevent air infiltration and water penetration. Look for thresholds with flat, even surfaces where the sweep meets the rail. Countersunk screws are preferred, as any obstructions or bumps from protruding screw caps or other hardware may deform the sweep and create a leak point.

The ability to adjust threshold height also is an important consideration. Look for thresholds that enable easy adjustments up or down in small increments to ensure a proper bottom-to-rail seal.

Sweeps.
A door’s sweep forms a secure barrier from the elements, but only when it’s in tight contact with the threshold rail. Make sure the sweep provides maximum surface area contact to the rail, and look for designs that encapsulate both the outside and inside edges of the rail for maximum sealing potential.

When selecting a sweep design, also consider whether the door will utilize a three-point locking system with a locking point (bolt) in the bottom of the door. Such locking systems often necessitate cutting through the sweep to engage the bolt, which may create a migration path for water and air.

Finally, don’t forget to address one of the most difficult areas to seal—the top end of the sweep. Due to tight clearances between the sweep and door, it is difficult to ensure a proper seal with caulk. Accessories like self-adhesive sweep pads offer an alternative that fills in gaps and seals the sweep to the bottom of the door.

Corner Pads. One often overlooked entry system component is the corner pad. This small pad mounted at the intersection of the jamb and threshold helps to reduce air and moisture infiltration behind the weatherstrip that occurs as a result of pressure changes—a phenomenon known as the “straw effect.” Look for pads that tuck behind the weatherstrip and alter pressure rather than simply “plugging the straw.” Avoid pads that crimp the weatherstrip, as any damage may accelerate the straw effect.

Glass Inserts. Naturally, adding lites to a door will reduce its insulating value. However, you can minimize this impact by using high-performance double- and triple-pane insulating glass units (IGUs). Choose doors with IGUs that feature high-performance spacers and gas filling, as well as low-E coatings that are appropriate to the building’s location and orientation. Make
sure the IGUs are sealed properly to the door to ensure leak-tight performance.

The Whole Package. Combining the best of the above items with other components lays the foundation for developing an energy-efficient, high-performance entry system. With careful attention to detail, integrated entry system components can provide an effective barrier to air and water infiltration, as well as heat conduction.

David Bryant is senior director of sales for Quanex Building Products’ Engineered Products Group. He can be reached at dcbryant@home-shield.com.


DWM

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