Achieve a high-performance door: innovative thermal solutions can enhance U-factor performance in larger doors
By Stephen Aki for Window and Door Magazine
By strategically incorporating advanced materials and innovative design, door systems can enhance energy efficiency, contribute to sustainability goals and ensure compliance with the stringent standards set by modern energy codes.
In the changing landscape of residential construction, the evolution of building codes reflects a continuous commitment to enhancing thermal efficiency of homes. For example, the California Green Building Standards Code, Title 24, sets more stringent benchmarks affecting residential buildings, including new requirements for high-performance fenestration products. Title 24 requires windows and doors with a U-factor of 0.30 and a solar heat gain coefficient of 0.23 in most climate zones.
Meeting U-factor performance
This pursuit of lower U-factors aligns with sustainability goals and incentivizes manufacturers to innovate, seeking solutions that provide a competitive advantage and enhance overall system performance. This impacts the specifications for high-end residential homes and the challenges of choosing high-performance fenestration.
As larger doors become more popular, the challenges to meeting U-factor performance become more difficult. Larger doors require materials that are aesthetically pleasing, structurally sound and thermally efficient. Given the need for structural performance, aluminum is typically the material of choice and is highly conductive. Also, larger doors have larger cavities in the frame, which causes the door system to have lower thermal performance as the larger cavities increase thermal transfer via convection; therefore, manufacturers are exploring strategic modifications to help meet the demands of increasingly stringent building codes.
Foam and thermal efficiency
Foam solutions can effectively enhance insulation and reduce heat transfer in large aluminum doors. Attaching foam as part of a polyamide thermal break helps to reduce convection by breaking up air pockets within the frame. It also prevents air leaks and improves the overall energy efficiency of doors.
Foam tape is PVC foam adhered to the polyamide thermal break in the framing system. The type of foam used in this solution is most commonly PVC, but many other polymers can be used at additional costs. Foam tape is an easy addition to the framing system that can be useful to make the jump from a good thermal-efficient system to a great thermal-efficient system.
Like all thermal improvements, using foam in a door frame can contribute to a more comfortable indoor environment by maintaining a consistent temperature. When applied to the legs (or sides) of a thermal break, foam tape helps create more thermally efficient doors.
The benefits of foam in a door frame include:
• Low-cost solution
• No changes to assembly or fabrication
• No additional equipment
• Improved U-factor
• Excellent weathering characteristics
Utilizing a diverse range of verified materials, high-performance door sys-tems are within reach. By strategically incorporating advanced materials and innovative design, door systems can enhance energy efficiency, contribute to sustainability goals and ensure compliance with the stringent standards set by modern energy codes.