U-factor Calculator for Energy Efficiency

The NABCO U-factor Calculator allows customers to learn the expected U-factor value for a specific project. Validating the U-factor of a standard NABCO Automatic Sliding Door to ensure compliance with relevant Federal, State and Local building codes and individual project requirements.

Please contact NABCO to review your projects’ U-factor requirements, and to properly design a NABCO standard Automatic Sliding Door to meet project specifications, or to learn the U-factor for a specified automatic door.

NABCO Standard GT1175 doors have been tested by an NFRC accredited testing laboratory. Along with U-factor, NABCO can also calculate Solar Heat Gain Coefficient (SHGC) and Visible (Light) Transmittance (VT) given the same information required to calculate U-factor.

What is U-factor?

  • U-factor is the measurement at which a door/window (fenestration system) conducts heat flow, usually expressed in BTU/hr-ft²-°F.
  • It indicates how much energy will be lost from a building through its fenestration system by specifying how many BTU’s can pass through 1 ft² of material in an hour. 
  • The lower the number, the better the door system is at keeping heat in.

Important Calculation Variables

  • Type of glazing and thickness (This is the most important variable)
  • Size and material of the frame structure, spacers, weather stripping
  • Overall area of the fenestration system