U-Factor and Solar Heat Gain Coefficient

Title 24, part 6, of the California Code of Regulations, sets energy efficiency standards for residential and non-residential buildings. If you’re building a new home, you should consider buying the most energy-efficient doors possible. When selecting doors for energy efficiency, it’s important to consider their energy performance rating concerning the local climate.

Look for a low SHGC in a climate that mainly requires cooling and a high SHGC in a climate that requires heating. The range is from 0 to 1. SHGC measures how well a product keeps out solar heat. Look for a low U-factor; the range is from 0.00-2.00. The lower the U-factor, the better the door keeps in heat.

The newly updated California code for residential fenestration requires U-factor ratings of 0.30 or better and Solar Heat Gain Coefficient (SHGC) ratings of 0.23 or better.

Benefits of Argon Gas in Windows

Almost all thermal windows today use some type of gas fill, so the benefits of argon are similar for most new thermal windows.

  • Improves U-value, the measure of a window’s thermal performance; similar to the R-value of wall insulation
  • Enhances soundproofing characteristics
  • Minimizes heat exchange through the window
  • Reduces the possibility of condensation and frost
  • Can be used in all climates
  • Can be combined with low-E coatings for optimal window performance
  • Available in residential and commercial window sizes and styles
  • Does not corrode window material as oxygen will
  • Does not contaminate the environment; non-toxic gas