Our Products’ Performance Speaks For Itself! 

All windows have similar components, frames, glass, and hardware.  What sets the H Window apart from plastic vinyl, composite, wood/aluminum clad, or fiberglass frame windows, is its unmatched overall performance.

The H Window windows and doors thermal performance is unmatched among almost all commercially rated windows. Although very important, the U-value/factor is only one standard of performance.

The H Window

Measurements of Performance

Besides U-value/factor, the other important measurements of performance are:

  • Air Infiltration
  • Water Infiltration
  • Window Design Pressure
  • Condensation Resistance
  • Sound Control
  • Forced Entry Rating (Security)


The H Window’s U-factor can be as low as .20(R-5) for the direct set (fixed) and .28 for both of the H Window’s operating window systems (awning and casement). Click here to see PERFORMANCE TABLES & Comparison Chart.

Air Infiltration/Leakage 

The H Window’s awning window outperforms the competition in performance tests. No operable window seals tighter. In fact, H Window scores better on the 50 mph air infiltration windows test than most windows can at 25 mph, not just in the lab.   We set our benchmarks in real-world tests on installed windows.  High performance is due to the design of the hinge, which allows an uninterrupted perimeter seal, meaning that the harder the wind blows, the tighter the H Window becomes.
Click here to compare the H Window versus:
Wood Clad Double Hung Window
Clad Wood Casement Window

Water Resistance 

Random field-testing demonstrates that the H Window can pass a 25 pounds per square foot water test. This performance rating is equivalent to 8 inches of rain per hour at a 100 mile per hour wind pressure. 

Design Pressure

Structural wind test exceeds 240 miles per hour, and that’s more than twice the window industry’s normal ratings.  

Condensation Resistance

The H Window’s rating with standard dual glazing receives a 67. The NFRC has developed a standard method for determining the possible formation of condensation.   The ratings range from 1 to 100. The higher the score, the better a window’s resistance to condensation. Most window manufacturers do not disclose their condensation resistance rating. 

Sound Control  

The H Window receives a 28-46 STC rating, depending upon the glazing options.   Sound Transmission Class ratings are based on how much noise reduction occurs through a wall, window, or partition. The window industry standard for most dual and some triple glazed is an STC rating of 26.

Forced Entry Rating (Security)

This rating refers to the resistance the window or door has to frustrate a forced entry.   The ratings vary from 10-40, with 40 being the highest rating possible. The industry standard is 10. The H Window receives a 40 rating.

Other performance factors/data to be considered are Solar Heat Gain Coefficient (SHGC) Visible Transmittance (VT). These ratings vary based on the choice of glass that is selected.