DASMA TDS 196 - U-Factor Ratings and the DASMA Thermal Performance Verification Program

Garage door manufacturers publish R-values and U-factors on their marketing materials. Some of those numbers come from independent tests; others are calculated estimates. DASMA TDS 196 explains how to tell the difference and why it matters for energy code compliance.

What this data sheet says

DASMA TDS 196 introduces the DASMA Thermal Performance Verification Program, a third-party validation program for garage door U-factor and R-value claims. To participate, a manufacturer submits door models for testing under ANSI/DASMA 105, the standard test method for thermal transmittance (U-factor) and air infiltration of garage doors.

"The DASMA Thermal Performance Verification Program provides independent confirmation of a manufacturer's published U-factor values through third-party testing under ANSI/DASMA 105."

The TDS explains the difference between a verified thermal label and a self-declared one:

• Verified label: the U-factor was measured by an accredited laboratory using ANSI/DASMA 105. The result may appear on the door with a DASMA seal.
• Self-declared R-value: the manufacturer calculated or estimated the insulation value from the foam core material properties alone, without accounting for thermal bridging through the steel skins, hinges, and panel joints.

The TDS also explains why R-value and U-factor measure different things. R-value measures the thermal resistance of the insulation material itself. U-factor measures the overall rate of heat transfer through the entire door assembly, including edge effects and air infiltration. For whole-assembly energy performance, U-factor is the more complete and accurate metric.

When it applies

Energy code compliance in Denver and Colorado references the International Energy Conservation Code (IECC). The IECC uses U-factor as the performance metric for fenestration and doors in certain compliance paths. A garage door U-factor verified under ANSI/DASMA 105 can be used directly in an IECC compliance calculation.

Homeowner energy comparisons are also served by TDS 196. When a homeowner compares two doors marketed at "R-18" and "R-16," those numbers tell only part of the story. A DASMA-verified U-factor label tells the whole story: total heat flow through the full assembly under real test conditions.

In Denver, with ground snow loads of 43 psf and cold winters, the garage is often an unheated buffer zone between the conditioned house and the outside. A well-insulated garage door reduces heat loss through that buffer, which can reduce heating bills and make the attached garage more comfortable.

What this means for you

Look for the DASMA thermal label, not just an R-value claim. The label indicates third-party verification. An R-value stated only in marketing materials has not been independently tested under ANSI/DASMA 105.

For IECC compliance submittals, use U-factor, not R-value. If a permit submittal requires documentation of the door's thermal performance, provide the U-factor from a DASMA-verified test, not a converted R-value.

Lower U-factor is better. A U-factor of 0.20 allows less heat to pass through than a U-factor of 0.35. For a heated garage or a garage directly adjacent to conditioned living space, the difference in annual heat loss is meaningful.

G Brothers can provide DASMA thermal-verified door options and documentation for energy code submittals in Denver and across the Front Range.

Full text and source

Download DASMA TDS 196 from the official TDS index at https://www.dasma.com/technical-data-sheets/.

This entry covers the DASMA Thermal Performance Verification Program for residential garage doors. Commercial insulated doors may use different test standards and certification programs.

Want to put numbers to this? Use the interactive roof snow load calculator below, or open the full roof snow load calculator with examples and notes.