The practical difference
R-value describes resistance to heat flow: a higher value means greater resistance for what was measured. U-factor describes heat transfer through an assembly: a lower value means less transfer. For a door comparison, identify the measurement method and the assembly covered; do not compare the two numbers as though they use the same scale.
Ask what the number describes
A value may refer to a material, a section or the complete door assembly. DASMA’s thermal guidance explains the relevance of whole-door U-factor. Request the supporting product information so you know what is being described instead of comparing labels without context.
Keep the configuration consistent
Check whether the information applies to the selected size, construction and glazing. Have the estimate identify the actual offered configuration, rather than a product-family maximum. If the design changes during quoting, confirm that its thermal documentation still matches the final order.
Connect the specification to your goal
Explain whether your priority is comfort during projects, the relationship to an adjacent room or another concern. A door’s thermal figure does not predict the entire garage’s temperature by itself. Treat it as one input to the purchase rather than a promised household energy result.
Your questions
Should I compare an R-value directly with a U-factor?
They are different measures. Ask for like-for-like product information rather than deciding that one advertised number is better because it is larger.
Does the best thermal number settle the whole purchase?
No. Door fit, materials, intended use and other applicable performance requirements remain part of selecting an appropriate assembly.
Does an insulation value establish hurricane performance?
No. Thermal performance and wind or impact suitability need their own applicable product documentation.