Is an insulated garage door worth it in Georgia's heat?

The U.S. Department of Energy describes R-value as a material's ability to reduce heat flow between inside and outside. The greater the R-value, the more heat flow is reduced.

On a garage door, DASMA's technical data sheet 163 adds an important limit. A door R-value is a calculation for one door section: the outer skin, the foam core, the inner skin and the air films on each side. It does not account for section joints, stiles or seals, and DASMA says it should not be used to describe the full door assembly.

DASMA's alternative is U-factor, which is tested on a complete, installed door in a lab under the ANSI/DASMA 105 standard. Lower U-factor means better insulation. DASMA says the two numbers come from different methods and are not reciprocals of each other, so you cannot convert one into the other.

DASMA's publishing guidelines say a manufacturer's R-value should carry a note that it is estimated under TDS-163 and that actual R-value may vary. If a door lists a tested U-factor, that number reflects the whole door you will live with.

Clopay says insulation helps attached garages in particular, because heat moving through an attached garage can affect the living spaces next to it. For a detached garage in a mild climate used only for parking, it says a lower R-value or a non-insulated door is often enough.

If there is a bedroom over your garage or a shared wall with the kitchen, that is the attached-garage case.

NOAA's 1991 to 2020 climate normals for Hartsfield-Jackson put the average June to August high at 88.7°F and the average summer temperature, day and night, at 79.6°F. The station averages about 47 days a year at 90°F or above.

Clopay describes a non-insulated door as a single layer of material, and an insulated one as two or more layers with insulation between them. It says a single-layer steel panel dents on contact, while an insulated door is more resistant to dents and dings and dampens more sound.

The two common cores: polystyrene, which Clopay calls a budget-friendly choice, and polyurethane, which is foam-injected between the layers and expands to fill the gaps.

We do not quote energy savings for a garage door. We have not found an independent, published savings figure for garage doors in Georgia, and the Department of Energy's insulation guidance covers attics, walls and floors, not garage doors. We can show you each door's published R-value or U-factor and explain what it covers. Book a free measurement through the new door quote form.