Garage doors form part of the external wall which maintains the temperature inside the home, but not all garage doors prioritize insulation in their design. The insulation of the panels, the ability to prevent leakage, and overall quality in construction are the keys to buying an energy efficient garage door.
Understanding the R-value
An R-value is an engineering term describing how materials resist heat flow, or specifically heat loss or heat gain. The metric version is called an RSI; the higher the value, the better it is at insulating. There are a number of factors contributing to how well something insulates heat, common strategies include using materials that create multiple small pockets of air or materials that are smooth and shiny to reflect heat.
Evaluating a door for its leakiness
With any door or window the escape of air leads to changes in heating and cooling, which is why the detection of drafts is such a common concern in older homes. Sealing a garage door is similar to sealing any other opening: weather stripping provides a cushion that closes the gap between the door and its jamb. All things being equal, should a garage door with only a single panel perform better than a sectional one? The answer takes into account these factors:
- The average r-value of a sealed section compared to the r-value of the material of the garage door
- How the sealant holds up to wear and tear
- Checking for a consistent seal around the sides as well as between the sections
Even measuring the amount of air leakage can be tricky, so it’s difficult to say which style is better for energy use. Over the long run, roll-up garage doors are less likely to fail than tilt-up ones, so if you use your garage frequently (like parking your car indoors at night), it’s more cost-efficient to get a standard sectioned garage door.
Choosing between wood and steel
When choosing between doors, given even thicknesses, the materials perform in this order:
- Insulated steel
- Glass, aluminum and vinyl
Insulated steel uses polyurethane or polystyrene as a filling; the steel thickness ranges from 24 to 28 gauge in thickness.
In addition to looking at your garage door as a way to save on energy use, it’s also worth noting that the door leading to the garage needs to be well-insulated.