Flat roofs often outperform pitched roofs in energy efficiency due to their more straightforward insulation design. The membrane system used in flat roofs applies insulation sheets directly to the roof surface, providing continuous coverage and fewer gaps compared to the cavity insulation system used in pitched roofs. This results in a more efficient R-value, which measures the insulation's thermal resistance.

Materials like EPDM and light-coloured PVC can achieve substantial energy savings by reducing heat transfer between the outside environment and the house's interior. For instance, EPDM roofs have been shown to lower surface temperatures by 30-40% compared to conventional roofs, resulting in significant energy savings.

The energy savings from flat roof insulation can be substantial. According to the EPA, cost-effective improvements like air sealing and adding insulation can save homeowners a national average of 11% on total energy costs.

In particular climates, this can translate to savings of up to 16% in colder zones and 8% in warmer zones. Additionally, proper ventilation is crucial in flat roofs, as it prevents heat from accumulating in the attic and transferring into the home.

Good ventilation can further enhance the energy efficiency of flat roofs.