What is the recommended practice for duct insulation?

The recommended practice for duct insulation is to insulate ducts that run through unconditioned spaces. This is important because ducts traveling through areas that are not temperature-controlled can lose significant amounts of conditioned air, leading to energy inefficiency and increased heating or cooling costs.

When ducts are insulated in unconditioned areas, they are better protected against temperature fluctuations, which helps maintain the temperature of the air being transported. This not only enhances overall system efficiency but also improves indoor comfort by ensuring that the air reaching the living spaces is at the intended temperature.

In contrast, insulating ducts in all areas of the building may not be necessary, especially if those ducts are located within conditioned spaces where they do not lose heat or cooling. Likewise, not insulating ducts can lead to issues, as unconditioned ducts can cause a drop in system performance and comfort levels. Insulating only the outer sections of ducts would neglect potential heat loss and allow for energy waste in the unconditioned portions of the ductwork. Therefore, insulating ducts specifically in unconditioned spaces is the most effective way to optimize energy performance and maintain comfort.