Yes, drywall keeps heat out, but only to a certain extent. Although drywall is frequently used to construct interior walls, insulation is not its primary function. Each type of construction material has some level of heat flow resistance. The amount of thermal insulation provided by drywall is extremely low. So, you must include insulation while installing drywall if you wish to impact heat transfer effectively. Insulation saves you money by reducing your cooling and heating bills. Spray foam, fiberglass, and loose-fill cellulose are a few insulation materials that complement drywall effectively.