Final answer:
Vapor barriers should be placed between the drywall and insulation to prevent moisture from degrading the insulation and structure. They are most effective on the warm side in colder climates. Proper placement ensures a reduction in energy costs and maintains structural integrity.
Step-by-step explanation:
The correct placement of a vapor barrier is between the inside covering (drywall) and insulation. The vapor barrier is used to prevent moisture from passing into the insulation and walls, which could result in mold growth and reduced insulation effectiveness. Vapor barriers are typically made of plastic sheeting or foil-faced paper and should be installed on the warm side of the insulation to be effective, which means facing the interior of the house if you are in a colder climate.
Proper insulation and vapor barrier placement work together to minimize heat loss in the winter and to prevent heat from entering in the summer. This results in a more consistent indoor temperature and a potential reduction in heating and cooling costs. Moreover, effective insulation and vapor barrier systems contribute to the overall durability and integrity of a building's structure.