According to the International Association of Certified Home Inspectors, fiberglass and foam insulation materials will last a lifetime, provided they are not punctured, cut, or burned and kept dry and away from UV rays. This is true regardless of whether the installation was loosefill, housewrap, or batts/rolls.
Certain conditions can significantly affect the quality and effectiveness of your home’s insulation. One of the most common causes of insulation degradation is water damage. Leaks in roofs or the foundation can cause the insulation to gradually degrade over time as the water breaks down the material. Moisture from leaks can also cause mold growth, which makes insulation less effective and even harmful. Over time, loosefill insulation may settle, resulting in air leaks. Cellulose or fiberglass batt insulation also tends to fall from ceilings or crawl spaces just 15 to 20 years after installation. Regular dirt and dust can also impact the effectiveness of your home’s insulation.