As cooler weather settles into Fresno, homes begin to close up tight to keep the warmth inside. While that keeps your heating system running efficiently, it also traps air indoors—along with the allergens, dust, and pollutants that build up during fall and winter. At Purl’s Sheet Metal & Air Conditioning, we know that maintaining good indoor air quality (IAQ) is essential for your comfort, health, and overall system performance throughout the heating season.