In recent years, spray polyurethane foam (SPF) insulation has seen significant growth in both general interest and acceptance as a high-performance solution to seal and insulate the entire building envelope. SPF insulation is energy efficient, durable, and helps create a comfortable building environment by helping keep homes warm in the winter and cool in the summer. Because it is sprayed directly into the gaps, cracks, and other surfaces that contribute to heat loss, SPF both insulates and air seals, offering an easy and effective way of weatherizing existing buildings and new construction.