Let’s compare. 1️⃣ Air Sealing Spray Foam:  Expands and seals air gaps Fiberglass:  Does not stop air movement In Toronto winters, air leakage is the #1 cause of heat loss. Winner: Spray Foam 2️⃣ Moisture Resistance Closed cell spray foam: Acts as vapor barrier Prevents condensation Reduces mold risk Fiberglass: Absorbs moisture Can grow mold Loses R-value when wet Winner: Spray Foam 3️⃣ R-Value Per Inch Closed Cell Spray Foam: ~R6 per inchFiberglass Batt: ~R3–R3.5 per inch F