It’s worth knowing that adding thickness to the foam makes a much bigger difference in insulation than increasing the foam density. For example, moving from a 4–2″ taper to a 5–3″ taper boosts the insulation value by about 33%. By comparison, going from a 1 lb. to a 2 lb. density foam in the same 4–2″ taper only improves insulation by about 7–10%.
What is more energy efficient buying thicker cover (going from a 4” x 2” to 5” to 3”) or buying a cover with a higher density foam (going from 1.5lb. to a 2.0lb. density)?
