Radiant Barrier vs More Insulation: What Works Best Under an Oklahoma Roof?

If your Oklahoma City attic has less than about 10 inches of insulation, add insulation first. Insulation slows heat in summer and winter. A radiant barrier mainly helps in summer, and it gives the most benefit when insulation is already at R-38 or more and ductwork runs through the attic.

What a Radiant Barrier Does

A sunny roof deck gets much hotter than the outside air and radiates heat down onto everything in the attic. A radiant barrier is a reflective foil that blocks most of that radiant heat. It does not have an R-value the way insulation does, and it does little in winter.

What More Insulation Does

Insulation slows all heat flow through the ceiling, all year. In an attic with thin, settled insulation, adding depth with blown-in insulation is almost always the bigger and cheaper improvement.

When Each One Wins

• Insulation first: attics under about R-30, visible joists, settled or patchy insulation
• Radiant barrier next: attic already at R-38 or more, ducts or an air handler in the attic, sunny roof with little shade
• Skip the barrier: heavily shaded roofs, or attics with roof deck spray foam

Install It the Right Way

Radiant barrier foil works best stapled to the underside of the rafters, with the vent path from soffit to ridge left open. Laying foil on top of floor insulation lets dust build up and cut its reflectivity, and solid foil there can trap moisture.

Cost

Rafter-installed radiant barrier typically runs about $0.60 to $1.50 per square foot of roof deck, or about $1,200 to $3,000 for a 2,000 square foot roof deck. Blown-in insulation runs about $1.25 to $2.50 per square foot of attic floor.

Attic Insulation Elite offers free attic inspections and written quotes seven days a week, 8am to 8pm. Call (405) 400-2050 or request a free quote online.