Which is better for insulating ducts?

The 0.4 in roll. Its closed-cell neoprene, waterproof surface and -4°F to 320°F range suit ductwork better than the thin 0.2 in board, though you will need more rolls for long runs.

Which covers more area?

The 13 x 157 x 0.2 in roll, at about 34 sq ft versus about 6.9 sq ft for the 13 x 78 x 0.4 in roll. For big flat areas it is far cheaper per square foot.

Which is better for sound deadening?

The 0.4 in roll. BXI rates it at up to 18 dB of noise reduction; the thin roll lists no sound figure.

Is the thicker roll worth the extra?

It is actually $4 cheaper: $35.99 versus $39.99 at Amazon as of November 4, 2026. You pay in coverage, not price, so buy it when thickness and specs matter more than area.

Can either be used outdoors?

Only the 0.4 in roll is stated as waterproof, so it is the safer choice for damp or outdoor spots. Neither listing gives a UV rating.

Do both have adhesive backing?

Yes. Both are self-adhesive, so neither needs separate glue for flat surfaces.

BXI Insulation Foam Roll 13 x 157 x 0.2 Inch Self-Adhesive Reflective Thermal Board vs BXI Insulation Foam Roll, 13 x 78 x 0.4 in

Buy the BXI 13 x 157 x 0.2 inch roll if you want maximum coverage for wrapping ducts, walls or large panels: about 34 sq ft for $39.99 at Amazon as of November 4, 2026. Buy the BXI 13 x 78 x 0.4 inch roll if you need thicker, denser foam with a stated temperature range, sound reduction and flame rating: $35.99 at Amazon as of November 4, 2026. The price gap is $4, so pick on thickness and specs, not cost.

Today the BXI Insulation Foam Roll, 13 x 78 x 0.4 in costs $4.00 less at its best price.

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