Hi I'm in southern indiana and I'm insulating a 10x20 shed for a game room/office, i will have a 12k btu ac and 11k btu heater, it is 2x4 construction. Im planning r15 fiberglass and 3mm radiant insulation for the walls. Would this be enough for the ceiling or should I figure out a way to do higher r-value for the ceiling.

  • Ceilings usually closer to R-40, walls close to R-20. 2x4s plus 2x2s will give space for R-20, only losing 1.5 inch per outside wall. Do you already have the AC/heater? If not, a mini split should save power use.
    – crip659
    Commented Apr 19 at 23:41
  • You live in the climate zone 4-5, Look up what R value do you need.
    – Traveler
    Commented Apr 20 at 2:18

1 Answer 1


If you are in Climate Zone 5 Indiana energy code as of 2020 requires R20, or R13 (between studs) and R5 continuous (sheet over studs) minimum wall insulation, and R30 minimum floor insulation. If you are in Climate Zone 4 it requires R15 minimum wall insulation and R19 minimum floor insulation.

In either zone R38 is the minimum ceiling insulation.

If the floor is a slab, R10 around the perimeter 2 feet deep in either zone.

Greater than minimum insulation will lower your operating cost over the life of the building and also meets code. Code sets only the minimum required amount.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.