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Blown In Insulation Calculator

How much blown in attic insulation do I need?

This calculator should be used as an estimating tool ONLY.

To determine the number of bags of blown in insulation needed:

  1. Measure the depth of your existing insulation and enter this number below.
  2. Is your current insulation fiberglass (applied in rolls / batts) or cellulose (loose, sprayed-in material)?
  3. Based on your desired R-value, how many total inches of insulation do you need? (See map for regional recommendations.)
  4. Enter the dimensions of your attic.
  • 1
    • Measure the depth of your existing insulation and enter this number below. in.
    • Current Insulation Type:

      NOTE: Fiberglass insulation can be installed in rolls (called batts) or blown in. Cellulose is loose, blown in material.

    Next Step: Your Desired R-value
  • 2
    • Determine Your Desired R-value.
      Estimated Current R Value:

      See the map below for recommendations for your zone.

      Recommended R-value Range for an Uninsulated Attic
      Zone R-value Range
      1 R30-R49
      2 R30-R60
      3 R30-R60
      4 R38-R60
      Zone R-value Range
      5 R49-R60
      6 R49-R60
      7 R49-R60
      8 R49-R60
      Click to Enlarge R-value Map
    Back | Next Step: Measure
  • 3
    • Enter the dimensions of your attic.
      • ft.
      • ft.
    • Desired Insulation Type:

      NOTE: Fiberglass insulation can be installed in rolls (called batts) or blown-in. Cellulose is loose, blown-in material. Adding rolled insulation on top of existing blown-in insulation is not recommended.

    Back | Next Step: Results