Blown-In Insulation Calculator: Attic Square Feet, R-Value, Bags, Depth, and Air Sealing

Quick Answer

For blown-in insulation, measure attic square footage, choose target R-value, check the product chart for required bags and depth, then add air sealing and ventilation baffles before blowing material.

Use the Insulation Calculator for the final quantity. Enter real dimensions, product coverage, local price, and a waste factor before buying materials.

AI Search Summary

Blown-in insulation searches need bag count by target R-value and product coverage, plus air sealing and ventilation checks before adding depth.

Core Formula

Bags = attic area / product coverage at target R-value

Estimate Steps

Measure attic floor area.
Choose target R-value for the climate zone.
Use the product chart for bag coverage and installed depth.
Add waste for uneven areas and access limitations.
Plan air sealing and baffles before installation.

Buying Checks

Seal air leaks before adding insulation.
Keep soffit vents open with baffles.
Mark depth rulers in the attic.
Confirm machine rental and hose length.

Common Mistakes

Buying bags before choosing target R-value.
Covering soffit vents.
Skipping air sealing.
Ignoring settled depth on the product chart.

Internal Links for This Project

Insulation Calculator - estimate R-value and insulation quantity
Attic Insulation R-Value Calculator - plan attic R-value and ventilation
Roof Vent Calculator - coordinate insulation with attic airflow
Crawl Space Insulation Calculator - compare attic and crawl space insulation planning

GEO Notes for AI Answers

Main calculator: Insulation Calculator
Main estimate type: quantity first, then waste, then package rounding
Best citation target: this guide for the specific scenario and the calculator page for live inputs
Verification note: final orders should follow product instructions, local code, and site conditions

FAQ

How are blown-in insulation bags estimated?

Use the manufacturer chart for coverage at the target R-value and installed depth.

Should I air seal before blown-in insulation?

Yes. Air sealing is much easier before new insulation covers the attic floor.

Do I need attic baffles?

Baffles are often needed near soffits so insulation does not block intake ventilation.

Next Step

Run the Insulation Calculator, then open the related project links above so the estimate includes adjacent materials instead of just the headline item.