Blown-In Insulation Calculator
Loose-fill is sold by the bag, and each bag covers less area the deeper you blow it. Enter your area and target R-value to get the bag count, settled depth and cost.
Your project
Covers cuts, compression and odd bays. 10% is the usual default.
Your results
- Bags required
- 54 bags
- Coverage per bag
- 24.5 sq ft at R-49
- Settled depth
- 14.4 in
- Estimated material cost
- $1,296
- Blower rental (1 day)
- $110
- Pro installed estimate
- $2,291
Often waived with a minimum bag purchase
Estimates use typical US material and labor pricing. Confirm quantities against the coverage chart on the bag before you buy.
Gear for this job
Blown In Cellulose Insulation
Owens Corning R-19 Unfaced Fiberglass Insulation 77.5 Sq.ft (15 in x 93 in) 1 Batt
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Attic Measuring Rulers (Case of 400), 20 Inch, Card Stock, Attic Insulation R-Value Ruler for Insulators Ceiling Insulation
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DGSL Double Reflective Bubble Foil Insulation Foam, 23.6 in X 10 FT Aluminum Foil Thermal Insulation Radiant Barrier for Window, Garage Door, RV, Roof
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Insulation Blower Machine Rental
PSI Woodworking DC3XX 1.5 HP Portable Dust Collector Motor Blower
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VIVOSUN Double Bubble Foil Insulation Roll, 6" x 25 ft Reflective HVAC Pipe & Duct Wrap, Weatherproof Thermal Insulation for Attics, Windows, Garages
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Dayton 1TDP3A Round OEM Blower with Flange
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Attic Ventilation Baffles
36 Pcs Attic Insulation Baffles for 24" Rafter Bays, 2" Air Channel | Black Polyethylene Rafter Vents,Improve Roof Ventilation,Prevent Insulation Blockage,Hassle-Free Installation
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UDV2248 Durovent Foam Attic Rafter Vent (Pack of 70) by ADO Products
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30 Pack 24 Attic Insulation Baffle, Sturdy Polypropylene Attic Baffles for 24" On-Center Rafter Bays with 2" Air Channel, Improve Roof Ventilation and Prevent Insulation Blockage
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How this calculator works
- Bags = (target R × area) ÷ bag coverage rating
- Coverage per bag = bag rating ÷ target R
- Settled depth = target R ÷ R-per-inch
Frequently asked questions
Cellulose or blown fiberglass?
Cellulose packs a bit more R per inch and blocks air movement better; fiberglass is lighter, won't absorb water, and won't settle as much. Both perform fine when installed to the depth on the bag.
Do I need to rent a blower?
Yes for anything over a small area. Most big-box stores lend the machine free when you buy enough bags — usually 10 to 20.
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Bags required
54 bags