What is Blown-in Insulation?

Blown-in insulation is a method of installing loose-fill insulation materials using specialized equipment that blows the material into attics, wall cavities, and other spaces. This technique allows for excellent coverage around obstacles and in irregular spaces where traditional batt insulation would be difficult to install.

Types of Blown-in Materials

Cellulose

R-3.2 to R-3.8 per inch
Made from recycled paper products
Excellent for air sealing

Fiberglass

R-2.2 to R-2.7 per inch
Lightweight and non-combustible
Resistant to moisture and mold

Mineral Wool

R-3.0 to R-3.3 per inch
Superior fire resistance
Excellent sound dampening

Key Benefits

Complete Coverage: Fills gaps and voids that batts cannot reach
Air Sealing: Reduces air infiltration and drafts
Seamless Application: No joints or seams to create thermal bridging
Retrofit Friendly: Perfect for existing homes and hard-to-reach areas

Installation Process

Equipment Required

Insulation blowing machine
Flexible hoses (up to 150+ feet)
Material hopper and agitator
Depth measurement tools

Installation Steps

Seal air leaks with caulk or foam
Install proper ventilation baffles
Set up blowing equipment
Blow insulation to specified depth
Level and verify coverage
Install depth markers for future reference

Installation Methods

Open Blow

• Attic floors
• Open cavities
• Accessible areas
• New construction

Dense Pack

• Enclosed wall cavities
• Existing wall retrofits
• Higher density application
• Better air sealing

Best Applications

Blown-in insulation excels in several applications:

Attics: Over existing insulation or in new construction
Wall Retrofits: Adding insulation to existing walls without renovation
Irregular Spaces: Around wiring, plumbing, and ductwork
Floor Cavities: Between floor joists over unheated spaces
Cathedral Ceilings: In enclosed rafter spaces

Performance Considerations

Density

Critical for performance - too low reduces R-value, too high can compress material

Settling

Properly installed blown-in insulation settles minimally over time

Coverage

Uniform coverage essential for optimal thermal performance

Air Sealing

Provides moderate air sealing but not as effective as spray foam

Professional Installation

While DIY rental equipment is available, professional installation ensures proper density, coverage, and air sealing. Professionals have the experience to achieve optimal performance and can access hard-to-reach areas safely. They also understand local building codes and ventilation requirements.

Cost Considerations

Blown-in insulation typically costs more than DIY batt installation but less than spray foam. The superior coverage and air sealing often justify the additional cost through improved energy savings. Professional installation includes equipment, materials, and labor.

What is Blown-in Insulation?