The value option for open attics
Blown-In Insulation in Washington, DC
Seal the leaks, then blow in loose fill to the depth the attic needs.
- Free on-site estimates
- Written quote listing material, thickness and R-value for every area
- Moisture and ventilation checked before anything is sealed up
Where Loose Fill Beats Foam
Blown-in insulation is often the best value for an open attic floor. Loose cellulose or fiberglass is blown through a hose and settles into an even blanket, filling around joists and wiring. Where there is room for depth, it reaches high R-values for less money than foam.
Cellulose vs fiberglass
HomeGuide lists blown fiberglass at about R-2.2 to R-2.9 per inch and cellulose at R-3.1 to R-3.8. Cellulose packs more R-value per inch and slows air movement a bit more; fiberglass is lighter. Fixr puts fiberglass at $1.65 to $2.60 per square foot and cellulose at $1.75 to $3.80.
Air sealing comes first
Loose fill does not stop air. Before blowing, we seal top plates, stacks, wiring holes and the hatch. Otherwise hot attic air in summer and warm house air in winter keep moving through the new insulation.
How deep
ENERGY STAR suggests R-60 for an uninsulated Zone 4A attic, or R-49 added over 3 to 4 inches. That means more than a foot of loose fill.
Suburban attics
Many 1950s-1970s colonials, ramblers and split-levels in Montgomery, Prince George's, Arlington and Fairfax have walk-in or hatch-access attics with a few inches of old insulation. Sealing and topping up is often the single best upgrade in those houses.
Rowhouse roof cavities
Where a rowhouse roof cavity has enough depth, blowing loose fill through a roof hatch or small ceiling opening can fill it without opening the ceiling. We check depth, access and any wiring first.
Top-up over existing insulation
If the existing insulation is dry and clean, we seal the bypasses we can reach and then add loose fill on top to reach the target R-value. The quote shows how many inches will be added.
Blown-In Options
Materials and where we use them.
Blown cellulose
Higher R per inch, slows air a bit more.
Blown fiberglass
Lighter, resists settling.
Top-up over existing
Adding depth over dry, clean existing insulation.
Dense-pack walls
Cellulose blown at high density into closed frame walls.
Published Blown-In Insulation Costs
| Job | Range and source |
|---|---|
| Blown-in, per sq ft | $1.00 to $2.80 (HomeGuide); $1.65 to $3.80 (Fixr) |
| Attic | $900 to $3,600 (HomeGuide); $1,750 to $5,500 for about 1,500 sq ft (Fixr) |
| Exterior walls | $1,900 to $7,800, $1.10 to $3.70 per sq ft (HomeGuide); $2,000 to $4,000 (Fixr) |
| Dense-pack cellulose | $1.60 to $4.20 per sq ft (HomeGuide) |
| Fiberglass / cellulose | $1.65 to $2.60 / $1.75 to $3.80 per sq ft (Fixr) |
| Typical job | $800 to $3,000 (HomeGuide); $3,000 to $7,000 (Fixr) |
From HomeGuide (Nov 2025) and Fixr (Aug 2025), national figures. Depth, access, air sealing and any removal change the total. The price is the number on your written estimate.
How a Blown-In Job Goes
1. Inspect
Depth, condition, bypasses, ventilation.
2. Quote
Sealing and insulation lines with target R-value.
3. Seal and baffle
Close bypasses, install baffles.
4. Blow to depth
Even coverage with depth markers.
Why Choose Us for Blown-In Insulation
Sealing included in the plan
Never blown over open bypasses.
Depth markers
You can check the depth.
Clean work
Hose run and house protected.
Blown-In Insulation Questions
Is blown-in or spray foam better for my attic?
For an open attic floor with room for depth, sealed and blown-in is usually the better value. Foam earns its cost in tight spaces and roof decks.
How much does blown-in insulation cost?
HomeGuide lists $1.00 to $2.80 per square foot and $900 to $3,600 for an attic. We quote after measuring.
Can you add insulation over what I have?
If it is dry, clean and not hiding leaks we need to seal, yes.
Does blown-in settle?
Loose fill settles some over time. We install to account for it and leave depth markers.
Blown-In Insulation Service Areas
- Spray Foam Insulation in Washington, DC
- Spray Foam Insulation in Capitol Hill, DC
- Spray Foam Insulation in Georgetown, DC
- Spray Foam Insulation in Petworth, DC
- Spray Foam Insulation in Silver Spring, MD
- Spray Foam Insulation in Takoma Park, MD
- Spray Foam Insulation in Bethesda, MD
- Spray Foam Insulation in Rockville, MD
- Spray Foam Insulation in Hyattsville, MD
- Spray Foam Insulation in College Park, MD
- Spray Foam Insulation in Bowie, MD
- Spray Foam Insulation in Arlington, VA
- Spray Foam Insulation in Alexandria, VA
- Spray Foam Insulation in Falls Church, VA
- Spray Foam Insulation in McLean, VA
Get a Blown-In Insulation Estimate
Tell us how the attic is accessed. We will measure and quote.