Blown-in cellulose
Why cellulose is the preferred retrofit material: fire resistance, air sealing, moisture buffering, and environmental profile.
How blown-in cellulose fits in
Insulation slows heat transfer through your home's envelope: attic, walls, basement, and crawlspace. The R-value measures resistance to heat flow — higher is better. Most older homes are significantly under-insulated by modern standards. Upgrading insulation is typically the highest-ROI energy improvement because it reduces both heating and cooling loads, makes heat pumps perform better, and improves comfort. Dense-pack cellulose and rigid foam are preferred for retrofits; fiberglass batts are common but often poorly installed.
This page is part of our insulation guide, written by people who install this stuff for a living. For the full picture — costs, sizing, and every rebate that applies — start from the insulation overview.
What does it cost?
Typical installed costs before rebates. Your actual cost depends on home size, accessibility, and local labor rates.
| Type | Low | High | Notes |
|---|---|---|---|
| Attic insulation (blown-in cellulose) | $1,500 | $3,500 | Most common upgrade. R-49 to R-60 target. |
| Wall insulation (dense-pack cellulose) | $3,000 | $8,000 | Requires drilling and filling wall cavities. |
| Basement / crawlspace (rigid foam) | $2,000 | $5,000 | Rim joist + foundation wall. |
| Spray foam (closed-cell) | $5,000 | $12,000 | Highest R-value per inch. Best for rim joists and cathedral ceilings. |
Run the numbers first.
Free, no account needed. Every figure is cited, so you have a benchmark before anyone quotes you one.
More on insulation
Insulation costs
Cost per square foot by type and location. What affects price: accessibility, prep work, and health & safety.
Insulation rebates
State and utility rebates for insulation upgrades. Many programs cover 40-100% of the cost.
Attic insulation
R-value targets by climate zone, blown-in vs. batts, air sealing the attic floor first, and common mistakes.
Wall insulation
Dense-pack cellulose for existing walls: process, cost, and performance. When exterior rigid foam makes sense.
Basement insulation
Rim joist, foundation walls, and floor insulation. Moisture management is critical.
Spray foam
Open-cell vs. closed-cell, where each is appropriate, health considerations, and cost comparison.
Costs are step one
Once you know what it costs, here's how the rest of the project goes: what order, what a fair quote looks like, and how people actually pay for it.
What order to do it in
Envelope first, equipment second: how to sequence a retrofit to your budget and your rebates' deadlines.
How to read a quote
What belongs on a insulation quote, and the red flags that mean keep shopping.
How to pay for insulation
Why this is the most subsidized work in home energy, and what pays for the part rebates miss.
State energy loans
The state and utility loan programs we have verified at the administrator, with rates and conditions.