A 1,500 square foot attic in Waukegan costs about $1,500 to $3,000 to insulate with blown fiberglass to R-49, with a likely cost near $2,250. Cellulose on the same attic runs about $1,800 to $3,600, and mineral wool about $2,250 to $4,500. Those are installed ranges, not single prices: access, slope, hose runs, and the existing insulation all move the number. This guide breaks the cost down by attic size and material, explains what the installed range includes and what it leaves out, and shows how to compare quotes.
Cost Per Square Foot
The installed cost per square foot is the cleanest way to compare quotes, because it strips out the attic size. Blown fiberglass runs $1.00 to $2.00 per square foot installed to R-49. Cellulose runs $1.20 to $2.40 per square foot. Mineral wool runs $1.50 to $3.00 per square foot. The material alone is a smaller piece of the total than most homeowners expect: on a 1,500 square foot attic, 40 bags of fiberglass cost $1,400 to $2,000, while the installed total is $1,500 to $3,000, so labor, equipment, and prep are roughly a third of the job. For cellulose the material is far cheaper, $550 to $800 for 50 bags, and labor is the bigger share. That is why the installed ranges for fiberglass and cellulose overlap even though their bag prices are far apart.
The per-square-foot range is the same whether the attic is 1,000 or 2,000 square feet, but the total moves with the area, and the low end of the range is for easy attics. A wide-open attic with a big hatch and a short hose run is at $1.00 per square foot for fiberglass, while a low-slope attic with a small scuttle hole and a long hose run is at $2.00. Most Waukegan attics land in the middle, which is why the likely midpoint is the most useful number for budgeting. Use the blown-in insulation calculator to get the range and the midpoint for your exact attic size and material.
Cost by Attic Size
| Attic size | Fiberglass installed (R-49) | Cellulose installed (R-49) | Mineral wool installed (R-49) |
|---|---|---|---|
| 1,000 sq ft | $1,000 to $2,000 (likely $1,500) | $1,200 to $2,400 (likely $1,800) | $1,500 to $3,000 (likely $2,250) |
| 1,500 sq ft | $1,500 to $3,000 (likely $2,250) | $1,800 to $3,600 (likely $2,700) | $2,250 to $4,500 (likely $3,375) |
| 2,000 sq ft | $2,000 to $4,000 (likely $3,000) | $2,400 to $4,800 (likely $3,600) | $3,000 to $6,000 (likely $4,500) |
Those totals are for an attic with no insulation in place, taken to R-49. If your attic already has insulation, the total falls, because the crew adds only what is missing. A 1,200 square foot attic with 6 inches of old fiberglass needs a cellulose top-up of 28 bags, and the installed range is $1,440 to $2,880, with a likely cost near $2,160. A 2,400 square foot attic with 10 inches of old cellulose needs only 21 bags of mineral wool, and the installed range is $3,600 to $7,200, with a likely cost near $5,400. The material cost falls with the bag count, but the installed range per square foot stays the same, because the crew still has to set up, run the hose, and check the depth.
What the Installed Range Includes
The installed range covers the material, the labor to blow it, the machine and hose setup, the baffles at the eaves that keep the soffit vents open, and a depth check at the end. It does not cover air sealing, and that is the most important gap to understand. Air sealing means caulking and foaming the gaps around pipes, wires, recessed lights, and the attic hatch before the insulation goes in. It usually costs a few hundred dollars, and it is worth more than the insulation itself on a leaky attic, because insulation does not stop air. A quote that includes air sealing is worth more than a cheaper quote that skips it.
Removing old insulation is also separate, and it is only needed if the old layer is wet, moldy, or damaged. A dry, undamaged old layer stays in place and the new material goes over it. Repairing a roof leak is separate too, and it must happen first, because wet insulation is worse than thin insulation. Adding a raised hatch, walkway boards, or ventilation work is separate as well. A good quote lists each item on its own line, so you can see the insulation price, the air sealing price, and anything else, instead of one lump sum that hides what you are paying for.
What Moves the Price
Access is the biggest price driver after the material. A large hatch or pull-down stair lets the crew and hose in easily; a small scuttle hole slows everything down and pushes the price toward the high end. Roof slope matters too: a steep-pitch attic with standing room is fast to work in, while a low-slope attic where the crew crawls on their knees is slow. The hose run matters too: the machine sits on the truck, so a long run from the driveway to the hatch costs time and material.
How to Compare Quotes
Compare quotes line by line, not by the bottom number. The first thing to check is the material and the bag count: does the quote name the material, the number of bags, and the target R-value, and does the bag count match the coverage chart? A 1,500 square foot attic to R-49 needs 40 bags of fiberglass, 50 of cellulose, or 46 of mineral wool, and a quote with far fewer bags is short-changing the attic. The second is air sealing: is it included, and which gaps will be sealed? The third is the baffles and the vent check.
Use the fairness checker in the blown-in insulation calculator to place any quote against the typical installed range for your attic. A quote below the range is not automatically a bargain: check what it leaves out. A quote inside the range is fair if it names the material, the bag count, and the target R-value in writing. A quote above the range is not automatically a rip-off: a steep attic, a small hatch, or added air sealing can justify it, but the quote should explain why in a line-by-line breakdown. Get two or three quotes, and hire the contractor whose quote you can check against the numbers here.
Related reading: blown-in insulation calculator, plus our guides on attic insulation cost and how much blown-in insulation do I need, and the roofing calculators hub.
Want a Written Quote?
Call now for a free attic inspection in Waukegan and Lake County. We measure the attic, check the ventilation, and give you a written quote with the bag count and the target R-value.
Frequently Asked Questions
How much does blown-in insulation cost for a 1,500 sq ft attic?
For a 1,500 sq ft attic in Waukegan, blown fiberglass installed to R-49 runs about $1,500 to $3,000, with a likely cost near $2,250. Cellulose on the same attic runs about $1,800 to $3,600, and mineral wool about $2,250 to $4,500. The material alone is about $1,400 to $2,000 for 40 bags of fiberglass, or $550 to $800 for 50 bags of cellulose. The final quote comes after an inspection.
What is the cheapest blown-in insulation?
Cellulose has the cheapest material: $11 to $16 per bag against $35 to $50 for fiberglass and $45 to $65 for mineral wool. But the installed cost is what matters, and cellulose installed runs $1.20 to $2.40 per sq ft against $1.00 to $2.00 for fiberglass. On a 1,500 sq ft attic the installed ranges overlap, so get a quote for both materials before you decide on price alone.
Is blown-in insulation worth the cost?
For most Waukegan homes with thin attic insulation, yes. Going from R-15 to R-49 cuts the heat loss through the attic floor by about two-thirds, and the attic floor is usually the biggest heat-loss surface in the house. The work takes a day, it does not disturb the rooms below, and the comfort change shows up on the first cold night. The exact payback depends on your heating bills, so compare the quote against a winter of heating costs, not against doing nothing.
Does the price include removing old insulation?
Usually not. The installed ranges on this page cover the new material, the labor to blow it, the baffles at the eaves, and a depth check. Removing old insulation is a separate job, and it is only needed if the old layer is wet, moldy, or damaged. Air sealing is also usually separate. A good quote lists each item on its own line so you can see what you are paying for.
Why do blown-in insulation quotes vary so much?
The attic itself is the biggest reason. A wide-open attic with a big hatch and a short hose run from the truck is at the low end of the range. A low-slope attic with tight corners, a small scuttle hole, and a long hose run is at the high end. The material matters too: mineral wool costs more per bag than cellulose. And some quotes include air sealing while others leave it out, which moves the total by a few hundred dollars. Always compare quotes line by line, not just the bottom number.
Zayn Robert is a content specialist focused on roofing, construction, and home improvement topics. He creates easy-to-understand guides that help homeowners learn about roof measurements, materials, maintenance, and repair decisions. His work combines detailed research with practical insights from roofing professionals at Zuniga Roofing Inc.