Blown-in attic insulation: keep the heat out of your rooms

What you get

You get a cooler upstairs. A deeper layer slows heat as it moves from a hot attic into the rooms you cool. South Florida cools far more than it heats, so this is the layer that matters most here.

• The result. A thicker, even layer across the attic floor, measured and photographed.
• The effort. On an open attic floor, the work stays in the attic. Nothing in your living space is torn open.
• The risk. Ask for the scope, the product and the price in writing before anything starts.
• The wait. Ask for start and finish dates in your written scope.

No one can promise a bill cut without measuring your house, so this site prints no savings figure.

What blown-in insulation is, and when it fits

Blown-in insulation is loose fill. A machine chops it up and blows it through a hose across the attic floor. The fill settles around joists, wires and pipes. Tiny pockets of trapped air slow the heat.

It fits an attic with an open floor, a dry roof and a thin layer today. It also fits an older layer that has settled and needs topping up. It is easy to add to later, and easy to take out.

It does not seal the attic. Ducts or an air handler that sit in the attic stay in the hot space. If that is your house, price spray foam next to it.

Fiberglass or cellulose

Most jobs use fiberglass or cellulose. Fiberglass is spun glass fiber. Cellulose is recycled paper treated for fire resistance.

PickHVAC lists full-depth fiberglass at 1.60-2.40 USD per sq ft¹ and cellulose at 1.90-2.75 USD per sq ft^{1 1}. Block Renovation lists blown-in overall at 1.00-3.00 USD per sq ft^{2 2}. These are national guides.

Do not pick on price alone. Ask these questions:

• What R-value will be installed, in writing? R-value is how well a layer resists heat. It differs by product and by inch of depth.
• How does the product act if the attic gets damp? South Florida attics are humid, and roofs leak.
• Who stands behind it? The maker has a product warranty. The installer has a workmanship term. They are not the same thing.

How to choose

Start with what is in your attic now. Find the type and the depth in inches.

• Thin or patchy layer, open floor, dry roof. Blown-in is usually the first thing to price.
• Some insulation that has settled. Top it up. Guides price adding depth below filling an empty attic ¹.
• Wet, stained or soiled fill. Take it out first. See attic insulation removal.
• Ducts or an air handler in the attic, or you want a sealed attic. Price spray foam too, and read spray foam vs blown-in in Florida.
• Plenty of insulation and still hot. Ask about a radiant barrier or a duct check instead. More insulation will not fix every hot room.
• You think you have vermiculite insulation. Stop. Do not disturb it. See attic insulation removal.

Florida code, permits and rebates

As of October 18, 2026

New homes in Miami-Dade, Broward and Palm Beach counties need at least R-30 in the ceiling under the 2023 Florida energy code ³. Use R-30 as a target for your attic, not as a legal demand on an older house ³. For work on an existing attic, ask your building department what applies ⁴.

A Florida law that took effect July 1, 2026 lets single-family owners skip a building permit for work under $7,500, with a written request ⁵. Whether an attic job fits is each building department's call. Ask before you hire anyone.

If FPL is your electric company, its ceiling insulation rebate is $220 per installation ⁶. It applies only when your existing attic insulation is below R-8 ⁶. The whole attic must be reachable, and you must hire an FPL-approved contractor. Check with FPL first.

The federal 25C credit ended on December 31, 2025 ⁷. Ignore any page that still lists it.

Roof vents are one of the most common ways rain gets into an attic in a storm ⁸. Ask how the job keeps soffit airflow open at the edges and how the attic hatch is sealed.

How the job goes, step by step

• Measure. The installer checks the type and depth of what is there. They look for leaks, damp spots, rodent signs, loose wiring and ducts, and they take photos.
• Fix first. Roof leaks, bad wiring and open gaps get flagged before insulation goes on. Air sealing is sometimes part of a quote, so ask.
• Mark the depth. Depth rulers go up in the attic so the finished depth can be checked and photographed.
• Blow it in. A machine sits outside. A hose runs to the attic, and the fill goes across the floor to the depth in your scope.
• Check and clean up. The installer measures the finished depth, takes photos, seals and insulates the hatch, and cleans up.
• Paperwork. You get the installed R-value and the area covered, in writing.

What changes the price

Blown-in is priced by the square foot of attic floor, so size sets the base. These move it from there:

• What is there now. Topping up a layer costs less per square foot than filling an empty attic ¹.
• Old insulation. Taking it out adds 1.00-1.50 USD per sq ft⁹.
• Air sealing and repairs. Some quotes include air sealing. Others charge extra.
• Access and material. A tight attic or a hard hatch adds labor. Fiberglass and cellulose price differently.

PickHVAC gives 1875-4125 USD¹ for a typical 1,500 square foot attic. Block Renovation gives 2000-4500 USD² for the same size, with some air sealing, and 3000-7000 USD² for 2,000 square feet.

Our arithmetic: at PickHVAC's fiberglass rate of 1.60-2.40 USD per sq ft¹, a 1,500 square foot attic comes to about 2,400 to 3,600 dollars (1,500 times 1.60 and 1,500 times 2.40).

These are national guides, not South Florida quotes. A real price needs someone to measure your attic. The cost guide shows the sources side by side.

What is in writing, and the workmanship term

Before work starts, your written scope should list:

• the square feet covered, and the product and brand
• the installed R-value and the depth in inches
• who removes old insulation, and where it goes
• whether air sealing is included
• start and finish dates
• the workmanship term: how long the installer fixes problems with the work, and what that covers

The maker's product warranty is separate. We will publish the installer's workmanship term here once an installer signs. Until then, ask every bidder to put theirs in writing.

National price ranges for blown-in attic insulation

Blown-in attic insulation in South Florida: cities

• Miami
• Boca Raton
• West Palm Beach

Questions people ask