Home insulation types break down along two axes at once: the form the product takes (batts and rolls, blown-in loose-fill, spray foam, rigid foam board, or radiant barrier) and the material it is made from (fiberglass, mineral wool, cellulose, or polymer foam). Getting both right matters because a material like cellulose can arrive as loose-fill or dense-pack, and the same job can be done by two very different forms. This guide maps every type by form and material, gives the R-value per inch, shows where each belongs in the house, and lists typical 2026 installed cost.
What are the main types of home insulation?
There are four basic forms of home insulation: batts and rolls, blown-in loose-fill, spray foam, and rigid foam board, plus radiant barrier as a fifth reflective category. Each form can be made from more than one material. Fiberglass shows up as batts, loose-fill, and board; cellulose is almost always loose-fill or dense-pack; foam comes as spray or rigid board. The form controls how it installs and where it fits; the material controls R-value per inch, fire behavior, and moisture response.
| Form | Common materials | R-value per inch | Where it fits best |
|---|---|---|---|
| Batts and rolls | Fiberglass, mineral wool | R-3.0 to R-3.8 | Open stud and joist cavities, unfinished walls, floors, attic joists |
| Blown-in loose-fill | Cellulose, fiberglass, mineral wool | R-2.2 to R-3.8 | Attic floors, closed wall cavities, irregular framing |
| Spray foam | Open-cell and closed-cell polyurethane | R-3.5 to R-7.1 | Rim joists, cathedral ceilings, walls, air-leaky cavities |
| Rigid foam board | EPS, XPS, polyiso | R-3.8 to R-7.0 | Basement and foundation walls, exterior sheathing, slab edge, low-slope roofs |
| Radiant barrier | Reflective aluminum foil | No R-value (reflects radiant heat) | Vented attics in hot, sunny climates |
The four insulation materials, compared
Four materials cover nearly every residential job: fiberglass, mineral wool, cellulose, and spray polyurethane foam. Fiberglass is the cheapest and most common. Mineral wool (also sold as rockwool) adds fire resistance and sound control. Cellulose is recycled paper treated for fire and pests, with a better R-value per inch than blown fiberglass. Spray foam air-seals as it insulates and reaches the highest R-values, at the highest cost.
| Material | Forms available | R-value per inch | Fire and moisture notes |
|---|---|---|---|
| Fiberglass | Batts, loose-fill, rigid board | R-2.2 to R-3.8 | Noncombustible; loses R-value if compressed or wet |
| Mineral wool (rockwool) | Batts, loose-fill | R-3.0 to R-3.8 | Rated to roughly 1,800 F; sheds water, does not wick |
| Cellulose | Loose-fill, dense-pack | R-3.2 to R-3.8 | Borate-treated for fire and pests; can settle if not dense-packed |
| Spray foam | Open-cell, closed-cell | R-3.5 to R-7.1 | Closed-cell is a Class II vapor retarder; needs a thermal barrier indoors |
Insulation by form: how each type installs
Form decides installation method and which cavities a type can reach. Batts drop into open framing by hand. Loose-fill is blown through a hose so it flows around wires and pipes. Spray foam is mixed and sprayed as a liquid that expands to fill gaps. Rigid board is cut and fastened to flat surfaces. Radiant barrier is stapled or laid to face an air space.
Batts and rolls
Batts and rolls are pre-cut or continuous blankets of fiberglass or mineral wool sized to fit standard 16-inch and 24-inch framing. They deliver about R-3.0 to R-3.8 per inch and are the most DIY-friendly form because they need no machine. The weak point is fit: any gap, compression, or item stuffed behind wiring cuts real-world R-value. Batts suit open walls, floors over unconditioned space, and accessible attic joists.
Blown-in loose-fill
Blown-in insulation is loose particles of cellulose, fiberglass, or mineral wool blown into place with a machine. It flows around obstructions that batts cannot follow, which makes it the standard choice for attic floors and for filling closed wall cavities through small drilled holes. Cellulose runs R-3.2 to R-3.8 per inch, blown fiberglass R-2.2 to R-2.7. Loose-fill can settle over time unless it is dense-packed in walls.
Spray foam: open-cell vs closed-cell
Spray foam is a two-part liquid that expands on contact and cures to a solid. Open-cell foam is lighter, stays flexible, and gives about R-3.5 to R-3.9 per inch. Closed-cell foam is denser, adds structural rigidity, blocks vapor, and reaches R-4.9 to R-7.1 per inch, the highest of any common home type. Both air-seal as they insulate, which is why foam is used at rim joists, cathedral ceilings, and leaky cavities.
Rigid foam board
Rigid foam board is cut panels of expanded polystyrene (EPS), extruded polystyrene (XPS), or polyisocyanurate (polyiso). EPS runs about R-3.8 to R-4.2 per inch, XPS about R-4.2 to R-5.2, and polyiso the highest at roughly R-6.8 to R-7.0. Board is fastened to flat surfaces: basement and foundation walls, exterior sheathing for continuous insulation, slab edges, and low-slope roof decks. It resists moisture better than fibrous batts.
Radiant barrier and reflective insulation
A radiant barrier is a reflective aluminum foil that blocks radiant heat rather than slowing conductive heat, so it carries no meaningful R-value on its own. It works only when it faces an open air space, typically stapled to attic rafters in hot, sunny climates where it can cut cooling load. In cold climates it does little, and it never replaces conventional R-value insulation on the attic floor.
Which insulation type goes where in a home?
The right type depends on the location, not just the material. Attics take deep loose-fill or batts to hit high R-values cheaply. Walls take batts in new construction or dense-pack in existing cavities. Foundations and rim joists favor foam because it handles moisture and air leakage. This location map is what most type guides skip, and it is where choosing by form pays off.
| Location | Best-fit types | Typical target R-value (2021 IECC) |
|---|---|---|
| Attic floor | Blown-in cellulose or fiberglass, batts | R-49 to R-60 |
| Cathedral or vaulted ceiling | Closed-cell spray foam, rigid board | R-38 to R-49 |
| Exterior walls (new) | Fiberglass or mineral wool batts, plus exterior rigid board | R-13 to R-21 cavity |
| Existing closed walls | Dense-pack cellulose, injection foam | R-13 to R-15 |
| Floors over unconditioned space | Batts, closed-cell spray foam | R-19 to R-30 |
| Rim or band joist | Closed-cell spray foam, rigid board with sealant | R-15 to R-21 |
| Basement and foundation walls | Rigid foam board, closed-cell spray foam | R-10 to R-15 |
| Crawlspace walls (sealed) | Rigid board, closed-cell spray foam | R-10 to R-19 |
How much does each insulation type cost in 2026?
Installed cost tracks the form and depth more than the brand. Fiberglass batts are the cheapest per square foot; closed-cell spray foam is the most expensive because it is priced by board foot and needs licensed applicators. The figures below are typical 2026 installed ranges and can vary widely by region, access, and the R-value target, so treat them as planning numbers rather than quotes.
| Type | Typical 2026 installed cost | DIY-friendly? |
|---|---|---|
| Fiberglass batts | $0.80 to $2.40 per sq ft | Yes |
| Blown-in cellulose or fiberglass | $1.00 to $2.80 per sq ft | Rental blower, moderate |
| Open-cell spray foam | $0.45 to $0.75 per board foot | No, pro applied |
| Closed-cell spray foam | $1.00 to $1.50 per board foot | No, pro applied |
| Rigid foam board | $0.75 to $2.00 per sq ft | Yes |
| Radiant barrier | $0.15 to $0.50 per sq ft | Yes |
Which insulation type is best for your home?
No single type wins everywhere. Match the type to the job using three questions: is the cavity open or closed, does the spot see moisture or air leakage, and what R-value does the location need. Fiberglass or cellulose covers most attics and open walls at the lowest cost. Foam earns its price where air-sealing and moisture matter.
- Open framing you can reach: use batts or blown-in fiberglass or cellulose for the best cost per R-value.
- Closed existing walls: use dense-pack cellulose or injection foam through small drilled holes.
- Wet or air-leaky spots (rim joists, crawlspaces, foundations): use closed-cell spray foam or rigid board.
- Fire or sound priority: use mineral wool batts.
- Hot-climate attic with a radiant heat problem: add a radiant barrier on top of, not instead of, floor insulation.
Whatever type you pick, air-sealing first and hitting the right R-value for your climate zone matter more than the material label. Compare exact depths on our insulation R-value chart, check which materials pack the most R per inch in our guide to the highest R-value insulation, and see the location-specific picks for attic insulation. For form deep-dives, read our breakdowns of blown-in insulation and open-cell vs closed-cell spray foam.
Frequently asked questions
What are the four main types of home insulation?
The four basic forms are batts and rolls, blown-in loose-fill, spray foam, and rigid foam board. A fifth reflective category, radiant barrier, blocks radiant heat instead of adding R-value. By material, the four common choices are fiberglass, mineral wool, cellulose, and spray polyurethane foam. Most homes combine two or three types, matched to the attic, walls, and foundation.
Which type of home insulation has the highest R-value?
Closed-cell spray foam has the highest R-value of any common home insulation, at roughly R-4.9 to R-7.1 per inch. Polyisocyanurate (polyiso) rigid board is close behind at about R-6.8 to R-7.0 per inch. Fiberglass batts and cellulose sit near R-3.0 to R-3.8 per inch, so they need more thickness to reach the same total R-value.
What insulation type is best for walls?
For open walls in new construction, fiberglass or mineral wool batts sized to the stud cavity are the standard, often paired with exterior rigid foam board for continuous insulation. For existing closed walls, dense-pack cellulose or injection foam blown through small drilled holes fills the cavity without tearing out drywall. Both approaches target roughly R-13 to R-21 depending on climate zone.
Do radiant barriers have an R-value?
Radiant barriers carry no meaningful R-value because they reflect radiant heat rather than slowing conductive heat flow. Their benefit shows up only when the foil faces an open air space, such as an attic under a hot roof. They can cut summer cooling load in sunny climates but do little in cold climates and never replace R-value insulation on the attic floor.
What is the difference between batt and blown-in insulation?
Batts are pre-cut blankets of fiberglass or mineral wool installed by hand into open framing. Blown-in insulation is loose cellulose or fiberglass particles blown through a hose so they flow around wires, pipes, and irregular framing. Batts are cheaper and DIY-friendly in accessible cavities; blown-in gives better coverage in attics and closed walls where a continuous blanket cannot be fitted.
How much does home insulation cost in 2026?
Typical 2026 installed costs run about $0.80 to $2.40 per square foot for fiberglass batts, $1.00 to $2.80 for blown-in cellulose or fiberglass, and $0.75 to $2.00 for rigid foam board. Spray foam is priced by board foot, roughly $0.45 to $0.75 open-cell and $1.00 to $1.50 closed-cell. Actual pricing varies by region, access, and R-value target.
Reviewed by The Roofing Brief Team. Last reviewed July 2026.