Types of Home Insulation

Home insulation comes in several materials and forms, and those two ideas are often confused. Fiberglass, cellulose, spray foam, foam board, and mineral wool are material families. Batts, rolls, loose-fill, sprayed foam, and rigid boards describe how insulation is made or installed.

Choosing between them is less about finding one universal “best” product and more about matching the material and form to the part of the home, the target R-value, air leakage, moisture conditions, available space, and installation method.

This guide explains the main options, where each is commonly used, and what to evaluate before deciding. For a deeper side-by-side review, see our comparison of insulation types.

Insulation Materials vs. Insulation Forms

Homeowners often hear terms such as “fiberglass insulation” and “batt insulation” used as though they belong to the same category. They do not. Fiberglass is a material, while a batt is a pre-cut form of insulation. Fiberglass can also be installed as loose-fill, and other materials can be made into batts or boards.

Understanding this distinction makes product comparisons much easier. Start by identifying the part of the home and the type of assembly, then compare the materials and forms that can work there.

Batts and rolls: Pre-cut batts and continuous rolls fit between framing members. Fiberglass and mineral wool are common examples. They are generally best suited to open, accessible cavities with regular spacing.

Loose-fill or blown-in insulation: Small fibers or particles are blown into place. Cellulose, fiberglass, and mineral wool can be installed this way. Loose-fill is commonly used on attic floors and in enclosed or irregular cavities.

Sprayed or foamed-in-place insulation: Liquid components are applied at the jobsite and expand or cure in place. These products can insulate and reduce air leakage, but application and occupancy requirements are product-specific.

Rigid boards: Factory-made panels are installed over flat surfaces or cut to fit specific areas. Common products include expanded polystyrene, extruded polystyrene, polyisocyanurate, and rigid mineral wool.

Reflective insulation and radiant barriers: These systems reduce radiant heat transfer across an adjacent air space. They work differently from bulk insulation and are most often considered in certain attic or roof applications, especially in warm, sunny climates.

The Main Types of Home Insulation

The five material families below cover most residential insulation projects. Each has useful applications, but each also has limitations that should be considered before choosing a product.

Fiberglass Insulation

Fiberglass is made from fine glass fibers and is commonly sold as batts, rolls, and loose-fill. It is widely used in attic floors, framed walls, ceilings, and floors because it is available in many sizes and R-values.

Its main advantages are availability, product variety, and suitability for many open-cavity projects. The main limitation is that fiberglass does not create an air barrier by itself. Gaps, compression, wind washing, and poor cuts around wires or electrical boxes can reduce installed performance.

Learn more about fiberglass insulation, including common forms, applications, advantages, and limitations.

Cellulose Insulation

Cellulose is a fiber insulation made primarily from recycled paper products and treated for fire resistance. It is most often installed as loose-fill on attic floors or as dense-pack insulation in enclosed wall and floor cavities.

Because it is blown into place, cellulose can conform around framing and irregular spaces better than a poorly fitted batt. Its performance depends on installed depth or density, and existing roof leaks, plumbing leaks, or other moisture problems should be corrected before installation. Professional equipment and dust control are often needed.

Explore how cellulose insulation for homes is used in attics, walls, and retrofit projects.

Spray Foam Insulation

Spray polyurethane foam is mixed and applied at the jobsite, where it expands or cures into place. Open-cell and closed-cell spray foams differ in density, R-value, vapor permeability, water response, and appropriate applications.

Spray foam can provide insulation and air sealing in one application, which may be useful at rim joists, complex rooflines, and other hard-to-seal locations. It also requires careful product selection, trained installation, and an assembly design that manages moisture correctly. Safe work practices and re-entry timing must follow the manufacturer and installer guidance for the specific product and conditions.

Read the full guide to spray foam insulation before comparing open-cell and closed-cell options.

Foam Board Insulation

Foam board insulation consists of rigid panels, most commonly made from expanded polystyrene, extruded polystyrene, or polyisocyanurate. Boards can be installed on foundation walls, basement walls, roofs, floors, and exterior wall surfaces, depending on the product and assembly.

A continuous board layer can reduce heat flow through framing members, a problem known as thermal bridging. However, the seams, edges, fasteners, and penetrations still need proper detailing. Different foam boards also have different vapor, temperature, water-absorption, and fire-protection requirements, so products should not be treated as interchangeable.

Learn where foam board insulation may fit into foundation, wall, roof, and retrofit projects.

Mineral Wool Insulation

Mineral wool is made from spun rock or slag fibers and is commonly sold as semi-rigid batts or rigid boards. It is used in framed walls, floors, ceilings, exterior wall systems, and assemblies where fire resistance or sound absorption is an important goal.

Mineral wool products are generally denser and more rigid than standard fiberglass batts, which can help them hold their shape and fit around some obstructions. They do not air seal on their own, and they may cost more or be less widely stocked than fiberglass in some areas. Exact properties vary by product.

Compare applications and tradeoffs in our guide to mineral wool insulation.

Reflective Insulation and Radiant Barriers

Reflective insulation and radiant barriers deserve separate treatment because they do not work like fiberglass, cellulose, foam, or mineral wool. A reflective surface reduces radiant heat transfer when it faces an air space. Its value depends on the climate, roof or attic design, installation details, and whether dust can collect on the reflective surface.

These systems may be useful in selected attic or roof applications, particularly in hot, sunny climates, but they are usually evaluated as part of the overall assembly rather than as a direct substitute for the full amount of bulk insulation a home needs.

Home Insulation Types at a Glance

This table summarizes the most common material families without assigning a universal winner. The appropriate choice still depends on the exact product, location, climate, and condition of the home.

Home Insulation Types at a Glance

Material	Common Forms	Common Applications	Main Strength	Important Limitation
Fiberglass	Batts, rolls, loose-fill	Attic floors, open walls, ceilings, floors	Widely available and adaptable	Needs careful fitting and separate air sealing
Cellulose	Loose-fill, dense-pack	Attic floors, enclosed walls and floors	Conforms well to irregular and retrofit cavities	Installed depth or density and moisture conditions matter
Spray foam	Open-cell and closed-cell foam	Rim joists, rooflines, irregular cavities, targeted air sealing	Can insulate and reduce air leakage	Professional application, product safety, cost, and moisture design
Foam board	Rigid EPS, XPS, and polyisocyanurate panels	Foundations, basements, roofs, exterior continuous insulation	Can create a continuous insulation layer	Seams, penetrations, vapor behavior, and fire protection require detailing
Mineral wool	Batts and rigid boards	Walls, floors, ceilings, exterior systems	Dense fit, fire resistance, and sound absorption	Usually does not air seal and may cost more

Choosing Insulation by Area of the Home

The same material can be a sensible choice in one part of a house and a poor fit in another. Start with the location and the way that part of the building is intended to control heat, air, and moisture.

Attics and Rooflines

In a traditional vented attic, the main air and thermal boundary is usually at the attic floor. Loose-fill fiberglass or cellulose can cover irregular framing and existing insulation, while batts may work in open, regularly spaced cavities when they are cut and fitted carefully. Air leaks at plumbing, wiring, chases, top plates, and attic hatches should generally be addressed before adding insulation.

An unvented attic or insulated roofline is a different assembly. Spray foam or rigid insulation may be part of the design, but roof moisture, ventilation strategy, combustion safety, and local code requirements need to be considered. Insulation should not block required soffit ventilation in a vented attic.

See the full attic insulation guide for a location-specific overview.

Exterior Walls

When wall cavities are open during construction or remodeling, fiberglass, mineral wool, cellulose, spray foam, and some combinations may all be possible. The best fit depends on cavity depth, framing, exterior layers, vapor control, budget, and whether continuous insulation will be added outside the framing.

For finished walls, dense-pack cellulose or blown fiberglass may be installed through access holes when the cavities and wall condition are suitable. Removing siding or interior finishes creates more options, including continuous foam board or mineral wool on the exterior. Existing moisture or bulk-water problems should be corrected first.

Learn more about choosing materials for wall insulation.

Basements and Crawl Spaces

Below-grade spaces require moisture planning before insulation. Drainage, water entry, humidity, ground moisture, pests, and the intended ventilation or conditioning strategy all affect the right approach.

Rigid foam board and closed-cell spray foam are often considered for concrete or masonry surfaces because they can provide insulation while limiting contact between indoor air and cold foundation surfaces. Fibrous insulation may be appropriate in some dry framed assemblies or floors, but it should not be used to hide an active moisture problem. Fire protection and termite-inspection requirements may also affect the assembly.

Review the options in our crawl space insulation guide.

Floors, Rim Joists, and Band Joists

Floors over garages, unconditioned spaces, or vented crawl spaces may use fiberglass or mineral wool batts when cavities are dry, accessible, and properly supported. The insulation should remain in contact with the air boundary rather than sagging away from the subfloor.

Rim and band joists often include small cracks and many material transitions. Rigid foam cut to fit and sealed at the edges, or professionally installed closed-cell spray foam, can provide both insulation and air sealing. Fibrous insulation alone generally does not seal these leakage paths.

Interior Walls and Ceilings

Interior partitions usually do not need thermal insulation unless they separate spaces with different temperature or humidity conditions. Fiberglass and mineral wool may still be used to improve sound absorption between rooms, but sound control depends on the entire wall or ceiling assembly, including air sealing, framing, resilient connections, and finish layers.

What to Consider Before Choosing Insulation

An insulation product can perform well only when it is appropriate for the assembly and installed correctly. Use the following questions to narrow the options before comparing brands or prices.

1. What Part of the Home Are You Insulating?

Determine whether the project involves an attic floor, roofline, wall cavity, exterior wall, basement wall, crawl space, floor, rim joist, or another assembly. Access, framing, exposure, and drying potential differ from one location to another.

2. What R-Value Is Needed?

R-value measures resistance to heat flow. The appropriate level depends on climate, the part of the home, local code, available space, and any insulation already present. Compare the total labeled R-value at the intended thickness rather than assuming every product in a material category performs the same.

Use our homeowner guide to understanding R-value as a starting point.

3. Where Is Air Leaking?

Insulation slows heat transfer, but most insulation materials do not stop moving air. Drafts and bypasses around attic penetrations, rim joists, kneewalls, recessed fixtures, and wall transitions may need a separate air-sealing plan. Spray foam can perform both functions in some applications, but the entire air barrier still needs continuity.

4. Are There Moisture or Water Problems?

Do not cover roof leaks, plumbing leaks, foundation seepage, high crawl-space humidity, or condensation with new insulation. The assembly should be able to manage rain, ground moisture, indoor humidity, and drying. Product vapor permeability is one factor, but it is not a substitute for a complete moisture strategy.

5. How Much Space Is Available?

Some cavities have enough depth for lower-R-value-per-inch materials, while others are constrained by framing or clearances. A higher R-value per inch may help in tight spaces, but continuous insulation and thermal-bridge control can sometimes improve the whole assembly more effectively than simply filling the cavity with a higher-rated product.

6. Can the Product Be Installed Well?

A theoretically strong product can underperform when it is compressed, gapped, under-filled, poorly bonded, or disconnected from the air barrier. Consider cavity shape, obstructions, access, equipment, installer training, and the ability to inspect the completed work.

7. What Does the Full Project Cost Include?

Material price alone does not show the full cost. Compare bids or project plans using the same target R-value, area, preparation, air sealing, removal, disposal, protective coverings, access work, and finish repairs. The least expensive material may not be the least expensive completed assembly, and a premium material is not automatically the better value.

8. Are Fire, Sound, or Environmental Priorities Important?

Some homeowners prioritize noncombustible materials, sound absorption, recycled content, low embodied carbon, or reduced use of petrochemical products. These goals can help narrow the choices, but they should be weighed alongside moisture behavior, installation quality, durability, and the needs of the building assembly.

The Federal Trade Commission requires most home insulation sold to consumers to disclose its R-value. Compare the labeled R-value at the intended thickness and review the product fact sheet rather than relying only on a generic R-value-per-inch chart.

Why Material Choice Is Only Part of Performance

Insulation is one part of the home enclosure. Good performance depends on how the insulation works with the air barrier, drainage layers, vapor control, ventilation, framing, and mechanical systems.

It is also normal for one home to use several insulation types. A project might combine loose-fill insulation on an attic floor, rigid foam at a foundation wall, mineral wool in a sound-sensitive partition, and sealed rigid foam or spray foam at rim joists. The question is not whether one material wins everywhere, but whether each assembly has a continuous strategy for heat, air, and moisture.

Related improvements such as air sealing, ventilation corrections, and moisture work should be evaluated as part of the same plan. Explore insulation add-ons and enhancements for more context.

DIY vs. Professional Installation

Some insulation work is manageable for experienced homeowners, while other projects require specialized equipment, training, protective measures, or building-science judgment. The form of insulation and the condition of the work area are often more important than the material name when deciding who should install it.

Typical Installation Complexity by Project

Project or Form	Typical Complexity	Why
Batts or rolls in open, dry, regular cavities	Basic to intermediate	Requires accurate cutting, full contact, safe access, and separate air sealing
Loose-fill attic insulation	Intermediate	Requires blowing equipment, depth control, ventilation protection, and air sealing first
Rigid board on accessible flat surfaces	Intermediate	Requires cutting, fastening, seam and edge sealing, and code-compliant protection
Enclosed-wall or dense-pack retrofit	Professional is often appropriate	Requires equipment, density control, cavity checks, and finish access
Spray foam installation	Advanced professional work	Requires trained application, ventilation, protective equipment, and product-specific occupancy planning
Complex roofline, moisture, or foundation project	Professional assessment is often appropriate	Assembly design and water, vapor, combustion, or code issues can affect safety and durability

Do-it-yourself work is most reasonable when the area is dry, accessible, structurally sound, free of suspected hazardous materials, and simple enough to inspect. Professional help is usually the safer choice for spray foam, enclosed cavities, complex roof assemblies, persistent moisture, major air leakage, hard-to-reach areas, or work near combustion equipment and significant electrical hazards.

Older attics may contain vermiculite insulation that could be contaminated with asbestos. Do not disturb suspected vermiculite until it has been appropriately evaluated. For spray foam, ask the installer for the exact product information, ventilation plan, work-area isolation steps, and product-specific guidance for vacating and re-entering the home.

Learn More

Compare DIY vs. professional insulation and review what to consider when hiring an insulation professional.

Frequently Asked Questions