Comparison of Insulation Types

There is no single best insulation for every home. The right choice depends on where the insulation is being installed, your climate zone, your budget, air leakage issues, moisture exposure, and your overall energy-efficiency goals.

This guide compares the five main insulation types homeowners commonly consider:

• Fiberglass insulation
• Spray foam insulation
• Cellulose insulation
• Foam board insulation
• Mineral wool insulation

The goal is to help you quickly understand the strengths, drawbacks, costs, and ideal use cases for each insulation type so you can make a more informed decision for your home.

When comparing insulation, it is important to remember that R-value is only part of the equation. Installation quality, air sealing, moisture management, and proper ventilation also play major roles in overall performance.

What Matters Most When Comparing Insulation

The best way to compare insulation is to focus on a few core factors:

• Where the insulation is going
• Your climate zone
• Target R-value
• Air leakage issues
• Moisture exposure
• Available installation depth
• Budget

For example, a large open attic may benefit from blown-in fiberglass or cellulose, while a basement wall may be a better fit for foam board insulation.

Homes with significant air leakage may benefit more from spray foam in targeted areas, while homeowners focused on sound control may lean toward mineral wool.

Quick Comparison Chart

Home Insulation Type Comparison

Insulation Type	Common Forms	Best For	Main Advantage	Main Drawback	Typical Cost Range
Fiberglass	Batts, rolls, blown-in	Attics, walls	Affordable and widely available	Does not air seal	Low
Spray Foam	Open-cell, closed-cell	Air sealing, rim joists, rooflines	Excellent air sealing	Higher cost	High
Cellulose	Loose-fill, dense-pack	Attics, retrofit walls	Dense coverage	Moisture management matters	Low to Mid
Foam Board	EPS, XPS, Polyiso	Basements, exterior walls	High R-value per inch	Requires careful detailing	Mid
Mineral Wool	Batts, boards	Sound control, fire resistance	Dense and durable	Higher cost than fiberglass	Mid to High

Fiberglass Insulation

Fiberglass insulation is one of the most commonly used insulation materials in homes. It is available in batts, rolls, and blown-in forms and is often used in attics, walls, and floor systems.

Homeowners often choose fiberglass because it is affordable, easy to source, and suitable for many standard framing situations.

However, fiberglass insulation does not create an air seal by itself, which means gaps and air leakage can still reduce overall efficiency if air sealing is not addressed first.

Best Uses for Fiberglass

• Open attic floors
• Standard wall framing
• Budget-focused projects
• DIY-friendly applications

Spray Foam Insulation

Spray foam insulation expands during installation to fill gaps and cracks, helping reduce both heat transfer and uncontrolled air leakage.

There are two main types:

• Open-cell spray foam
• Closed-cell spray foam

Closed-cell spray foam typically provides a higher R-value per inch and greater moisture resistance, while open-cell foam is softer and often used for interior applications.

Spray foam insulation is commonly used in:

• Rim joists
• Rooflines
• Crawl spaces
• Hard-to-seal areas

Because installation requires specialized equipment and safety procedures, professional installation is usually recommended.

Cellulose Insulation

Cellulose insulation is primarily made from recycled paper fibers treated for fire resistance. It is commonly installed as loose-fill attic insulation or dense-packed wall insulation.

Because cellulose conforms well around framing and irregular spaces, it is often used in retrofit projects and attic upgrades.

Many homeowners also choose cellulose because of its recycled content and sound dampening benefits.

Common Applications

• Existing walls
• Attic upgrades
• Older homes
• Sound control projects

Foam Board Insulation

Foam board insulation, also called rigid foam insulation, comes in rigid panels and is commonly used on flat surfaces such as basement walls, exterior sheathing, and foundation walls.

The three most common foam board types are:

• EPS (Expanded Polystyrene)
• XPS (Extruded Polystyrene)
• Polyiso (Polyisocyanurate)

Foam board insulation is valued for its high R-value per inch and ability to provide continuous insulation across framing.

Common Applications

• Basement walls
• Exterior wall sheathing
• Garage doors
• Crawl space walls
• Attic hatches

Common Foam Board Types

Foam Board Type	Approximate R-Value Per Inch	Common Uses
EPS	Around R-3.6 to R-4.2	General insulation applications
XPS	Around R-5	Foundations and below-grade use
Polyiso	Around R-6 to R-6.5	Exterior walls and roof systems

Mineral Wool Insulation

Mineral wool insulation, sometimes called stone wool or rock wool insulation, is known for its fire resistance, sound dampening, and dense fiber structure.

Mineral wool insulation is commonly installed in wall cavities, floors, ceilings, garages, and areas where sound control is important.

Compared to fiberglass, mineral wool batts are denser and often fit more tightly within framing cavities.

Key Benefits

• Excellent sound dampening
• Fire-resistant properties
• Moisture resistance
• Durable dense batt structure

Best Insulation by Area of the Home

Best Insulation Types by Location

Area of Home	Common Insulation Choices	Why They Work Well
Attic floors	Fiberglass or cellulose	Cost-effective for large open areas
Existing walls	Cellulose or spray foam	Works well in enclosed cavities
Exterior walls	Fiberglass or mineral wool	Standard cavity insulation solutions
Basement walls	Foam board or spray foam	Better moisture resistance
Rim joists	Spray foam	Excellent air sealing
Sound-control walls	Mineral wool	Strong sound dampening

Best Insulation by Homeowner Priority

Lowest Upfront Cost

Fiberglass insulation is often the most affordable starting point for many homes.

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Best Air Sealing

Spray foam insulation is usually the strongest option for reducing uncontrolled air leakage.

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Best Sound Control

Mineral wool insulation is commonly preferred for reducing sound transfer between rooms.

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Best for Retrofit Walls

Cellulose insulation is often used in enclosed wall retrofit projects because it can be dense-packed into existing cavities.

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Best for Basement Walls

Foam board insulation is commonly used on basement and foundation walls because it performs well on flat masonry surfaces.

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Cost Comparison

The cost of insulation depends on:

• Material type
• Installation method
• Accessibility
• Home size
• Climate zone
• Existing insulation conditions

General Insulation Cost Positioning

Insulation Type	General Cost Position
Fiberglass	Low
Cellulose	Low to Mid
Foam Board	Mid
Mineral Wool	Mid to High
Spray Foam	High

Any insulation material can perform poorly if it is installed incorrectly or combined with uncontrolled air leakage.

How to Choose the Right Insulation

Start by identifying the actual problem you are trying to solve.

Questions to ask include:

• Is the home drafty?
• Are energy bills unusually high?
• Are certain rooms uncomfortable?
• Is outside noise a concern?
• Is moisture present?
• Is the project a new build or retrofit?

Next, consider where the insulation is being installed and compare the strengths of each insulation type for that area.

In many homes, the best overall insulation strategy uses multiple insulation types together rather than relying on a single material everywhere.

Frequently Asked Questions