Cellulose Insulation vs Spray Foam: Which is Best?

Choosing the right insulation for your home is crucial to ensure energy efficiency and comfort. With many options like spray foam, cellulose, fiberglass, and more, it can be overwhelming to decide what’s best.

In this article, we’ll compare cellulose insulation vs spray foam – two of the most popular types of insulation. We’ll look at the pros and cons of each, including cost, effectiveness, air sealing abilities, and fire safety.

We’ll examine key factors like R-value per inch, noise reduction, and ease of installation. By understanding the performance data and ideal uses for cellulose and spray foam insulation, you’ll be equipped to make the smart choice for your insulation project, whether it’s insulating an attic, walls, or other areas.

With the right information, you can confidently choose the insulation type that aligns with your budget, project scope, and goals for energy efficiency and comfort.

What is the main difference between cellulose insulation and spray foam?

Cellulose insulation and spray foam are two of the most popular types of home insulation. Both materials have their own unique advantages and disadvantages, so the best choice for you will depend on your specific needs and budget.

Here is a table summarizing the main differences between cellulose insulation and spray foam:

FeatureCellulose InsulationSpray Foam Insulation
R-value3.7 to 4.3 per inch3.7 to 6.7 per inch
CostLess expensiveMore expensive
InstallationCan be blown into place or batts can be installedRequires specialized equipment and expertise
Environmental impactMore environmentally friendlyLess environmentally friendly
Moisture resistanceNot as moisture resistant as spray foamMore moisture resistant than cellulose insulation
SoundproofingNot as good as spray foamGood soundproofing properties

The main difference between cellulose insulation and spray foam is their R-value. R-value is a measure of how well an insulation material resists heat flow. A higher R-value means that the material is more effective at insulating. Spray foam has a higher R-value than cellulose insulation, so it can provide better insulation performance.

Another key difference is the cost of installation. Cellulose insulation is less expensive to install than spray foam. This is because cellulose insulation can be blown into place, while spray foam requires specialized equipment and expertise.

cellulose insulation is more environmentally friendly than spray foam. Cellulose insulation is made from recycled materials, while spray foam is made from petroleum products.

So, which type of insulation is right for you? The best way to decide is to consider your specific needs and budget. If you are looking for the most effective insulation, then spray foam is the better choice. However, if you are on a budget or are concerned about the environmental impact of your insulation, then cellulose insulation is a good option.

Pros and Cons of Cellulose Insulation

Understanding Cellulose Insulation

When it comes to insulating your home, cellulose insulation is a popular choice due to its affordability and eco-friendly composition.

The main difference between cellulose and other insulation materials is that it is made from recycled paper products, like newspapers, cardboard, and phone books.

This recycled material gives cellulose some advantages, but it also has some drawbacks compared to other insulations. Below we’ll look at the key pros and cons of using cellulose insulation.

Pros of Cellulose Insulation

Cellulose is appealing to many homeowners because of these beneficial factors:

  • Renewable and sustainable. Cellulose contains a high percentage of recycled paper waste, giving it eco-friendly credentials. This keeps paper products out of landfills.
  • Cost-effective. Cellulose insulation costs about the same per square foot as fiberglass batts when professionally installed. Cellulose can also be installed DIY to save on labour.
  • Good insulation value. With an R-value of around R-3.7 per inch, cellulose provides decent thermal resistance to slow heat transfer and save on energy bills.
  • Conforms to spaces. When blown in using special equipment, cellulose can conform around electric boxes, wires, and other obstructions in wall cavities.
  • Limits air infiltration. The loose fill form fills gaps and cracks that allow drafts. This improves air sealing for better energy efficiency.
  • Treated for fire safety. Cellulose is mixed with fire retardant chemicals like boric acid to meet building code safety standards.

Cons of Cellulose Insulation:

However, some downsides to consider include:

  • Settling over time. Loose-fill cellulose settles and compresses in wall cavities over several years, decreasing the R-value. Attics may need topping up.
  • Not ideal for irregular spaces. Cellulose performs best in standard stud bays. It can be tricky to achieve uniform insulation coverage in curved or oddly shaped areas.
  • Lower R-value than spray foam per inch. While cellulose insulates decently, closed-cell spray foam provides a higher R-value in less thickness.
  • Special equipment needed. Proper dense pack installation into walls requires renting or purchasing expensive blowing machines. Not a DIY-friendly job.
  • Potential for dust and mold. If cellulose is improperly installed or becomes exposed, it can allow moisture intrusion and air gaps that promote dust accumulation and mold growth.

Pros and Cons of Spray Foam Insulation

Understanding Spray Foam Insulation

Spray foam insulation is a popular choice for insulating homes and buildings thanks to its ability to insulate, air seal, and add structural rigidity. But what exactly is it and what are the pros and cons?

The main difference between spray foam and traditional insulation materials is that it starts as a liquid applied by professionals using specialized equipment. It then expands to fill cracks and voids, forming a solid foam insulation. Let’s examine the key advantages and disadvantages of spray foam.

Pros of Spray Foam Insulation

There are several beneficial factors that make spray foam worth considering:

  • Excellent air sealing. As the liquid foam expands, it seals around pipes, wires, and penetrations to prevent air leaks. This maximizes energy efficiency.
  • Higher R-value. Closed-cell spray foam provides an insulation value of around R-6 per inch, outperforming fiberglass batts. This means better thermal performance in less thickness.
  • Works for irregular spaces. The fluid foam adheres to odd-shaped cavities, curved walls, and ceilings with obstructions. Difficult for other insulations to achieve uniform coverage.
  • Provides structure. The rigid foam adds strength once cured, which is useful for framing roofs and unvented attics.
  • Minimal vapor permeability. Closed-cell foam resists moisture intrusion that could compromise insulation value.
  • Continuous insulation. Unlike batts which leave gaps between studs, spray foam insulates an entire cavity with no seams or gaps.

Cons of Spray Foam Insulation:

Limitations of Spray Foam Insulation

Some potential drawbacks to weigh include:

  • Higher cost. At $1-1.50 per square foot installed, spray foam is one of the more expensive insulation options.
  • Off-gassing concerns. Some lower-quality foams may temporarily emit VOCs during and after curing that dissipate over weeks.
  • Requires professional installation. Applying foam properly requires training and safety equipment beyond DIY abilities.
  • Messy overspray. The excess foam must be quickly cleaned before expanding and hardening on surfaces it shouldn’t.
  • Can be damaged if exposed. Rodents or penetration from screws can ruin foam’s insulation value and air sealing if left uncovered.
  • A vapour barrier may still be needed. In cold climates, a vapour barrier on the indoor side of the foam may help prevent condensation issues.

cellulose insulation vs spray foam: Comparing Two Popular Insulation Options

cellulose insulation vs spray foam: Performance and Efficiency

Installing insulation is one of the best ways to improve your home’s energy efficiency and comfort. Two of the most common types of insulation on the market are cellulose and spray foam.

Both offer effective insulation, but there are some key differences between these materials to consider when choosing which is best for your home.


An insulation’s R-value measures its ability to resist heat flow. The higher the R-value, the better it insulates.

  • Cellulose has an R-value of approximately R-3.7 per inch.
  • The R-value of spray foam is higher: open-cell is around R-3.7 per inch while closed-cell is R-6 or more per inch.

Spray foam offers a higher R-value per inch, meaning it provides better insulation performance in less thickness.

Cost Comparison

Insulation costs depend on the type, brand, contractor rates, and your location. Some typical costs per square foot installed:

  • Cellulose – $1.00 to $1.50
  • Open-cell spray foam – $1.50 to $2.00
  • Closed-cell spray foam – $2.00 to $3.00

Cellulose is the most affordable option on a cost-per-square-foot basis. Spray foam has a higher material cost due to its complex chemistry and mixing requirements. Closed-cell foam often costs up to double the price of cellulose.

Installation Considerations

The installation process also differs between these two insulation materials:

  • Cellulose – Can be dense-packed into wall cavities by professional installers or DIYers. Machines are needed to blow in the loose fill material. Offers flexibility for installing in sections over time.
  • Spray Foam – Requires specialized equipment, training, and safety considerations. This means installation is done by professional spray foam contractors, not DIY. The full area must be sprayed in one continuous application.

Cellulose offers a more flexible, DIY-friendly installation, while spray foam requires trained pros. Homeowners with the right tools can apply cellulose themselves incrementally. The complex spraying process makes spray foam impractical as a DIY project.

Environmental Impact

The eco-friendliness of insulation materials is another consideration for many homeowners:

  • Cellulose – Made from recycled paper waste, giving it environmental benefits for repurposing materials headed to landfills. No off-gassing or VOCs.
  • Spray Foam – Uses chemical ingredients that can off-gas during application and initial curing, raising air quality concerns. However, some brands are improving their environmental profiles.

Cellulose has better environmental credentials overall compared to standard spray foam products. However, some “green” spray foam formulations with safer ingredients are emerging.

Moisture Resistance

Preventing moisture issues is crucial for effective, long-lasting insulation:

  • Cellulose – Absorbs moisture over time which lowers its R-value. Best installed in weather-proofed envelopes or with a vapour retarder on the interior side.
  • Spray Foam – Closed-cell foam resists moisture intrusion much better than cellulose. This makes it suitable for interior basement foundations and other areas prone to dampness.

For moisture-prone areas, spray foam has superior water resistance compared to cellulose.

Sound Dampening Ability

Insulation can absorb sound, contributing to a quieter interior:

  • Cellulose – Provides decent sound dampening when installed to manufacturer density recommendations. Effective for reducing airborne sound transmission between rooms.
  • Spray Foam – Better for soundproofing because it seals all potential air gaps through which sound travels. Excellent solution for home theatres.

Spray foam is the superior soundproofing insulation.

Installing Cellulose and Spray Foam Insulation

Installation Process and Techniques
image source: indiamart.com

The process of installing insulation properly is key to maximizing its effectiveness. Here is an overview of recommended techniques and best practices for installing cellulose and spray foam insulation:

Cellulose Insulation Installation

Cellulose insulation is applied as loose fill using specialized blowing machines. The cellulose material is fed into the machine, which breaks it up and propels it through hoses to the installation area. Here are some cellulose installation tips:

  • Dense pack cellulose into cavities to 3.5-4 pounds per cubic foot. This prevents settling and reduces air gaps.
  • Insert hose into holes drilled in each cavity bay to ensure even coverage. Work methodically across the space.
  • Check depth with a ruler and pack more into any areas that are under-filled.
  • Seal access holes with rigid foam board or caulk to maintain air tightness after installing cellulose in each cavity.
  • Use masking tape to keep intake hoses secured and prevent blowback. Position hoses to minimize tripping hazards.
  • Wear proper protective gear like eye protection, mask, gloves and coveralls when blowing cellulose.

Spray Foam Insulation Installation

Applying spray foam requires special equipment and training. An experienced insulation contractor will follow these spray foam best practices:

  • Clean and mask off any areas not receiving foam to prevent unwanted overspray. Cover floors and furnishings.
  • Seal penetrations through walls ahead of time with caulk or foam backer rod.
  • Apply foam in lifts of 1-2 inches, allowing it to fully cure between passes. Multiple thin passes are better than one overly thick layer.
  • Monitor lift thickness frequently with depth gauges. Uneven application risks leaving uninsulated gaps.
  • Before spraying overhead, apply a lift to vertical surfaces so foam adheres rather than dripping or falling off.
  • Maintain proper spray distance, angle and consistent arm movements to control foam texture, density and adhesion.
  • Use fans between lifts to accelerate curing when applying multiple passes in one day.


Understanding the differences between cellulose insulation and spray foam is crucial for making an informed decision about your insulation needs. Both options offer unique advantages and considerations.

For an eco-friendly choice with excellent thermal performance and soundproofing capabilities, cellulose insulation stands out.

On the other hand, spray foam excels in air sealing and moisture resistance. Ultimately, the best choice depends on your specific requirements and budget.

Don’t hesitate to consult with a professional insulation contractor for personalized advice.

Take action now to optimize your home’s energy efficiency, comfort, and environmental impact.

Make the right call and invest in the insulation that suits you best!

About Mohammad Sameer

My name is Mohammad Sameer, the founder of SoundproofGears. My hypersensitive hearing turned me into a lifelong seeker of silence. After years of research, I've become an expert on soundproofing techniques and materials. In November 2022 I launched this site to share my knowledge and help others find acoustic sanctuary. About More

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