Upgrading your insulation but stuck on the choice between open cell vs closed cell foam? 

Many homeowners face this confusion when weighing comfort, energy savings, and long-term durability against cost. 

Pick the wrong option, and you could overspend without getting the results you need. Pick wisely, and you can enjoy lower energy bills, better air quality, and peace of mind knowing your home is protected.

Also it can’t be your next DIY project. Contact a professional to rescue your home for you.  

The difference between open and closed cell foam is easier than you might think. 

By looking at cost, performance, R-Value, moisture resistance, and application type, you can make a decision that truly fits your home and budget. 

Open Cell and Closed Cell Foam Insulation

Before diving into pros and cons, let’s start with the basics of open cell and closed cell foam insulation. Both are types of spray foam created by mixing chemicals that expand into a thick foam. This foam is then applied to walls, ceilings, and crawlspaces to seal gaps and stop air leaks.

The main distinction comes from their cell structure. 

Open cell foam contains tiny bubbles or cells that are not fully closed, leaving space inside each cell. This makes the foam softer, lighter, and more flexible. 

Closed cell foam, on the other hand, has cells that are completely packed together, creating a denser and more rigid material.

That structural difference is what drives all the variations in insulation performance, from cost to moisture resistance to energy efficiency.

The Difference Between Open and Closed Cell Foam

When homeowners ask about the comparison between open cell and closed cell foam, they’re really asking about performance trade-offs. Let’s explore how the two types differ in key areas.

1. Density and Rigidity

• Open cell foam is lightweight and flexible, with a density of about 0.5 pounds per cubic foot.
  
• Closed cell insulation is much denser, usually 1.75 to 2.2 pounds per cubic foot, and adds strength to structures.

2. Moisture Resistance

• An open cell absorbs moisture more easily. While some open cell foams are designed to resist water, they are still more vapor-permeable.
  
• Closed cell foam creates a solid moisture barrier, making it ideal for basements, crawlspaces, and flood-prone areas.

3. Soundproofing

• Open cell foam excels at sound dampening because of its softer, porous structure.
  
• Closed cell foam is more rigid, so it blocks less sound compared to open cell.

4. Expansion

• Open cell foam expands up to 100 times its size, filling cracks and gaps easily.
  
• Closed cell foam expands about 30 times, requiring more precision during application.

5. R-Value

• R-Value measures thermal resistance, or how well insulation keeps heat in or out.
  
• Open cell foam typically has an R-Value of 3.5 to 4 per inch.
  
• Closed cell foam averages around R-6 to R-7 per inch, making it far more effective in thin spaces.

Benefits of Open Cell Foam

Many homeowners appreciate the benefits of open cell foam, especially when budget and soundproofing are top priorities.

• Open cell foam is less expensive than closed cell foam because it uses less material.
  
• Perfect for attics, wall cavities, and tricky areas.
  
• Its softer structure absorbs sound waves, keeping rooms quieter.
  
• While it allows vapor through, it can still regulate indoor comfort effectively.
  
• It requires fewer raw materials compared to closed cells.

Benefits of Closed Cell Foam

If strength, durability, and moisture resistance are important, the benefits of closed cell foam are hard to beat.

• Provides almost double the insulation performance per inch compared to open cells.
  
• Stops water and vapor, preventing mold growth.
  
• Adds rigidity to walls and roofs, improving building durability.
  
• Recognized by FEMA as flood-resistant, making it a smart choice for areas prone to water damage.
  
• Can be applied outdoors, on foundations, or in metal buildings.

Cost Considerations: Spray Foam Insulation Cost

One of the biggest questions homeowners have is about spray foam insulation cost.

• Open cell foam generally costs less per board foot because it uses less material and expands more.
  
• Closed cell foam is more expensive upfront due to its density and higher material volume.

That said, cost should not be the only deciding factor. A cheaper option that does not perform well in your climate or space may end up costing more over time through higher energy bills.

Injection Foam Insulation vs Spray Foam Insulation

When comparing injection foam insulation vs spray foam insulation, it’s important to note how each is applied.

• Spray foam insulation is sprayed directly into open cavities, expanding on contact to seal gaps. It is ideal for new construction and remodels where walls are accessible.
  
• Injection foam wall insulation installation works best in existing walls. Instead of tearing down drywall, small holes are drilled, and foam is injected into the cavity. This makes it a great retrofit option without major disruption.

Both methods use similar foam technology, but the application process depends on whether your project is new or existing construction.

Where to Use Open and Closed Cell Foam

Choosing between open and closed cell foam often comes down to location in the home.

• Attics and interior walls open cell works best here thanks to its expansion ability and soundproofing benefits.
  
• Basements, crawlspaces, and foundations are closed; cell insulation is the clear winner because it resists water and provides structural strength.
  
• Metal buildings and pole barns closed cells help reduce structural flex and resist condensation.
  
• Soundproofing projects can open cells is the go-to choice for home theaters, offices, or noisy neighborhoods.

Common Misconceptions About Spray Foam

Many homeowners believe that one type of foam is always better than the other. In reality, both have unique roles. 

Some think that because a closed cell has a higher R-Value, it automatically means better insulation everywhere. 

However, if your main concern is soundproofing or budget, open cells may actually perform better in your situation.

Another misconception is that foam always absorbs water. While an open cell is more vapor-permeable, high-quality foams are designed to resist mold and moisture damage.

Which Should You Choose?

So, which insulation wins the open cell vs closed cell debate? The answer depends on your project needs.

• If you want affordable insulation with great soundproofing for interior spaces, go with an open cell.
  
• If you need maximum strength, water resistance, and higher R-Value in limited space, choose a closed cell.
  

If you are still unsure which foam insulation fits your home best, it may be time to talk with professionals. 

Contact WeatherFoam today to schedule an inspection and discover how the right insulation choice can make your home more energy-efficient, comfortable, and durable for years to come.