Why use closed cell insulation?

Insulation is a critical component of energy efficient and comfortable homes and buildings. There are many types of insulation materials available, but closed cell insulation has emerged as an excellent choice for many applications. Here we’ll look at what exactly closed cell insulation is, why it’s effective, and the main benefits it provides.

What is closed cell insulation?

Closed cell insulation, also sometimes called rigid foam insulation, is a type of insulation made up of small, sealed foam cells. The cells are closed and filled with a gas that provides the insulation properties. The gas has low thermal conductivity, which prevents heat transfer effectively. The closed cell structure also resists moisture and air infiltration quite well.

Closed cell insulation is commonly made from polyurethane, polyisocyanurate, or extruded polystyrene (XPS) foam. These materials provide the tiny closed cells that make closed cell insulation effective. The small cells act as pockets of air that slow heat transfer through the insulation.

The closed cell structure gives this type of insulation additional benefits compared to open cell insulation. The closed, non-breathable foam cells minimize air leakage and maintain the insulation’s R-value (its ability to resist heat flow). The foam also resists moisture absorption better than other insulation types.

Why is closed cell insulation effective?

There are a few key properties that make closed cell foam ideal for insulation:

• Higher R-value per inch – Closed cell foams provide an R-value of around R-6 to R-8 per inch of insulation. This is two to three times higher than most other insulating materials.
• Air sealing – The closed cells prevent air flow through the insulation, greatly minimizing air infiltration.
• Moisture resistance – Closed cell foams are also water-resistant and don’t absorb moisture easily.
• Rigid structure – Closed cell insulation provides a solid, rigid material that can support itself and hold its shape.

These characteristics allow closed cell insulation to insulate extremely well and block moisture and air leaks. The higher R-value per inch means the insulation doesn’t have to be nearly as thick to achieve desired insulation levels. The smaller thickness also allows it to fit into tight spaces in existing constructions.

Main benefits of closed cell insulation

Using closed cell insulation provides many benefits for your home or building project. Here are some of the top advantages:

High insulation value

The high R-value (6-8 per inch) of closed cell foam allows it to insulate 2-3 times better than materials like fiberglass (R-3 per inch). You can achieve target insulation levels with thinner foam, allowing it to work in confined spaces.

Air sealing

Closed cell’s air tight structure prevents drafts, leaks, and air infiltration. Preventing air leaks is just as important as insulation for energy efficiency. Closed cell foam blocks air movement and reduces heating/cooling losses.

Moisture resistance

Closed cell foam resists moisture accumulation and rotting better than many other insulations. Materials like fiberglass can absorb moisture over time and lose their insulation value. Closed cell’s moisture resistance helps it retain optimal insulation performance.

Adds structural stability

Unlike fiberglass or cellulose, closed cell foam is very rigid. When installed properly, it adds structural stability and strengthens the building envelope. This extra structural strength is useful for retrofits or for lightweight construction.

Long-lasting insulation value

Closed cell doesn’t tend to settle or degrade over time. As long as it’s properly installed, it will retain its full R-value for over 50 years. You get excellent long-term insulation with minimum maintenance required.

Versatile applications

Closed cell can be installed in walls, roofs, foundations, and many other building cavities. Specialty forms like foam boards work great for exterior sheathing. The rigid structure holds its form for a consistent insulation barrier.

Where should you use closed cell insulation?

Closed cell insulation works very well for many common applications:

• Exterior walls – Provides insulation and air sealing in framed walls.
• Attics – Can be applied directly to roofs/ceilings for uninterrupted insulation.
• Foundations – Closed cell foam boards (XPS) work great for exterior foundation insulation.
• Unvented attics – Closed cell is one of few insulations approved for unvented attic assemblies.
• Basements – Insulates basement walls and helps minimize moisture issues.

It’s a versatile solution for any area that needs insulation and air sealing. The rigid foam boards are also easy to cut and install in confined spaces.

What are the main closed cell insulation types?

There are a few different types of closed cell foam used for insulation:

Spray foam

Spray foam (polyurethane or polyisocyanurate) is applied as a liquid that expands and cures as a rigid foam insulation. It can fill cracks and crevices for a complete air seal and insulation barrier.

Rigid foam boards

Foam board products like XPS (extruded polystyrene) provide closed cell insulation in convenient rigid boards. These boards work well for exterior sheathing or foundation insulation.

Insulating concrete forms (ICFs)

These foam forms are used to pour concrete walls. The foam provides closed cell insulation on the interior and exterior of the concrete.

Each of these closed cell products has advantages in certain situations depending on the application requirements.

What are the disadvantages of closed cell insulation?

Closed cell insulation also comes with a few disadvantages to consider:

• Higher cost than some other insulation types like fiberglass.
• Spray foams require special equipment and contractor expertise to install correctly.
• Can deteriorate if exposed to sunlight and moisture over time.
• Rigid structure and thickness may require adjustments to accommodate.

Proper installation and protection are important to get the full benefits of closed cell insulation. The higher initial cost may also be offset by energy savings over time.

Cost to install closed cell insulation

Closed cell insulation costs more than basic insulations like fiberglass. Here are typical price ranges for closed cell installation:

Insulation Type	Cost per Square Foot (Installed)
Closed cell spray foam	$1.50 – $3.00
Rigid foam boards	$0.70 – $2.00
ICF concrete forms	$5.00 – $8.00

Many factors affect overall costs, including existing insulation levels, accessibility, project size, and labor rates. Get multiple quotes to find the best deal from qualified installers.

Should you choose closed cell insulation?

Closed cell insulation provides unmatched insulation value, air sealing, and durability. It’s an excellent choice for:

• New construction projects
• Attic and basement retrofits
• Home additions
• Concrete foundation insulation
• Unvented, conditioned attics

Consider closed cell insulation if you want long-lasting, highly efficient insulation. It requires careful installation but can significantly improve your home’s thermal performance when done properly.

Conclusion

Closed cell foam provides an insulation option that stops air and moisture while adding structural strength. The closed cell structure gives it an exceptionally high R-value per inch. It works well in confined spaces where high insulation levels are needed. Despite the higher initial cost, closed cell insulation can save money long-term through energy efficiency and durability.

Pay attention to proper installation requirements to get the full benefits of closed cell’s insulation value, air sealing properties, and moisture resistance. It’s one of the best options for new construction or renovations focused on energy efficiency and comfort.