How to Choose the Right Insulation for Your Container

Trying to figure out how to choose the right insulation for your container?

Shipping containers have become extremely popular as alternative building types, allowing for businesses and individuals to use them for varying purposes.

Whether you’re adding on an additional storage area to your business or looking at options for a container home, insulation can be a very important decision.

But what type of insulation should you use?

Container Insulation
Photo by Charles Deluvio on Unsplash

In this article, we’ll look at how to choose the right insulation for your container.

How to Choose the Right Insulation for Your Container


Before we get into choosing the right insulation, let’s look at what insulation is?

Insulation is essentially material that is specifically designed to prevent heat energy from moving through the walls, ceiling, and floor of a building.

While most will think about residential homes when discussing insulation, this material also covers businesses as well.

Insulation helps to trap air and other gasses with a complex matrix of small cells or passages. This then reduces the role that convection plays within the air and gasses.

There are various types of insulation, which we’ll look at in the next section.

Types of Insulation


There are about 17 subtypes of insulation, which fall under 5 specific categories.

When speaking about insulation, they normally are given what is known as a ‘R-value’. R-values are the level of resistance to the heat flow that is blocked by using insulation.

Insulation is then rated by these R-values; the higher the R-value is the insulation against heat flows coming into a building.

Let’s look at each insulation category and their subtype.



This type of insulation is a bit unusual, as it incorporates non-traditional materials. However, these materials are chosen for their eco-friendliness and low-cost option.

Materials include:

  • Straw bale – similar to the bales that are usually fed to horses, stale bale insulation comes in stacks. The size of the bales only work for the exterior of a container.
Straw Hay Bale Insulation
Photo by Nick Fewings on Unsplash
  • Hempcrete – Hempcrete is similar to concrete, but is made with hemp shives and lime (sometimes sand or pozzolans).

It’s also known as hemp lime or IsoHemp.

The downside of both these types of insulation is their low R-value, between 2 and 3.




Blanket insulation is a fairly popular category of insulation. This type is usually ideal for shipping container offices and living spaces.

Fluffy and compressible, blanket insulation makes use of long fibers that is also a low-cost option and easy to install.

Varieties of this type of insulation include:

  • Fiberglass – the most common type of wall insulation, fiberglass is made from superheated sand or recycled spun glass that is turned into thin fibers.
  • Slag, Mineral, and Rock Wool – similar to fiberglass, this particular wool insulation is made from minerals, ceramics, or slag.
  • Sheep’s Wool – as it sounds, this is insulation that has been made by shearing the wool from sheep.
  • Cotton – usually made from recycled denim or blue jeans, resulting in a blue-ish color. Cotton is typically a more expensive insulation.



Loose-Fill Insulation

Loose-fill insulation is good for existing areas that have been finished, oddly shaped areas, and around barriers.

This type of insulation is common in attic areas, where insulation needs to be added or replaced. It’s installed either through blower or pouring.

There are three subtypes of loose-fill insulation:

  • Cellulose – usually made from recycled paper or paper products that have been shredded and then blown in by machine.
  • Fiberglass (loosefill) – similar to the blanket style of fiberglass, loose-fill fiberglass is less dense and not as tightly bound.
  • Vermiculite/Perlite – added to wall cavities, this type of insulation is made from minerals that have been heated and expanded like popcorn.




Expanded foam insulation is another popular category of insulation. Expanded foam, in most cases, usually has the highest R-value of insulation.

Expanded foam is created offsite, placed into boards and panels that are sized for differing wall heights. It is also self-supporting.

This insulation is do-it-yourself friendly, which can then be attached to studs or glued into a container wall.

Types of expanded foam include:

  • Open Cell Polyurethane (oc PU) – open cell foam isn’t as dense and instead filled with air. This gives the insulation a spongy texture, with a lower R-value.
  • Closed Cell Polyurethane (cc PU) – closed cell foam uses a blowing agent that fills tiny microscopic cells with a better heat conduction gas. This helps to increase the R-value.
  • Extruded Polystyrene (EPS) – composed of small fused plastic beads, EPS is the common foam you’re used to seeing in the form of coffee cups. Insulation kits are usually made from this.
  • Expanded Polystyrene (XPS) – XPS starts as a molten material that is then pressed into sheets.
  • Polyisocyanurate (Polyiso) – Similar to using polyurethane, but is more rigid.




As with expanded and blanket, spray foam insulation is also a fairly popular choice when it comes to container insulation.

Spray foam is best used for equipment enclosures that are temperature sensitive.

Containers that are being used for mobile switch rooms, UPS, generator systems, and labs usually have this type of insulation.

Spray Foam
Spray Form Insulation by FusionInsulation

Types of spray foam insulation include:

  • Open Cell Spray Polyurethane (oc SPF) – this particular spray foam is less desirable type of SPF. The reason being is due to its allowance of air movement between cells. This ends up giving it a lower R-value.
  • Closed Cell Spray Polyurethane (cc SPF) – cc SPF is the most common shipping container insulation, with a very high R-value and a good vapor retarder.
  • Damp Spray Cellulose – similar to the loose fill cellulose mentioned above, damp spray is also made from recycled paper products.
  • Cementitious Foam – an extremely light mixture of natural minerals, water, and air that is similar to concrete. It’s very eco-friendly, non-toxic, and non-flammable.

The above types of SPF are types of expanding sprayed-in insulation, while the latter two are non-expanding sprayed-in.

Expanding SPF means that it expands when applied, while non-expanding SPF doesn’t expand but does move around to fill up the sprayed area.

As you can see, there are many choices when it comes to choosing the right insulation for containers. Luckily, here are 7 factors that you can consider.

Container Insulation Considerations

1. Insulation performance affects the material, entrapped gas, or open vs closed cell structure.

2. The higher the R-value, the better prevention of heat energy transmission.

3. Consider the net interior space, which is directly correlated to the R-value. This is how much space is left over in the container after accounting for insulation.

Southwest Mobile Storage Container Office Interior

4. Ensure that the shipping container insulation is able to protect against air leaks from flowing through and around any edges.

5. Also ensure vapor permeability, which prevents vapor from migrating through and staying within the insulation.

6. Cost is of course an important consideration when it comes to insulation. Be sure to factor in material costs, labor, and equipment.

If you’re concerned about sustainability, you’ll want to consider eco-friendly insulation.

If this seems like a lot, don’t worry!

Insulation can be combined in the same container. This allows you use a specific type of insulation on one part of the container and another type in another area.

If you still have questions about container insulation, contact us at 800.686.9114 or fill out the form below.

Our shipping container experts can help narrow down the different options for your container project!