Insulation is the material that separates you and your comfortable room of conditioned air from the extreme temperatures outdoors. When thinking through how to insulate a shipping container, there are quite a few options insulated container example with their own pros and cons.

You likely need insulation for your shipping container home, but what kind of insulation is best? The answer can vary depending on your situation and goals.

In this Article

This article will answer all your questions about shipping container insulation. Storage container homes are popular these days, but you need to know what it takes to truly turn them into a living space.

We will first examine the most relevant considerations in choosing a type of insulation, then we will examine the insulation types you can choose from, and we will conclude with some insulation alternatives.

You may have heard that polyurethane spray foam insulation is the only variety worth considering for shipping containers. As you’ll find out below, that’s not insulated container vs reefer container always the case.

Our goal with this article is to give you a comprehensive guide to not only understanding insulation generally but also how to choose the type of insulation that is most relevant to your needs. This can include factors such as the size of the container, geography and climate, as well as insulation-specific attributes like price, quality, and more.

With that said, let’s start with a discussion of controlling factors and the various types of home insulation.

What is Insulation?

If you had an open-air porch or patio that is hot in the summer, would you air-condition it? Not without enclosing it by building walls first, of course!

You want to keep the conditioned air (air that has been intentionally cooled or warmed, depending on the season) separate from the outside air. Otherwise, you’re air conditioning the neighborhood (something you may have heard from your parents when you left the front door open!)

If you built the walls around your porch out of newspaper or plastic food wrap, they wouldn’t be very effective at regulating the temperate (even though they would keep the air separated). Why not?

A thin wall isn’t able to prevent the transfer of heat from the warm side to the cool side very effectively. While the special container actual air can’t move through the wall, the heat contained in the air CAN move through the wall material. So even though the air is seperated, your energy efficiency would be quite low. We’d recommend checking out our article on heat transfer in container homes before you go any further if you’re not clear on any of the concepts so far!

Therefore, insulation is a material specifically designed to prevent heat energy from moving through the walls (and ceiling, and floor) of your shipping container home. It generally works by trapping air or other gasses in a complex matrix of tiny cells or passages.

Compared to solids and liquids, gases conduct thermal energy poorly, making them excellent insulators. By confining the gases to millions of tiny cells, you reduce the role convection plays within the gas, further increasing the material’s insulating properties.

In most cases when we talk about thermal insulation, we’re specifically talking about conductive (and to a lesser extent, convective) heat flow. The resistance to this heat flow is measured using an “R-value”, which coincidentally is how insulation is rated (higher is better). Heat flow via radiation does come into play as well as discussed below.

An important note for our readers that use the metric system (SI units): The R-values expressed in this article, elsewhere on our website, and in most American publications are based on English or inch-pound units. To convert to an SI R-value, you need to multiply by 0.1761101838. Read this Wikipedia article for more information on the unit conversion.

Why do you need container home insulation?

When insulating a shipping container, you’re separating the conditioned airspace from the outdoors. It’s the same thing you’d normally do with almost all enclosed structures that have climate control. As explained before, insulating material helps keep the heat from the warmer side from moving to the cooler side. This increases the energy efficiency of your container home by lowering the amount of energy needed to regulate the internal temperature.

Unlike some more traditional types of residential construction, shipping container homes have the added issue of an exterior that is completely made of steel. Given how great steel is at conducting thermal energy, it is especially ineffective at keeping your airspace at a different temperature than the air outside. Therefore, insulation is often needed more for shipping container homes than for other construction types.

And let’s not forget that the steel of a container home can absorb a tremendous amount of radiant energy from the summer sun, actually getting hotter than the ambient air. Simply stated, unmodified shipping containers are great at keeping outside air from getting inside. However, they perform poorly at keeping heat from moving through their walls.

Nevertheless, just because container homes are bad at preventing heat transfer doesn’t automatically mean you need insulation. The other factor to consider is the climate.

How climate affects your insulation decision

If you are lucky enough (or easy-going enough!) to live in a location with a climate that is suitable for you to live in without additional cooling or heating, you may not need insulation material for your shipping container. Areas like southern California and parts of the Mediterranean feature what many consider to be an ideal climate.

With that said, some people still need heating and air conditioning in these climates…and thus should strongly consider insulation. Whether you will need climate control for your shipping container home or not depends on your personal preferences for what is ‘comfortable’. With additions of fans in warm climates and warm clothes in colder ones, you may be able to endure the normal temperatures without any added insulating material.

If you don’t live in such a location, then we strongly recommend you insulate your insulated container for food storage containers, but you don’t HAVE to. You’d need to weigh the costs of insulating (a one-time cost) versus the ongoing heating and cooling costs to run your air conditioner and/or heater.

You might also need a larger air conditioner or heater than you otherwise would if you had insulated your container. Over time, any money saved from not insulating quickly disappears as you pay more and more for energy to keep the climate in your shipping container tolerable.

To summarize, unless you live in the best possible climate, you are likely going to need to insulate your cargo container. And if you choose to forgo insulation, there’s a real chance you will regret it due to all the extra money you will need to be spending on heating and cooling. You will definitely appreciate the benefits of an insulated shipping container far more often than not.

One note of caution: If you don’t insulate your container, not only will your home be harder to heat and cool, it may also be susceptible to water condensation, which can lead to an assortment of problems like corrosion and mold. Our article on condensation discusses this in-depth and is a must-read for all prospective shipping container homeowners.

Where to place your container insulation

Most building types have multiple layers of materials in their walls. The surface you see inside is not the same material as what’s outside. In between are several layers of materials that provide structure, fire resistance, weatherproofing, thermal insulation, vapor barrier, etc.

With shipping container homes, the container itself is one such layer. And you have to make a decision on where the container skin will be located in the overall wall system.

The most conventional answer is to place insulation within the interior walls, inside the shipping container. These stud walls are added to most designs anyway as a place to run plumbing and electrical service, as well as an attachment point for drywall or other interior surfaces. It only makes sense to add insulation in the cavities between the studs. Then you can more or less leave the outside of the container as-is if you want.

However, for some people, exterior insulation is a better fit. In this case, you place insulation outside of the container and then cover that insulation with some type of weather-resistant sheathing. This provides the benefit of increased interior space and a more controlled exterior appearance for those who want to shield or hide the shipping containers themselves.

Factors to consider when choosing shipping container insulation

Deciding on the best insulation for your home is less straightforward than you think. Each type has pros and cons that may or may not be especially relevant to the specific conditions of your shipping containers.

We’ll do our best to provide a high-level discussion of some of these criteria as we go through each type of insulation. However, know that there can be some variability depending on region and manufacturer, so always do your own research.

Main factors to consider when evaluating your insulation options include:

Overall Performance: Performance characteristics are affected by things like material, entrapped gas, open non working reefer container for sale vs closed cell structure, etc.

R-value: How well the material prevents transmission of heat energy for a given thickness

Air Leakage: How well the insulation prevents air from flowing through it (which as already