We’re often asked about refrigerated shipping containers, commonly known in the shipping industry as reefers. As we’ve already discussed, one of the primary issues encountered when building a container home is adding insulation. Without insulation, your container will be noisy and, more importantly, uncomfortably warm or cold depending on your climate.
Refrigerated shipping containers are a crucial part of the “cold chain”, a parallel supply chain that handles temperature controlled goods. Products like meat, dairy, fruits, vegetables, and even flowers and pharmaceuticals often depend on the cold chain. If you’ve ever wondered how you’re able to buy fruits out of season, for instance, you can thank the invention of the refrigerated shipping container.
So, when looking at the various types of containers available, it’s natural to wonder if a refrigerated shipping container might be a better starting point than a traditional shipping container. A refrigerated shipping container is already insulated, saving you the time and expense of doing this step yourself, right? Well, the answer is a little more nuanced.
Let’s dive into a few aspects of refrigerated shipping containers, and see how they “stack up” to regular shipping containers (and yes, that was a container joke about stacking!)
The primary motivation people have for investigating the use of a refrigerated shipping container for their container home is cost. The thinking is, if you can buy a refrigerated shipping container for just slightly more than a regular container, you wouldn’t need to pay to insulate it, and you’d come out saving money overall. Whether that’s true or not depends principally on how cheaply you can acquire a refrigerated container.
Broadly speaking, refrigerated containers cost around 50% more than the same size standard container. However, this figure depends greatly on where you are in the world and the prevalence of refrigerated shipping containers there.
In order to talk about size, we first need to understand type. There are actually two types of refrigeration systems used in refrigerated containers:
- Integrated (refrigeration equipment attached to and within the size footprint of the container)
- External or Clip-on (refrigeration equipment that is temporarily attached to or otherwise placed near the end of a container, with ductwork feeding into and out of the container via portholes)
When most people think of refrigerated containers, they think of the integrated type, but it’s important to understand that it isn’t the only option. However, for the purposes of this article, assume that when we say refrigerated container, we’re referring to the integrated type.
Refrigerated containers are available in most of the standard container sizes, including high cube (HC), so there is no issue with them interfacing with regular containers. However, what CAN be a problem is internal floor area.
Given that the refrigeration equipment is integrated into the container, it has to fit somewhere. That somewhere, as shown in the picture above, is the end of the container. Approximately the last two feet of the container is dedicated to refrigeration equipment, leaving your interior two feet LESS long. While two feet may not sound like much, it can be up to 5-10% of the length of your container, and correspondingly up to 5-10% of your floor area! What might you have to sacrifice in your design to account for this two extra feet? A closet? A couch? While this sacrifice can be worked around, it’s certainly something to consider.
Maybe you’re thinking to yourself, “What if I just remove the refrigeration equipment and reclaim the two feet of space that’s rightfully mine!?” This is an option, but not without its own issues. If you’re going to be reusing the refrigeration equipment (and we’ll address that below in the next section), you would need to fabricate a stand to hold the equipment, as the container would no longer be supporting it. You would also have to extend ductwork from the refrigeration equipment to the container. However, probably the biggest issue of removing the refrigeration equipment and reclaiming the space is how to add the new open space to the existing closed space. To start with, you’d have to cut the end cap out of the container, push it out two feet and reattached it to the frame. Then, you’d need to get two additional feet of exterior sheeting, insulation, and interior sheeting to cover the sides, roof, and floor. Clearly, it would be a major undertaking, and you may have trouble getting your two-foot addition to match the rest of the container.
Besides the two feet taken up by the refrigeration equipment, you also need to factor in the thickness of the insulation. A typical refrigerated container has 3-4 inches less interior width than a standard container. However, if you’re going insulate your container anyway (and you should!), this shouldn’t be a concern, as your self-installed insulation would likely take up about the same space.
As previously mentioned, refrigeration equipment sits within the confines of the container’s external envelope, but outside the enclosed space. The refrigeration equipment, much like your home refrigerator or air conditioner, is made up of mechanical equipment that requires electricity to operate.
When you buy a standard container, it has no moving parts other than the door hinges, so there isn’t too much that can break. However, a refrigerated container’s mechanical system has more ways to fail. Assuming you don’t plan to use it, that’s not a concern. Many people go this direction and purchase NORs: Non-Operational Reefers. However, if you DO have aspirations of reusing the refrigeration equipment, it may need some repair work.
More important is how you would go about powering it. Most refrigeration containers are designed to receive electrical power from the ship during sea transit, and from the port while ashore. During land transit, they are typically powered by diesel generators called gen sets. The electricity service needed is usually high voltage three phase. This is a more efficient method of power delivery for large industrial uses, as it allows the same amount of power to be transmitted across smaller diameter conductor wires. However, most residential electrical service does NOT have this type of electrical power available. In order to use the refrigeration equipment, you need to modify or retrofit some of the subcomponents with alternatives that are compatible with the electrical service in your geographic area.
Most refrigerators and air conditioners take advantage of a thermodynamic process known as the vapor-compression cycle. The cycle depends on specific components such as a compressor, evaporator, condenser, and expansion valve. But the real magic of the cycle is the refrigerant, a special chemical that is the cycle’s working fluid. Unlike water that boils at 100⁰C (212⁰F), refrigerants can boil at a much lower temperature, which is what enables them to absorb heat from a warm room. Without getting too technical, just know that coupled with a refrigerant’s incredible utility for cooling is the fact that it is poisonous and harmful to the atmosphere. If you choose to purchase a refrigerated container and don’t use the refrigeration equipment, it’s best to have a professional help you collect and dispose of the refrigerant, as these systems can and do leak over time.
Unless you’ve seen a refrigerated container in person, you may not be aware of the design of their flooring systems. While traditional containers have plywood floors, refrigerated containers have special metal (usually aluminum) floors. This flooring system, called a T-floor, T-grating, T-style floor, or T-section floor, has a T-shaped profile that keeps the contents of the container elevated so that cold air can flow underneath.
The unmodified T-floor is not suitable for a container home, given the deep channels it contains that would hold dirt and catch the legs of your chairs and the toes of your shoes. Therefore, you would need to either put another floor on top of the T-floor, or tear the T-floor out and replace it. Given that most people either replace the existing plywood floor or seal it in a typical container, modifying the floor in a refrigerated container isn’t necessarily more work, and you shouldn’t have to deal with the nasty chemicals that manufacturers use on the plywood floors of traditional containers.
Nevertheless, we recommend you think through this and have a plan in place that takes into account the time, expense, and interior ceiling height impacts of any modifications you are contemplating.
If you’re in a cold climate and have considered using radiant floor heating, the T-floor may be an advantage. With some modifications, you could use the channels to hold the water pipes for your radiant heat system, and then place plywood or other flood covering on top of the T-floor.
One final thing to consider on a refrigerated container is the walls. Unlike traditional containers with corrugated steel walls, a refrigerated container typically has walls made of a sandwich of stainless steel sheeting, foam insulation, and aluminum sheeting. This sandwich is usually smooth on both the interior and exterior of the container, which provides a different aesthetic than corrugated steel. Depending on your design and appreciation for different visual styles, this may be a pro or con for you.
Cutting through that sandwich for doors, windows, and utility penetrations isn’t much more difficult, but you do need to make sure your interior and exterior holes match if you don’t have a cutting method that can cut through the sandwich in a single pass. If you’re planning to use a torch or other similar method for cutting, you also need to be very careful about burning the foam.
Walls are also where most of your electrical outlets and plumbing fixtures are mounted. In standard container construction, you’d hide plumbing and electrical lines inside the interior walls where the insulation is placed. Given that the walls of a refrigerated container are already built, you could cut through part of the wall sandwich (and remove the insulation) in order to place your lines, then cover over your cuts with new sheeting. Alternatively, you could just surface mount the lines on the interior of the wall sandwich. The first option is a lot of work, while the second will likely be unsightly.
As you can see, the decision on whether to use a refrigerated container for your container home is influenced by several factors that you may not have considered. Hopefully, this discussion will help you better understand the impact this decision will have on your build. Unfortunately, with the great variability of prices and conditions of refrigerated containers, there is no universally correct answer on whether or not you should use a refrigerated container. Instead, weigh the various factors and make the best decision for you, your build, and your geographic area.
Additionally, one related item that we haven’t touched on in this post is insulated, unrefrigerated containers. These containers have no refrigeration equipment, and instead, rely on dry ice or other liquid vaporization processes that provide a finite amount of cooling over a few days or weeks. If you can find one of these containers, depending on other factors, it may make more sense for you than a refrigerated container.
Have you built a container home out of refrigerated containers, or planned to use one then changed your mind about doing so? We’d love to hear about your experience in our comment section below.