Should you use a Refrigerated Shipping Container for your Container Home?

Should you use a Refrigerated Shipping Container for your Container Home?

Posted By: February 5, 2018 In Featured

Want to build your own shipping container home? Start Here.

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!)

Cost

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.

Size

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)

Integrated Refrigeration 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)

 

External Refrigerated Container

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.

Refrigeration Equipment

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.

Refrigerant

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.

Flooring

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.

T-section floor
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.

Walls

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.

Summary

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.

Comments
  1. Pierre Combrink

    I would like to know if anybody has used the internal pipes of the reefer to run water through it to be used like under floor heating?

    • Tom

      Not sure what you mean by “internal pipes”. The reefer doesn’t have pipes running through it with fluid in them. All the cooling equipment is contained in the cooling unit on the end, and cool air blows through the container. The cooling unit itself would have some copper pipe in it that containers the refrigerant, but dismantling the unit, disposing of the refrigerant, and trying to use the pipe is a lot of work and mess for not very much benefit.

  2. Patrick

    Anyone have on details on the structure for the reefers? Do they have a HSS tube frames with posts in the corners? Are there beams in the roof and floor?

    • Tom

      While we haven’t seen one completely deconstructed and taken down to the frame, our understanding is that reefers are pretty similar structurally to other container types. Per ISO 1496, they are required to support the weight of eight loaded containers (among other static and dynamic loading tests).

  3. Sandra

    Hi, do you know what the actual “R” value is of a Reefer? Cutting a hole in the wall for the windows, the supports in the walls, do you know how far apart they are, in a Reefer?

    • Tom

      The answer to the R-value question is tricky. ISO 1496, which gives the specifications for insulated/refrigerated shipping containers, does not prescribe R-values, and instead gives a testing procedure for manufacturers to follow. We can infer the R-values by looking at the minimum allowable interior dimensions (which corresponded to maximum allowable wall thickness, as the exterior dimensions are fixed). There are two classes of insulated containers, with maximum allowable wall thicknesses of 9cm and 11cm. Different manufacturers may use different types of insulation in order to pass the test, but the highest performing insulations (like closed-cell spray foam) have an R-value around 3 per cm. So, that would imply that your wall would at most have an R-value of 27 to 33, depending on class of container. Note that this excludes the insulating performance of the interior and exterior metal surfaces. Also note that this is the maximum, but manufacturers may be able to pass the ISO 1496 test with less. Finally, note that the thickness is typically not consistent between sides, ends, floor and ceiling. We’re simply trying to give you some rough numbers here, but these can vary based on manufacturer.

      As far as internal supports in the wall sandwich, this isn’t specified in the ISO 1496 standards, though in many cases there may not be any internal supports at all to minimize thermal bridging between the interior and exterior of the container.

  4. Gary Central Victoria Australia

    Tom appreciate your site and checking out other people’s ideas.
    REEFERS I already have two and have visions of using several more as the basis of a home.
    There seems to me so many reasons why, I almost don’t understand how come more people haven’t discovered them
    1. Apart from the obvious of insulation, to me they are ascetically better. a0 you could spray a concrete render on them and disguise the external appearance and they will not look like a container
    2. The T channel in the floor seems a bonus and is almost designed for an underfloor heating system of pipework and then pour your slab over it polish it and, voila.
    3. Reefers having carried foodstuffs are unlikely to have been fumigated by lord only know what poisons
    4.the side walls are stainless steel and can be used as such, so a pretty chill interior at little cost
    5. Hicubes, make sense, a sense of space and not pulling down the ceiling onto you. bit claustraphobic feeling is low ceilings
    6. The structural aspedct of reefers, seems to me to be of a ribbed design with the insulation placed between these ‘metal joists’. So cutting in windows or doors is so much easier. Whereas the the strength of the standard container is in the wave of hgte material. Once you cut out door and window spaces you lose strength and start talking to expensive engineers.
    7. At the moment I have 2 NOR Reefers, used as storage for cars and shed. NOR’s arte cheper, because they are Non Operational Reefers
    8. Finally, I have made a bunch of scaled wooden blocks. Just leave then on the kitchen table, and it is interesting to see (in concret operational form) what shapes and external house designs look like. So easy to work as mock up models.

    (I have considered with several NOR reefers I might be able to build a good working refrigeration system very economically)

    For me, and the above reasons I think reefers are the cat’s whiskers

    cheers Gary M
    s

    • Tom

      Gary,

      Great to hear about your success with refrigerated containers. We’ll be making a few updates to the article in response to some of the points you and other readers have brought up. Thanks for helping out the container building community!

  5. WIll

    I’m building in a Hi Cube 12 metre (reefer).
    Because its a Hi Cube, I have chosen to cut out some of the “T” floor beans so as I can form a channel which will house all plumbing, Heating radiator pipe work, and drainage which will still have sufficient fall to allow me to drain 2 hand basins, shower, bidet and kitchen sink through one outlet, through a hole in the LH door.
    The Rayburn solid fuel cooker/range is the source of heating and cooking and the cast iron radiators have a return pipe for the heat spent waters. That return pipe along with the hot and cold water supplies to hand basins and shower will be in the 250mm (10 inch) wide channel which runs the length of the reefer.
    There will also be 100 x 50mm (2″x4″) flooring joists supporting a plywood flooring. I amy be going over board” so to speak but all the timber will be treated timbers.
    Actually, something that that others may be wise to know of, (and which I previously didn’t know of) is that the timber treatment of Pinus Radiata, (H3 & H4) which I understand is copper based, reacts negatively with steel and galv coated nails, so all fixings have to be made of stainless steel.
    The ply flooring is glued and screwed with S.S. screws.
    The strip where the plumbing is is all accessible by lifting out specifically cut ply strips which will be 310 wide and is the same width as a cork tile.
    The flooring will be cork tiles for a number of reasons. Insulation qualities, quietness & comfortable underfoot and ease of cleaning to help keep the homes dust mites at bay.

    Insulation ratings of the Insulated reefer is extremely good. The plane has always been to have a very warm home as well as having a highly economic & effective heating as well as excellent heat retention of our new home. After the time researching it, I decided that this Reefer was the way to go. Putting fluffy fiber-glass or even spraying foam about just wasn’t as good as with a system that the reefers come with. Urethane type insulation is ‘tops’ when it comes to R ratings & especially when its as thick as the reefer’s walls are!

    I find it excellent for noise reduction as well.

    I will be adding a solid native New Zealand timber to the walls of the rooms I construct. Its Rimu TG&V and then coating it all with oil based polyurethane.

    The position of the final resting place is close to an electricity supply but we will be off grid totally but will have a 240 volt Genset plus solar panels for a 12 volt system.
    The two sets of wiring systems wire will run in a suspended ceiling and in the ceiling cavity will be a sheet metal ducting system to extract dunny smells. shower steam and cooking fumes to an outside outlet.
    In the same ceiling cavity will be the delivery plumbing for the heating radiators.

    Anything that needs to be attached to the metal walls or ali ceiling, will be held in place with the use of threaded Rivnuts.

    The original reefers refridgeration system will be removed to gain the extra space and to make access into another reefer which will be used for storage and possibly part of a workshop.

    If you have any questions, feel free to ask.

    Regards
    Will

    • Tom

      Will, sounds like a great project. Thanks for sharing some of your insight here. We’d love to hear (and see) more of the project when you get further along, so please do reach out via our contact page!

    • Simon

      Hi Will

      Would I love to learn more about what you are doing. We live in Rotorua and have plans to convert an old 12m Reefer as well. Where about’s in New Zealand are you?

      Cheers
      Simon

      • Will

        July ’18 Sorry Simon, I haven’t been back to this web site for some months hence no reponse to where I am.
        I’m near Darfield, Canterbury
        I have recently had more & more time to get back to the Reefers conversion and Im really happy with the progress.
        A cobber is making a Youtube clip of the conversion but it might take a year to get it all sorted and posted.

        I have re-read the description of Reefers by Tom and I’d recommend that he needs to work on one and understand they type of insulation they have in them, as well as the structural integrity & materials of a Reefer as well as measure up the space that the refrigeration unit is taking up, plus its removal.
        I have 4 x 40ft Reefers and the refrigeration units of them on them take up about 350mm (14″ )
        As well as that, they are all held in there, by a series of nuts which are able to be undone with either nut crackers (which splits the nuts) or with a half inch drive socket set with an extension, such as a bit of 3 or 4ft pipe to get greater leverage.
        IF all of the nuts are removed, then ideally a tractor with a front end loader (with forks attached) or a fork lift would be most definitely helpful with its removal. Otherwise, a tug with a tow rope attached to a ute (small truck for them yanks) is highly likely to do the deed and then, just keep dragging it to a metal recyclers.

        Then you have a hole to fill. The studs that were holding the refrigeration in place are able to be used to secure the End Blanking Cover’s material. Easy!
        Then the inside is lined clean and more internal space available for cupboards or whatever. OR…. you could have another door or Bi-fold door or ranch-slider put in that end as well!

        I am also about to cut into the side of the Reefer to put Bi-fold windows and a servery to a deck outside.
        Also I’m working at cutting a hole in the side to install a couple of lead-light swing doors.
        These doors will allow access (& heat from the Rayburn cooker) through into the living area which is part of the separate living and bedroom area. This is also a temporary moveable building which will be made of KINGSPAN panels)
        I have considered using some of that Reefers waste material which came from where the the leadlight doors and Bi-fold windows are, to fill in the hole where the refrigeration set-up was but I want it to look tidy and also, its likely to take too much time sorting it. So…. so as to keep the Reefers same high R Rated insulation, I’ll look at attaching some Aussie made but European designed KINGSPAN (80mm thick) insulated panels in there.
        I wouldn’t use closed foam or polystyrene. Ive waited to be able to afford better quality insulation with a much higher R rating.
        Kingspan is pretty expensive but hey, I want this to last 30 to 50 years! (shhhhh, its temporary)

        The Bi-fold window in the Reefers kitchen will have a thermal break built into the frame as well. (as do the other units french doors)

        I really do hope folks wanting to build a home (or hut) in a shipping container, will seriously consider using a Reefer. The extra dollars invested when buying it, I feel SURE will be paid back with ease of setting it up and temperature COMFORT.

ADD YOUR COMMENT