A/C Size for Shipping container?

[Stuka]

I've never bought a window unit before, so I am researching what I need. I have a 40 ft shipping container, with an 8 x 11 foot section walled off at the end opposite the big doors.

I am looking to cool the room section to about 76. It's about 88 square feet. The window units are rated by BTUs and the vendors list suggested room size, such as this one from Lowes. Yeah, that seems like a lot of AC for a small room, right? I intend to add Foam it Green to the exterior walls around the 8 x 11 room section and paint with rubberized roof paint, so the end of the shipping container should be fairly insulated.

I am thinking the window unit should be a bit more powerful than a unit rated to cool a 100 sq foot room, because this is a shipping container... but it doesn't make sense to go overkill with a unit that's exceedingly too powerful. It's hard for me to determine what's about right...

I have been reading your threads here for a few years and I am definitely interested in your thoughts! :thumbsup:

The interior door has a 2" gap at the bottom, Should l allow it to function as a vent to the rest of the container, so that the Cool air flows through to the uninsulated section, to help keep it cool and dry? I know it won't be 76 degrees, but some cool, dry air would be good, right? Or would that be really inefficient and cause the unit to run endlessly?

I have already installed a solar powered vent on the roof at the end by the double doors, would it make more sense to add a pair of fresh air vents and seal the interior door?

Thanks for your feedback.

 

[EddieWalker]

Do you want to cool the storage area? If not, I would use an exterior door between the living area and the storage area. Then to vent the storage area, I would put my wall vents down low in opposite corners and a ceiling vent in the middle of the room. The idea for a vent it so move the air through the room. They do not cool anything, but the airflow will stop condensation from building up. More vents don't improve this, and sometimes they can hurt the process.

For such a small room, you'll be fine with 5,000 BTU or smaller, depending on how well you insulate it. Remember air getting into the room from the outdoors is worse then not having enough R value in the walls. Ceiling insulation is more important then anything else. Think R30 for the ceiling as a minimum.

Eddie

 

[orezok]

One thing you don't want to do is oversize the unit. Yeah, it will cool down quickly, but the room may not be comfortable because not much humidity has been removed.

A smaller unit that runs more will remove more humidity and result in more comfort.

 

[muddstopper]

Working for the railroad and living in camp cars for years, heat and cooling where always big issues. My advise, since those campcars would be very similar to your storage container, would to get and roof mount RV heating and air unit. Most of them are 120v, self contained, and mounted in the roof out of the way. 2 such units would do a decent job of cooling a 40 ft campcar. By the way, those campcars where just reefer type truck trailers, very poor insulation, outfitted with bunk beds and slept 12 men to a trailer. Osha finally mandated only 8 men per trailer and most railroads no longer use campcars for their traveling gangs. Except for NSCorp who doesnt seem to give a crap about their maintenance forces.

 

[Gary Fowler]

I think Eddie is right, 5000 BTU would cool the whole container IF it is all insulated. Shading from the sun is very good also. I have a 14,000BTU and it cools my whole 950 sq. foot shop with 9 1/2 foot ceilings, but it is well insulated. If you are going to run the unit all the time, I think that the 5000 BTU unit will keep the entire container cooled. The coolest area will be closest to the AC unit so even without a wall and door that end of the area will be cold, but opening up those big doors on the end will let all the cold air out quickly. With a 2" gap under the door, some cold air will filter out to the larger area and somewhat condition the air but don't expect a lot of cool especially with the container not insulated.

 

[Gary Fowler]

You may also want to do a little re-design of your layout to keep the futon from almost completely blocking the interior door. Maybe if you moved the interior door to the opposite side, turned the futon so it is aligned with the bottom wall, the put the desk on the wall next to the exterior door, it would work a bit better. Just play with your design a bit to make it more functional. Maybe even make the room a little larger as a 5K BTU would cool a much larger area than you have planned.

 

[Diamondpilot]

I've never bought a window unit before, so I am researching what I need. I have a 40 ft shipping container, with an 8 x 11 foot section walled off at the end opposite the big doors. I am looking to cool the room section to about 76. It's about 88 square feet. The window units are rated by BTUs and the vendors list suggested room size, such as this one from Lowes. Yeah, that seems like a lot of AC for a small room, right? I intend to add Foam it Green to the exterior walls around the 8 x 11 room section and paint with rubberized roof paint, so the end of the shipping container should be fairly insulated. I am thinking the window unit should be a bit more powerful than a unit rated to cool a 100 sq foot room, because this is a shipping container... but it doesn't make sense to go overkill with a unit that's exceedingly too powerful. It's hard for me to determine what's about right... I have been reading your threads here for a few years and I am definitely interested in your thoughts! :thumbsup: The interior door has a 2" gap at the bottom, Should l allow it to function as a vent to the rest of the container, so that the Cool air flows through to the uninsulated section, to help keep it cool and dry? I know it won't be 76 degrees, but some cool, dry air would be good, right? Or would that be really inefficient and cause the unit to run endlessly? I have already installed a solar powered vent on the roof at the end by the double doors, would it make more sense to add a pair of fresh air vents and seal the interior door? Thanks for your feedback.

I work on boats a lot. House boats are about the same thing as one of these units. I would get a roof top unit from a camper before I got a window unit. It will give you heat and much better circulation in addition to ac. We use these on house boats all the time.

Chris

 

[radioman]

All good points here . :2cents: I'd put unit up high as possible close to ceiling as heat rises and cold sinks. Put ac in shortest width of unit. Also you didnt say where the storage unit is. Is it buried undeground? in direct sunlight? with shade or some? in northest or south? in hot and dry areas like arizona or some desert? 5k would be good for most places but a hot,dry. scorching 100 degree heat in direct sun all day, all month 5 k might not be enough. 12-15 k might be better.

 

[ace10]

Where is this located?

How many degrees of cooling are you looking to achieve at your peak outdoor temp?

Do you have heating requirements?

Will this oven be baking in the sun all day long?

 

[Wa11banger]

To the OP I am not much good for advice on what size or location of A/C unit but I do have two in my 36ft rv and the responses are correct it is good to have heat and cool out of one unit and they are not that much more in cost.. Although slightly more effort to install and maintain a seal on.

However, if you get one of the wooden floor containers do not put living space in it until you have completely removed all of the flooring and replaced with builders flooring or some other substitute. They contain very high levels of harsh chemicals like formaldehyde and wood preservatives containing a number of organochlorine insecticides, including aldrin, dieldrin, chlordane and lindane. All of which are not really healthy to us with regular exposure. Some of these do not have a high vapor-off capability but some do.. Read your container data plate to identify what the floors were treated with and make a good sound decision on if you should replace them or not. I would hate for you to have health issues with your great escape place.

Rick

 

[Stuka]

Thanks for the helpful comments and suggestions, guys!

Sounds like around 5000 btus is the way to go, especially considering the humidity factor and giving the unit time to dry the air. I'm on the Gulf Coast in Texas, about an hour south of Houston, so this summer heat and humidity will play a big role in my decision. I wish I could insulate the whole container but closed cell foam is expen$ive.

I'm looking for 76 degrees on a 100 degree day. It is pretty much uncovered and will get a lot of sunlight. Gary, I am not expecting the overflow from the interior door to do much cooling the storage area of the container, but I'm thinking any dry air that "leaks" by the door will go towards reducing condensation. The big question for now: should I seal off the insulated living space and use an AC that fits 100 sq ft, and use fresh air vents as pictured on one end of the storage section to flow air through to the solar powered roof vent, to keep the temps and humidity in that section comparable to the outside, to avoid condensation...

I'll check into roof AC units, that would be nice and tidy looking.

I have read about shipping container flooring and the pesticides used. I don't have a manufacturer's label but there is no strong odor coming from the floor in my shipping container (which I refer to as my "bunker", easier to say in casual conversation ). I have laid down some vinyl tiles in the section I will be using as living quarters, that should seal off some of any possible vapors.

 

[Gary Fowler]

I think I would try to seal off the storage space completely. A little bit of cold air from under the door might be doing just the opposite of what you want and cause condensation or mold problems especially in the really moist air around Houston just like an iced tea glass "sweating". I would put in some vents at the floor level and again at ceiling height so there is natural circulation sucking in the cool air at the floor and venting hot air out the top. I wouldn't mess with putting anything thru the ceiling due to the corrugated construction of those containers it is very hard to get a good seal on those flat roofs which have to channel the water to the edge and depending on how you set it, it could hold some water on top. I like to set them lower on one side by about 1" so they drain well.

 

[Stuka]

I think you're right, Gary, it makes more sense to seal off the living quarters and use ambient venting on the storage area.

I've modified my floor plan, per your suggestion, may as well use the futon as a sofa and a bed, since that is what it's designed for

 

[EddieWalker]

Why do you need a door to get to the storage area from the living area? Why not just go through the existing doors and not have that door taking up wall space?

Or if you keep the door, why not put a bathroom there?

Eddie

 

[Diamondpilot]

Going from what I know about boats and campers I think 5000 btu ' s is too small for daytime use in you area. You need to double that.

Chris

 

[lutt]

I agree with DP, living in Northeast Arkansas I would want a 14000 btu, I believe that is what's on our 33 ft travel trailer and it's not enough some times! And that's the least I would go with! LUTT

 

[kenmac]

Heat gain inside that all steel container is going to be very high. I don't think you can maintain 76* inside with 100* ambient with that 5 K unit. I would suggest at least 1 ton (12,000 BUT) of cooling

 

[EddieWalker]

How many square feet are you considering when you say he needs more then a 5K unit? I'm thinking that it might be on the big side due to the small size of the room he is wanting to make a living area. But since it's so difficult to insulate a container without building additional walls and a ceiling, I figured to oversize it to make up for minimal insulation.

As for using a ceiling or RV unit, I've never found one that cooled all that well. My experience with RV's is that they are also poorly insulated and you rely more on the dash AC system to keep cool then the roof unit. The ones I've been in also had separate propane heaters near the floor.

The cost of an AC only window unit is just a couple hundred bucks. Add heat to that and it triples. I suggest a window unit and a separate, plug in space heater. I like the tall, ceramic ones, but there are too many out there to say for sure what is the best.

Eddie

 

[murphy1244]

1 ton of a/c to 600 sq ft. 12,000 btu per ton as we were taught.

 

[Industrial Toys]

I'm not sure what you hope to achieve. Cooling or dehumidification? I got a forty foot container a few years back and was really dismayed about the water dripping down from the ceiling when conditions were right. As it was, I built a drive shed and relegated the container to storage of things that should just be out of the sun, away from animals and pine needles. But, my thought at the time was just to install a dehumidifier.