My shop does not have central air and does not have operable windows. There is a steel door in the back and cinderblock walls. My landlord is against me cutting a venting hole in either the steel door or the wall...any wonderful ideas, anyone, for how I can use a portable air conditioner here...it was murder here last summer!!!

  • No windows, cinderblock and a steel door. Sounds like a prison. If you can't cut a hole in the wall, the door or the roof, how do you plan to do air handling? By teleportation? Mar 17, 2015 at 0:56
  • 5
    Look for a new space to rent with a more reasonable landlord, or operable windows. Or sign up to have a few tons of ice delivered every few days, if you at least have a floor drain.
    – Ecnerwal
    Mar 17, 2015 at 2:35
  • I wonder if this thread has the answer that you are looking for is in the thead: portable air conditioner exhaust diy.stackexchange.com/questions/90058/… May 5, 2016 at 20:57

6 Answers 6


Do you have a budget in mind for adding the ac? You can use a water-cooled unit, but plan to spend $1500 and up. These units can be hooked up to a water supply (sink, garden hose, etc.) and drained back to a sink, outside, or wherever is available.

The heat from the air is transferred to the water - much like a geothermal ac or heat pump works. We use these a lot in restaurant food storage rooms and for portable ac's at public events.

The so-called vent-less ac units work by dripping cool water over a screen in front of a fan. The humidity becomes unbearable and people will feel very uncomfortable quickly. Avoid these systems entirely.


If the steel door is of a standard size, see what it would cost to buy another door of the same size. Then ask the landlord if you can replace it with your own door, and cut a hole in that.

In the optimal case this would just require lifting the old door off the hinges and the new door in its place. At most you have to unscrew the hinges and move the lock from one door to another.

  • This is a great idea. Actually, why not just price the door and offer to pay the landlord for it. Then cut the hole in the door that's already hanging there. Or buy an identical or equivalent replacement door and keep it in a corner of the shop, or give it to the landlord for storage (and cut the hole in the door that's already hanging there). Hanging a new door would be easy, though, either way. Mar 19, 2015 at 19:22

I'll bet you can take a piece of OSB, cut it just smaller than the jamb of the door, put some pipe insulation around it, and make a press-to-fit door. Cut a vent in the middle, hook up the AC hose and you're done. It will only work when you are there.

Idea 2 - move involved. Open the door so there is a gap of about 8". Now build a frame around the door as it is open; you will probably need to wrap both the top and the bottom to make the frame work. Vent through the jamb.


There are ventless portable a/c units. they are typically in the 5,000 BTU range. They have a container that holds the moisture that is removed from the air which you must empty manually. In very high humidity areas it can become full in as little as a few hours. As you can imagine they are not particularly efficient as the heat it generates is contained in the room. They work best for small rooms like an office or bedroom.

  • 6
    Sounds more like a dehumidifier than an A/C unit to me.
    – Tester101
    Mar 17, 2015 at 2:26

Land lord said nothing about a hole in the roof :)

Roof Vent

Roof vents are -really- easy to install, and look great when done properly! The directions on the box will tell you everything you need to do, but really it really is just as simple as cutting a hole in the roof, caulking, and tucking under a few shingles!

If they don't go for a roof vent, you could use an under-eave vent depending on how the structure is designed.

Under Eave Vent



Check out that link i think you all will like it the design is funky af but hey it's a really a/c and you don't need to vent the exhaust yup no vent house mind you they make these all different price is around the same $237 - $500

Let me know what ya think.


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