Through the wall AC question

[Tumbulu]

I have lived my adult life in really hot places. And took great pride in only using a swamp cooler for decades for cooling. About ten years ago I started trying more efficient AC’s meant for windows. But in my rather small farm house, rather then mess up the window’s the builder who does lots of odd jobs around here cut a hole in the wall, put a sleeve in, build a platforms for the little window AC and then when the swamp cooler was not enough, there was one small room that was cooler. The power bill went up $10/ month, because I did not use it often.

Then when the swamp cooler’s pump motor and fan broke, there were even more efficient window AC’s and I decided to put another one in, in another room. Did the same sleeve new windowless window installation. Fast forward to now. I found an inverter AC unit that uses 25% less energy. I would like to replace one of these old window AC’s. But in CAPITAL LETTERS it says DO NOT INSTALL IN WALLS OR THROUGH WALLS.

Does anyone know what this is about? I have a friend who is an architect. We went over all the possible differences between a window and an sleeved opening in a wall. All were covered by what this builder built to hold the window AC’s.

Any ideas what the risk could be? What is the difference between a constructed windowless opening in a wall and an actual window?

[Phoenix61]

1. The window closing on top of the unit keeps

it from falling out of the building. Since all the weight is there it can’t fall into the room. My guess is they don’t want the liability of someone trying to install it in a wall, screwing up, and it falling on someone. As long as the fins are outside I don’t see what the problem would be. There’s several DIY You-Tube videos

[Tumbulu]

8. Thanks, that could be it

It is just so weird to see the capital letters thing.

[Phoenix61]

9. Think about all the people who voted for TFG and still think

the election was stolen.

[Tumbulu]

10. Very good point!

Or perhaps I should use all capital letters!

Thanks for the good laugh!

[dutch777]

2. Could be heat rejection or air flow through the unit for motor cooling...call the manufacturer

and ask. It may be that they got the unit a UL listing or some other safety testing and they simply never tested if for thru wall use and they can't certify its safety in that application so the legal department required that note be added for liability protection.

[Tumbulu]

7. I tried that, and got nowhere

Hence calling my architect friend and looking online.

Thanks for the good explanation.

[mn9driver]

3. It probably has to do with how the unit is vented.

Window units often have vents on both the sides and the rear of the unit. If so, they need to be modified if installed through a wall.

In a wall installation, those side vents would be blocked and the result might be a dangerous heat buildup inside the unit. The good news is that other than the venting, window and wall units are essentially the same.

It should be possible to find a unit that has all the features you want that is also safe to install through the wall.

[Tumbulu]

6. The side vents will not be blocked in this circumstance, but I can see

how it would be a big problem.

Thank you!

[Effete Snob]

4. Side vents

https://hvacseer.com/can-you-install-window-air-conditioner-through-wall/

Yes, you can install a window air conditioner through a wall so long as the wall does not cover the unit's side vents.

https://homeinspectioninsider.com/window-air-conditioners-installed-through-wall/

Having said this, you will need to make several adjustments to your window air conditioner before installing it through a wall. Installing a window AC through a wall is dangerous unless you make the proper modifications.

...

A window air conditioner that vents out of the sides and back of the unit are a fire hazard when installed through the wall. Side vents on a through-the-wall air conditioner would produce intense heat that could overheat the system or be a fire hazard.

[Tumbulu]

5. Thanks, yes, all the side vents are not blocked

But I sure can see why this could be an issue.

I appreciate all this help!

[hunter]

11. Other than side vents, another issue is condensate drainage.

You don't want condensate flowing down the inside of the wall, causing the wall to rot, attracting carpenter ants, etc.. Ultimately this can destroy a wall.

If a window air conditioner is mounted correctly in a window the condensate will flow out the back. If water leaks onto the window sill it's obvious.

There's less assurance leaks and overflow will be detected if the air conditioner is poorly mounted in a hole in the wall. You might not see any condensate leaking into the wall.

[Tumbulu]

12. Thank you

Makes sense.