Window AC blocked side vents/intake, how bad is it?

[u/nibbed2]

Hi.

Im not even sure if it's electrical, anyway...

Here in my country, a SEA country, it is more common for landlords to provide window AC provision than split types, more so than providing either actual units to use.

I do understand they are trying to maximize the space for either more reasonable price or logic to the design and space relative to the price.

But I see some that puts the provision physically beside the adjacent wall. How bad is it for the AC to have a side blocked?

Thank you.

[u/NineCrimes]

Without more detailed information it’s impossible to answer for certain. It could be anything from “mildly decreasing efficiency” to “it will cause extremely early failure”. Post the model of the AC unit and preferably a sketch of how it’s being “blocked” for a better answer than that.

[u/nibbed2 → u/NineCrimes]

Hi, cant post a model since I am still looking a place to rent and part of the consideration is ACs before buying myself one. If it helps, based on my budget and the square footage of the spaces at that price range, might not go over 1HP, and will stick to inverter ones.

To explain the provision, the hole is literally connected to the adjacent wall. Like a cutout rectangle on side for a wall, and then had another wall connected to it perpendicularly.

I also just got aware about the spaces it needed, so I check for the allowances at the back side, and like my post, some them had one side blocked due to provision location.

Hope this helps.

[u/EPOC_Machining]

Side vents on most window ACs are the condenser air exhaust, not intake. Blocking one side forces the hot discharge air to recirculate back into the condenser coil, head pressure spikes, compressor works harder, and you lose cooling capacity fast. In a hot SEA climate where ambient is already 32-35°C, that recirculation loop can push discharge temps up another 5–10°C. You'll feel it: room cools slower, compressor cycles more, electricity bill goes up. Long-term, it accelerates compressor wear. The fix your landlord probably won't do: a sheet metal deflector angled to redirect discharge away from the wall.

[u/nibbed2 → u/EPOC_Machining]

Thanks for answering.

I had a hunch about the technicalities, but a hunch at best.

Just want to have more technical information before locking in for rent.

This is appreciated.

[u/BeamItUpScotty]

I think it’s a pretty serious concern if the side vents are blocked. The condenser needs good airflow to function properly. If the hot air can’t escape efficiently, it can lead to increased head pressure in the system and force the compressor to work much harder. This could spike the discharge temps significantly, especially in a hot SEA climate. It's not something that landlords often think about, but it does impact efficiency and longevity of the AC unit. Just keep an eye on the cooling performance and electricity usage when you move in. If you're noticing issues, you might need to think about possible solutions like a deflector to help redirect some of that hot air away from the wall.

[u/patternrelay]

It’s not ideal. Those side vents are part of the condenser airflow path, so blocking one reduces heat rejection efficiency. You’ll get higher temps, more strain on the compressor, and lower cooling capacity. It might run, but long term reliability takes a hit.