There can be many reasons (house not being yours, etc.) but one of them could easily be cultural inertia.
During the first half of my life, very few people in my country (Italy) had AC in their homes. It wasn't until the recent high temperatures, which only became obvious 20 years ago or such, that everybody started installing them.
I can't find a historic chart specific to my country, but I suppose it wouldn't be too dissimilar from this:
Probably rental home. I have also been in this situation where my landlord wasn't in the moods of having to deal with AC installation, so he didn't approve it. I can imagine doing the same if I had a Tesla 3 back then.
If you're in the US, you don't need to worry about landlords to install AC; as long as the room has a window, you just buy a window AC unit and stick it in.
Why would they have such a restriction? It doesn't make any permanent changes to the house at all. Will the landlord even see it? You can put it in a window in the back, and take it out if the landlord ever comes by.
Not sure about the parent post, but my lease also has a similar restriction. In my case, it's just re-asserting a restriction passed through via an HOA covenant[1].
But I'd also restrict it as a landlord. An improperly installed window unit can easily lead to water damage through improper sealing or installation, can stress the window frame if it isn't braced appropriately, and be a major falling hazard if installed on upper floors.
Not that it takes advanced skills to avoid most of those potential problems. But there's a reason many apartment complexes nowadays deadbolt utility closets and require maintenance calls for something as mundane as periodically changing out air filters[2]. Making any presumption about the sensibility and competencies of your tenants is a recipe for costly disasters.
[2] For those less familiar with HVAC units, there are one or more air intakes somewhere in the house. Inside the air intake is a filter that traps dust and other particulates so they don't recirculate through the house. These filters get clogged up over time and need changed out every 1-3 months.
>Not sure about the parent post, but my lease also has a similar restriction. In my case, it's just re-asserting a restriction passed through via an HOA covenant.
I have a hard time believing there's any place in America where there's houses in HOAs which don't have air conditioning. Sure, there's houses without A/C in America, but they're always very old houses that predate the invention of the HOA, and usually also the invention of the subdivision. If your house already has HVAC, then this discussion is moot since you'd have little reason to install a window unit.
What about rooms with casement windows? In that case, it will often involve building an adapter to install a room AC. Additionally, landlords could easily be upset by that, since then the window will be extended all the time, allowing it to be caught by winds or for water to damage the frame. There are also people who live in high-rises with windows that do not open.
Or get a portable unit and vent the exhaust out a window or door (or if nfg, into the attic/plenum space). Portables tend to be more expensive, and you usually have a water tank to dump occasionally (condensate), but they are easier to set up, and to store during cooler periods.
What's wrong with purchasing an AC at home?