Ductless mini split in apartment building

You would need to hang the condenser outside the building on the wall as believe it needs two sided ventilation. Perhaps you can figure out a way to place the split unit condenser perpendicular to your window and supported by brackets which mount like normal air conditioners (essentially not on building exterior wall). Most buildings don’t allow hanging condensers on the exterior walls. However, there are through wall condensers with ducted air blowers.

That's helpful thanks. I was thinking that we'd need to use mounts/brackets to place the condensers, which would make one of our windows useless really, but the benefit of not having window units anymore would be well worth it.

If the wall you're considering mounting it on is on the property line, it may be a no go, unless your building owns the air rights to the adjacent property.

We have a mini-split but the condenser unit is installed on a terrace. I’m not sure you could mount the condenser of a mini-split system in a window but you could probably have a mech eng design you a system that will work as you’re saying. Mini splits are designed for very specific site scenarios. If you want a mini you’re best off mounting in on the exterior wall as others have said. Access is difficult in that situation, though.

Here is a commonly used unit venting through a window (usually gets approved by NYC buildings) but it needs blower and ducts.

https://www.nationalcomfortproducts.com/thru-the-wall-splits

Thanks for the link to the through-the-wall option. Great feedback. I'm hoping that we can install a rack that we can affix the condenser unit to out of one of the rear facing windows and funnel everything in though that window for the rest of our apartment. Through-the-wall vented out a window is a solid alternative if we can make the space for it, which I think we can, since we'd be able to remove the radiators that we wouldn't want anymore.

Can you do a through-wall ? is it allowed ?