On 5/8/2018 11:02 AM, Jimmy Wilkinson Knife wrote:

The glass doesn't provide the majority of support, the window sill does
and if it can't handle the weight of an A/C unit you have far bigger
problems.* The unit is pretty much balanced there with some force being
taken by the bottom rail in a double hung window.* Nothing major if
properly installed.

I'd still be concerned by vibration.


There are millions of them in use. Problems are rare, usually from
homeowner mistakes.