Installation of a room a/c in awning window

I need to install a 8k BTU room a/c in an awning window. I know I need to make a shelf that sits on the bottom window sill for the a/c to set on. Any installation hints?

The model is a GE AG-08.

The outside a/c cover measures 14" H x 22" W

The window opening is 20" H x 32" W, which includes the window stop moulding, otherwise the opening is 21" H x 33" W

 

The geometry of the window and unit is too uncertain from the information that you supplied to be specific. The manufacturer's installation guide and kit covers most possibilities.

 

The only instruction in the a/c manual was to contact a professional contractor for any window other than a double hung window.

I've checked 3 home repair guides that I have, plus ran several search queries on the internet, and visited several home repair sites including doityourself.com.

My plan was to make a 4-sided frame out of 2x8 that would fit into the existing awning window frame. The a/c frame would have to be custom-fitted to the window frame by removing wood (router, table saw) on the side that contacts the window frame. This would allow the full weight of the a/c to rest on the a/c frame and window frame without damaging the window stop moulding.

I've seen a/c shelf frames for windows other than double hung but I can't use them without damaging the o/s siding or the i/s moulding/finished walls. One site recommended putting an a/c opening in the wall, but my exterior wall is 10" cinder block (house was built in 1948).

I think I'll go with my original plan. It may take a while but I think it would be best.

 

Minimize damage to the window and frame. Make it sturdy. Make it secure so that an intruder cannot enter through the opening by having fasteners not accessible from the outside.