Window Guards

How about a stop in the channel on either side above the lower sash?

http://www.decorartsnow.com/decorartsnow/wp-content/uploads/2013/11/1258714.jpg

Measure the distance between the head and the top rail of the lower sash (when closed), cut a piece of aluminum (or wood, or whatever blends in) that is 4.5" shorter than that distance, and fasten said piece on each side of the channel with the top of the piece butted against the head of the window.

That will limit the lower sash to opening 4.5 inches. Shouldn't require any sort of heavy-duty fasteners either, just a couple of small screws in each stop.

flarf,

I thought of that. Does anyone know of an aluminum shop who can make a small curved piece of aluminum? I will need 40 of them for all the windows.

Why curved?

I think placing it inside the channel will disrupt the function of the balancer that is within the channel. Plus it has to stick out from the channel in order to block the sash. That would essentially be the same as the L-shaped bracket.

A curved piece could be installed just outside the channel with a screw.

I want to open my windows all the way and would like to have horizontal bars that are custom fit. I do not want the expandable version, which takes up a lot of your view. Any ideas who would do this?

The guard needs to be approved by the city: http://www.nyc.gov/html/doh/downloads/pdf/win/window-guard-board-list.pdf