casement windows

i have casements throughout my small rancher. they're about 15 yrs old. when screens came out and i was shutting the windows tight, some won't shut completely. i suspect they may be a bit wonky, but haven't a clue how to adjust them. with winter coming, i'd like not to heat the outdoors thro my semi-shut windows. any ideas ??

 

The first thing I'd suggest is to take on old paint brush and clean out the track on the bottom where the casement slides as it is cranked open. You can lubricate this track with silicone spray once it is clean. Perhaps this will help the window crank shut. If they won't go all the way shut due to the sash "dragging" as it goes closed... there is one trick I know that works for wood windows. That is to raise the sash up as high as you can, and insert a 1/8" shim (I use small plastic shims) inbetween the sash and the hinge hardware (this would be the bottom corner of the window that is facing you when it is cranked open 90 degrees.)

Often, there is enough play in the hardware that you can stick a shim in there and what it does is it raises the window just enough that it won't drag on the opposite side as it closes.

If it's not a wood window, then I guess that idea won't work. Sometimes it's the crank mechanism itself that is stripped and won't close the window that last inch or so.