Hi. I'd be grateful for any information/advice anyone can give me.

We live in an older house in a flight path and are looking to replace our windows to aid in noise reduction. I have been doing some research and have a few questions. It looks as though the best measure of sound-blocking performance with regard to aircraft noice would be the OITC (as opposed to the STC). What is a significant (ie noticeable) difference in OITC (1, 5, 10?)? Is there a simple rule of thumb to how much of a decibel reduction is provided by a certain OITC? Finally, any idea what the OITC of old-school single pane aluminum frame windows would be?

Thanks in advance. I'd also appreciate any comments from anyone who has dealt with similar issues.