If you’re so fearful of opening the windows (I basically live /w open windows 6 months out of the year in a NYC apartment that’s closer to other homes than your house), perhaps adding an economizer to the existing system that draws in cooler outside air might be an option.
Or window fans — they’re loud enough to block any sound coming out and non 100% transparent. A ceiling fan is also nice since it mixed cool and hot air from top to bottom.
