Have you checked if the sash itself is loose or rattling around? Sometimes tightening up the sash locks or adding a bit of weatherstripping along the ...

I totally get the hesitation around silicone, but honestly, it's not always the villain here. I've used it plenty of times without issues—key is prep ...

I've been thinking about acrylic inserts myself, but haven't gotten around to samples yet. Do you know if they come in different thicknesses? I'm wond...