How can I muffle street noise increase from triple-pane windows?

Question

We recently had new triple-pane Soft-Lite vinyl windows put in around our house, to replace the older single pane, double hung sash windows that were in place before. The odd thing is that the house is noticably more noisy now, we live 2 houses away from a semi-major roadway, it's not busy all the time but does get a fair amount of truck-traffic. I don't get why the triple-pane windows would increase the noise this much, we bought the house because of its convenience to the road but it was really quiet originally. Doing some spot checks with a Decible-meter we found the levels had gone up but when discussing this with the installers they didn't really have an answer.

Would there be a cause for this due to either the window boxes being removed and the current windows being slightly smaller? I am thinking the frames may not be that soundproof and we are getting noise through those. Or perhaps the insulation around the new window boxes is not sufficient. Maybe losing the storm windows has lessened the sound proofing, still triple pane argon gas windows should not increase the noise levels - at least I would guess not. While its nice to be more energy efficient, I don't want that to be dampened by increase traffic noise.

Answer 1

Single glazing with storm windows absorbs sound reasonably well, I would not expect a huge decrease in sound level with triple glazing, but certainly not an increase. Single glazing alone is another story, it's sound absorption is terrible.

The increased sound is certainly due to the frames and adjacent construction. While there is often a correlation between thermal loss and sound transmission, sound is much trickier to manage well. It is sometimes counter intuitive. The construction joints must be carefully detailed. The general concept is to avoid any solid connection between inner and outer surfaces. Any connections should be via resilient, absorbent materials. Typically, you want to fill any voids with sound insulation, though in some cases this has been worse than a simple air gap.

Also consider exterior sound attenuators. Walls, fences, trellises, large shrubs, trees, berms all will help attenuate sound, but when you consider cost vs. benefits, such measures need to be carefully considered.