The plastic window kits work well, but only the good stuff (3M, for example) lasts very long. I use it on some hidden north-facing windows that aren't opened in the summer, and it lasts 2-3 years before it gets brittle and falls apart in the wind.
I've had good luck with rope calk, but again, only the good stuff. The cheap stuff cracks and doesn't hold. Using rope caulk that isn't fresh never works either.
A caulk gun and latex caulk is what you want for any permanent holes, like gaps around window frames or non-opening windows. I find the latex easier to remove than silicone, and it can be painted.
When tracking down every little leak, at some point the cost of all that crap is more expensive than the savings. Depending on where you live of course.
If your house has a humidity problem, it might actually be in your best interest to
not seal the place up like the International Space Station.
Don't use the shower or bath without the exhaust fan on. Ditto stovetop cooking. Especially if it's a small house, apartment, or trailer.
The window's aren't that old but the building is it's settled over the years a lot causing this problem.
Tell me about it. Our house, a three story Victorian, was built before 1900. We've learned to accept that the house 'breathes' and 'circulates' and sometimes becomes physically restless. We've also learned to appreciate the genius of the builders who strategically placed the hot water radiators beneath each window. :thumbup:
