Mineral Wool (Roxul) vs. Kaowool for smoke shelf cavity

[glenlloyd]

I actually did replace all of my windows, fully knowing the minimal benefit of the improved "R" value. But the drafts with the leaky old gaskets were horrible, requiring wearing a coat while typing on the computer I am presently using located next to a window. The new window no longer required the coat - it was amazing, and it was colder last winter. So I think if the window seals responsible for preventing draft are good, don't waste money on new windows unless the old ones are single pane.

As a solution to drafts new windows are a good thing, but if your windows aren't drafty and you're looking for increased thermal efficiency they're a really bad idea. My windows are very old but they aren't drafty so new windows would be a waste.

steve

 

[fire_man]

The only other thing I can add is an interesting measurement I took. Last year I replaced half of my 1985 Rivco windows with Marvin Wood-Ultrex windows. When it was extremely cold out, (<20 degrees F) I measured the glass temperature of my old and new windows using an IR gun reflecting off black tape adhered to the center of the glass. In every case, there was a 6 degree warmer reading on EVERY new window with respect to old windows. That likely cut down on convection currents circulating in the house which definitely made the house left drafty. Six degrees warmer on all that glass area had to add up. Combined with the better seals, the house was noticeably easier to heat with my FV and more comfortable. I agree new windows won't pay for themselves the way many window makers claim, but there are other factors to consider.