I'm going to replace some rotten windows in my house this summer. The ones I've looked at are over $100 and the r-value is only something like .5. I was wondering why I couldn't just make some simple non-opening windows that would be just as efficient.I could make a simple 4 layer window in the thickness space available by cutting grooves into a wooden frame. I could also drill holes through the frame between the panes to allow filling the space with argon or some other gas and then either plug the hole with a screw or a dowl. Does this make any sense or am I wasting my time?