On Feb 22, 4:08 pm, "Buck Turgidson" wrote:
Yes, you're giving up a lot. When your original windows were installed, it
is possible, even likely given that your house is 60 years old, that they
did not insulate between the window frame and house framing. Significant
energy loss occurs there. Just replacing the sash won't correct that.

Tear them out down to the frame and do it right.

Any decent replacement window installers will insulate this gap and
any voids you have. Even Lowes does it.

- Jeff