Only you know the actual cost/benefit of a fix.
Not knowing whether you're near Miami, or Bismarck, it's easy to
suggest that you carefully fit, _and_seal_, the highest R-value
insulation you can find. On _both_ the hot and cold runs. Done right,
you only have to do it once.
Depending on where you are, and the other consequences of humid
basement, you may want to put effort into ventilating bsmt also.
Including blocking moisture entry.