The window treatment option might be worthy of an investment.
I live in northeast Florida. In a house that is 80+ years old, and of the 23 windows, 6 are the original (leaky) counter-weighted standard windows (and most of those were painted-shut 20+ years ago).
About 5 years ago, I had cellular window shades installed in 20 of the 23 windows. The cellular shades provide fabric-enclosed horizontal cells, which act as insulation against solar heat. For those that arent blackout design (allowing NO light or heat through the fabric, ideal for bedrooms), I get good ambient light, without the heat and bleaching effects. Havent measured the difference in electricity costs before/after, but the comfort level is markedly improved (over the vinyl shades). And the lowering/raising of the shades is as easy as pulling a string.
Those facing heat wave conditions in the Midwest and along the East Coast have my empathy. But I would encourage everyone to consider looking at long-term solutions. Global climate change is upon us. It aint going away, at least not anytime soon. A few dollars spent now may save hundreds or more as we swelter through the foreseeable future.