Even with an AC, I welcome the coolness. Electric bills are no joke in the summer.
They often go on clearance soon- check home stores as fall sets in. We got a snow blower after Christmas one year for 1/4 the normal sticker price.
My car doesn’t have insulation either but the AC absolutely makes a difference. Maybe your AC unit isn’t working - 40 years is a long time for a unit, may need cleaning or recharging, or just replacing.
Come to think of it, the house I grew up in didn’t have insulation either, and we’d have died with window AC units in the summer.
There is no AC in the truck, and I live in Texas. Definitely can’t wait for winter (that’s the only time it’s cold)
I’m like that right now waiting for the Winter heat to leave
You should get an air conditioner. Even just a little window unit, so there’s one room of your home that’s tolerable.