The biggest single COL factor for middle class folks is housing. It can vary dramatically within a state (and usually does), but a state’s median home price is a good indicator. Texas is low, but 27 states are lower.
The most expensive and affordable states to buy a house, ranked (https://www.businessinsider.com/cost-to-buy-a-house-in-every-state-ranked-2018-8#24-minnesota-28)
To compare states’ overall COL, I use the “Missouri” COL index. I think it makes a more realistic comparison than the BLS figures. Using this index, Texas is low, but 17 states are lower.
Cost of Living Annual Average 2018 (https://www.missourieconomy.org/indicators/cost_of_living/)
Looking at this index, it’s clear that the “red” states are cheaper to live in than the “blue” states — by a LOT. For instance, for the first quarter of 2019, California’s COL is an astonishing 65.8% higher than Texas.
Finally, you have to factor in your earning power in each state (assuming you are still working). Generally you’ll make more in blue states, but not enough to offset the higher COL.
For instance, looking at 2017 “median household income,” California is higher than Texas — $71,085 vs. $57,206. CA averages 25.5% higher income.
List of U.S. states and territories by income – Wikipedia (https://en.wikipedia.org/wiki/List_of_U.S._states_and_territories_by_income)
But after factoring in the respective state’s COL (including taxes), you’ll live significantly better economically in Texas. Remember, CA’s COL is 65.8% higher than Texas.
My favorite state? Tennessee — especially eastern Tennessee — from Nashville to Knoxville. Low taxes, booming economy, and not likely to “flip blue” anytime soon — unlike Texas.