I get you OP
Most houses were built with a fireplace and chimney. So if fire was lit, that room would be warmer than other rooms.
Not everyone could necessarily use their fire though, e.g too expensive to get fuel, dodgy chimneys etc, but it was still there and an option, albeit maybe not feasible for some people.
It is wrong to say every house had some heat... because they didn't. I'd have guessed most houses would have lit a fire, or had a plug in fire or something, but as demonstrated above lots of people didn't have access to it, for whatever reason.
So I think that insisting people are wrong about that is derailing your point, which I agree is important
Today, if your house is dependent on gas/electricity for heating, and so you don't have option to e.g. light a fire... it won't be the same as houses that had/have no central heating as most of them traditionally would have had some sort of "burner" in at least one room.
And while the rest of the rooms in those houses could be absolutely freezing, there was at least some heat, somewhere, which contributed to keeping damp out and warming the house a bit.
If people have to avoid turning on their heat at all this winter, houses will eventually start getting damp and they could have problems with pipes freezing etc. Outside will start feeling warmer than in
And it is a disaster that people have to live like that in 2022