I was lucky enough to have lived most of my childhood in a Georgian farmhouse. It was built around 1820. It also had a huge range, dating from about 1880 so not quite original, which my grandma used to light whenever we had a power cut. The heat that came out of the range used to keep the kitchen roasting hot, and it heated the rest of the house via the huge chimneys which went through every room. Not as good as central heating, by a long way, but certainly kept the edge off the temperatures, and by wearing a couple of jumpers you were fine.

Also, lighting fires in the rooms do produce a lot of heat.

The house had very thick walls, which retained heat in winter, and kept it cool in summer.

In case anyone is interested, I have found a picture of a range very similar to the one we had. See link.