Hah, no my house was built in the 1750s or something like that - single glazing on the front and with fairly minimal insulation, plus it has no cavity wall (a mixture of wattle and daub and brick). It is a mid-terrace though so I benefit from neighbours being either side.

There have been a few cold snaps here where the weather has been down to -2 some days, but it’s been fine. I had a couple of minor installation issues (eg 3 way valve set incorrectly) but once those were fixed my house hasn’t dropped below 19C.