Radio Man wrote:
Underfloor Heating is wonderful to live with but bloody expensive to run a
friend has it but dreads the bills. We visited when they first moved in and
it was glorious but next time we needed thermal underwear and were given
blankets in the sitting room after the first bill.

UFH is just a big radiator. Like any radiator, it's up to you what you
connect it to.

Electric UFH is just a big electric resistance heater, and unsurprisingly
that costs to run. Wet UFH can be hooked up to a boiler or heat pump - the
latter can run more efficiently due to a lower flow temperature.

With any UFH, if somebody installs it with no insulation underneath you're
heating the ground not the floor. That's a faulty installation.

Assuming minimal losses to the ground, the heat flux from wet UFH should be the
same as radiators and so the efficiency roughly the same.

(although I don't know how the boiler copes with a mixed UFH/radiator system
- I assume the UFH isn't going to run at radiator temperatures? Is there a
thermostatic mixer?)

Theo