Any question answered...

This is Britain. we have boilers and radiators and inadequate insulation.
I really wish I had proper filtered air HVAC.
Average dual fuel bill is set to become £1300 per annum average.
Anyone who regularly leaves the house with the boiler on is in for a shock.

We also have the all of the above here in Canada, there's quite a range of heating/cooling options. I personally prefer radiant heat, but forced air is what we were saddled with when we bought the place.
We pay a little less than that ^ annually *, but are in a 700 square foot bungalow.

*this includes gas and electricity.