We were using them in our old home
you need a boiler, pipes, some sort of small electric motor (for water distribution often built with the boiler) and radiators, plus doors and windows should remain closed all the time to maintain the temperature, it normally takes 2 days to warmup the whole house, and our gas bill was used to be extremely high due to the boiler (new boilers are better but it will cost you very much) ideally the house should be carpeted wall to wall to increase effiecintly of central heating. I also used to put my towel, cloths on radiator to keep them warm.
Based on Pakistani culture and attitude towards winters Central heating are no substitute of gas heaters, yet they are safe as compared to gas heater you can keep the radiators on 24x7 without any fear of carbon monoxide gas, they keep out winter dryness. Yet poor installation can cause serious damag to your home..and of course they are expensive and running/maintaince is also expensive....other options can be buy a genuine exhaust free japanese rinnai gas heater and use it the way you like.