Idk what the exact differences are. I only know, that newer buildings are already required to have proper insulation, so for those that are built or (properly)

Idk what the exact differences are. I only know, that newer buildings are already required to have proper insulation, so for those that are built or (properly) renovated in, idk maybe the last 20 years or so, should be fine. But we also have plenty of older buildings, that need some work. That's probably also one of the reasons why many people go for wood pellets to replace the gas heater. Add to that all the really old buildings, that can't be renovated due to urban heritage protections. But as said, all the companies are booked out and parts aren't available fast enough, thanks to outsourcing to China...