Mike4 wrote:I'm told that in countries like Canada, Norway etc heat pumps are far more widely used than here but I've yet to find out if these counties are running water-filled radiators with them, or ducted warm air heating systems. Does anyone here know perhaps, please?
In the northern US and Southern Canada ducted warm air systems or splits are far more common, hot water systems are typically high-end exotica. There are many reasons, but a big one is that in most of the area there is a significant cooling season and a water filled radiator is a poor air conditioner. This also means there was a pool of A/C technicians who already know most of the installation and maintenance. There is also a supply chain of behind them.
The UK should probably be importing Spanish plumbers and using mini-splits to replace radiators. Many if not most UK radiator systems were already a retrofit. Retrofitting a retrofit is a kludge too far. A similar mistake is being made with retrofitting the boiler industry. Selling and servicing heating systems is not a hereditary right. Too much effort is being spent prodding enterprises to change and not enough on new entrants. Some of the old ones will adapt, but many should be replaced.