ASHP are claimed to get more healthy than fossil-fuelled heating for example gas heaters by maintaining a far more even temperature and steering clear of destructive fumes chance. Air source heat pumps use exactly the same style of technologies that keeps a fridge or freezer interesting – but in reverse. https://purethermal.co.uk/media-news/q4-launch-lithium-large-capacity-r290-ashp-from-pure-thermal-and-enerblue/