ASHP are claimed being more healthy than fossil-fuelled heating like gasoline heaters by protecting a far more even temperature and staying away from unsafe fumes hazard. Applying electrical energy, the pump compresses the liquid to enhance its temperature. It then condenses back into a liquid to launch its stored heat. https://purethermal.co.uk/media-news/q4-launch-lithium-large-capacity-r290-ashp-from-pure-thermal-and-enerblue/