They are aware that the system design element is extra complicated for heat pumps than they are accustomed to within the gas boiler area. https://uclass.uos.ac.kr/local/ubonline/view.php?id=3026&returnurl=aHR0cHM6Ly9pbnRlbnNlZGViYXRlLmNvbS8/bW9kPXNwYWNlJnVpZD0yODA2NjY1