hi there kesh, give me a buzz regarding the ecodan ashp, ive just installed one in my home in derry,its 2800sq ft, your welcome to come and check it out and ill give u a run through on the system, ill give u an unbeatable price on ecodan, and they need to be teamed up with correct water cylinder with specific coil sizes to work properly, my number is 07846080302 paul