Thanks for ESP team, especially Michael Wang, who is fully deserved to be given a 5-star medal. He explained all the details of related products to me, gave us some valuable advice and replied to my message always instantly. I will say that is real customer service. Today ESP arrange two boys (Hopa and another one) to install our solar HWS and it just took 2.5 hours all done, very tidy and clear steps from beginning to the end. Totally I will say such good experience with ESP, and strongly recommend these guys...thanks again for your help.