I am a dealer and I have been getting my solar water heaters and PV backups from Techwin. I have worked with Techwin for the past 12 years and I can attest they have been the best brand ever to work with. At first, I had my doubts about supplying their solar water heaters to my clients but fortunately, everything turned out fine and now I can attest that this is the best quality system that has a durability period of 45 years. Go for Techwin and it will help you solve all your backup and solar water heater problems, I can recommend it 100 times. Their solar water heaters are quality and satisfaction is guaranteed. Once you make an order from Techwin they deliver on time, once you have a problem they are always ready to send their technicians on-site, to solve all your problems. All my clients have recommended me to other clients because of the brand and the quality of this solar. Builders and co-creators go for a quality system that has a long durability period like what they provide.