The tubes of all solar water heaters are evacuated. The biggest disadvantage of solar water heaters is that they are easy to freeze when the temperature exceeds minus 9 degrees in winter. I bought 24 tubes and an extended tube with electric heating function. The one I use at home is a 12 year old Aucma. If you are renovating a new house, you must design it in advance. My house uses two water heaters. One is solar and the other gas. Use solar in summer and gas when it's cold in winter. Jinan is cold in winter, you should find out for yourself. Water heaters can be bought everywhere on the street, just type them on the Internet and they will come out.
If you want to buy a big brand, like Linorite Solar, relatively famous in Jinan, I consider that after-sales service is pretty good, the quality is also good, and it is for home use. That's all, because I bought it several years ago,and now there is a new, new technology, which is much better than the one I'm using. now it's enough for a family of three. There are also Huangming brand and Sanle brand. I want to buy the ones that everyone knows. For large manufacturers, you can go to appliance stores like Gome and Suning. They also have buying guides. If you don't understand, you can consult them. First, they are trustworthy and you can complain if you have any problems. Second, you can also participate in events held in the mall, which is more affordable.