The 18 tubes you mentioned should be 58*1800. If it is this model, the merchant's selling price should not exceed 1,600 yuan, including installation and material fees.

But I would like to advise you that 99% of manufacturers with registered trademarks similar to "Peking University" and "Tsinghua" are just passing by colleges and universities, that is, the trademarks are not registered at all. Whether the quality is good or not depends on your luck. . Among them, I know that only the "Tsinghua Sunshine" trademark is a registered trademark, but at this year's solar water heater industry summit, it is very likely that the "Tsinghua Sunshine" trademark will no longer be used in the second half of the year.

Due to the relatively low production and technical thresholds and weak supervision, our industry has a serious mixture of good and bad. In the past few years, the phenomenon of playing Beijing brands and universities on the sidelines is actually mostly related to universities. It doesn't matter at all. In recent years, there has been a trend of marginalizing electrical appliance brands, such as "Haier Sunshine", "Gree Sunshine" and "Midea Sunshine". In fact, they have nothing to do with other big companies. They may be sold in your own yard. Here, the couple plus the seventh and eighth aunts gave birth. The ones that are also used under the banners of "Hong Kong Four Seasons Muge" and "International Emperor Ming" are all fake.

As for the website, there is no authoritative one. You can only check the brands one by one.

The key components of the solar water heater are the insulation of the water tank, the material and thickness of the liner steel, and the quality of the vacuum tube. However, even those in our industry cannot use these things without damaging the product or using precision. The instrument cannot be identified, but once it is damaged due to substandard quality, it cannot be repaired. For example, if the liner of the water tank leaks, you must find the leak point, completely destroy the end cap at one end of the water tank, dig out the insulation layer, weld it with argon arc welding, re-foam it with polyurethane, and then find a new end cap to fasten it on. After all the trouble, the cost is about the same as buying a new water tank, and the welding joint will not last long.

So, I advise you to spend a little more money and buy a branded one.

I would like to recommend a few to you. The quality ranges from good to slightly worse, but they are all suitable for daily use. Tsinghua Sunshine, Huangming, Temple, Linorite, Yicanon, Four Seasons Muge, Taiyangyu, Sangle, Sangxia, Meiling, Royalstar, etc., of course there are some that I can’t remember. Depending on the model you want, the prices of these brands should be above 2,800 yuan