EZ-37 Solar Water Heater Panel by Heliatos

Pros: Affordable cost. Simplicity of operation and, to an extent, installation. Bottom feed feature allows conversion of conventional hot water tank. Good instructions and quality materials. Quick, free shipping with individual components clearly organized and labeled (if you are purchasing one of the packaged systems).Cons: No SRCC (Solar Rating Certification Corporation) rating; therefore not eligible for most federal, state and local government income and property solar tax credits/exemptions. The 2'x 2' panel requires 7xs the panel connections (which could prove vulnerable) and over 2xs lineal feet of a standard 4'x 8'panel. Metal filings left on the inside of panel copper connection pipes.Overall: Five STARS because this product and customer service exceeds expectations. Excellent for preheating hot water (no doubt that payback will be short-term), but could manage as a primary hot water heating source depending on individual HW demands, effective tank insulation, and climate. A 4-panel system, with a 40 gallon HW tank, with a family of two located in the Northeast (Lat. 42 deg.) is adequate to supply domestic hot water needs on most sunny days in warmer months (colder months the system would be drained-down/winterized). You will have to decide whether the trade-off is better to purchase SRCC rated 4'X 8' flat collector or evacuated tubes for solar hot water and designing a system with more sophisticated circulating controls and much less connections and reaping the tax benefits; or, purchase the very reasonably priced Heliatos will the smaller, easy to handle panels with the simplistic, direct PV controlled circulating system (pump's speed runs in direct proportion to the degree of solar radiation), but with the elongated installation, requiring multiple panel interconnections.

These are really nice panels. They are not as hot as the larger 4x8 panels but their light weight modular approach makes them much easier to use.One very vulnerable part of these panels is how the 1/4” serpentine tube is brazed to the 1/2” header pipes. If you accidentally turn that header pipe while tightening the compression fittings you might rip the smaller tube right out of the header. I see they now use push on fittings instead of compression fittings possibly to avoid this problem. The good news is that the panels are very well constructed and it is easy to take them apart to repair if needed. I simply cut the header where the smaller tube connected, added a 1/2” T and put a plug into the T and drilled a 1/4” hole to accept the 1/4” tubing and soldered it together. The fix is stronger than the original.I have 4 of these connected to my electric water heater on the Northern California coast. I have the electric water heater on a timer to come on for an hour in the morning. The panels take over for the rest of the day. If we have a stretch of sunny days the electric heater doesn’t come on at all. We have hotter water than before and our electric bill is lower.I made my own bottom feeder and the one other thing I should add is to be careful if using the one they sell which has a galvanized nipple that replaces your drain valve. My water heater had a solid brass drain valve so the bottom feeder I made used a brass 3/4 nipple not galvanized. I wrote the company asking about their galvanized nipple but they never responded.

Works good