I bought Kaltech Energy Solar Water Heater 7 months back. Its working just amazed me, as they guarantees it even works in rainy days.
My house is at ezhupunna our only water source is well water. 2 months back due to some contamination in water the efficiency of Water Heater felt low.
When I reported the same to them the next day their technician checked and clean water heater tubes without any charges.