I buy it for my home an 1 year of working is good we well maintained that but due to some fault conditions in the board it working is not good they took an service it says for every one year you should change the exhaust sytem clean for the proper works they charged it 500 for to clean up the exhaust system for every year the same conditions should took place they use it for the copper coil used in the windings for cost it conductive is good but its timing saving and consumption of energy is good if not in fault systems