After purchasing and having installed a new water heater the first year of use the tankless water coils burst due to cold weather. Water then leaked onto the control board. Bosch claims the warrenty does not apply not even for the board due to feeezing. I was told by Bosch and so was the company that I had install the unit they have had hundreds of complaints of this nature.It would seem that a company that sells a product with a known fault due to poor design should be responsable. I have checked others brands and they have been designed to prevent this problem. If a product cannot be used in a certain part of the country it should not be sold there or the least a warning should be given. Living only on social security wasting $1700 on a water system that is not right having a known defect due to poor design because we have cold here really hurts.