We purchased a Viessmann 100-W heat pump because the company had a good reputation for service. So far we have been sorely disappointed. The unit was installed months ago, by a partner company called Energy Solutions here in Prague. We puchased the most expensive warrant for 10 years. A technician was supposed to contact us to explain how the unit works and do some fine tunning. It never happened. Two weekends ago, the unit stopped producing hot water. With no indication of a malfunction. We spent a weekend with cold water. On Monday, a nice person from Viessmann came. It was the technician who supposed to the final installation months ago. So he did that and tried to fix the problem even if he was not from the same part of the company. After four hours the machine was working again but he did not tell us what was wrong. The following Friday, the machine failed again. We call the same person, but he was on vaccation, and said that we should call the help line. We called Friday evening. We called Saturday Morning We called Saturday Lunch We called Sunday Morning We called Sunday Evening We called Monday Morning No one answered. We called the general number, the person there said to e-mail. We emailed. We called again, the lady said we will call you back and solve it today. Nothing. We received an email to schedule an appointment four days later. We called again, they said email. We called again, they said we were about to call you. Which was patently false as were calling 1 minute after closing time. They said we will solve it soon. As I write still no hot water. I can understand that sometimes a company has trouble. But I dislike communication that is not honest with the customer. I will post this widely and update as things progress.