Ok first I advise you to get out your lease and read it carefully. Make sure there is no language in it claiming you are responsible for such problems. Now even if it does state that I tend to say you are still not responsible.You should definatley call a local landlord tenant attorney and speak with them. It sounds as if your landlord is attempting to take advantage of you and that is not right. As for insurance that should not be an issue because whether he has or does not have insurance plays no part on whether you would be responsible.When you rent an apartment as a tenant the way a normal relationship goes is that you are responsible for the everyday upkeep and ensuring nothing gets damaged (this is why there are security deposits) you are not responsible for major issues such as a heating system. That is part of the house itself and as a renter not your responsibility.Call a local attorney with a little pressure the landlord should back off realizing they cannot get away with this