what can I do? house HVAC broken, ordered a new one $8K.now

Now renter said he is without heat for 18 days. He will deduct 18 day rent for this month's rent.  Do you think it is reasonable?  I am also afraid he will tell to other tenants and other tenants will follow his footstep.  He likes to talk around.  Any good idea how to deal with he?  

提供替代取暖的时间点。

提供替代取暖器的可行性。

提供替代取暖器的有效性。

额外费用，取暖器和电费等的分担。

维修更新原取暖器的时间。

和房客耐心沟通。