Legal Question in Landlord & Tenant Law in California

It depends upon how often the temperature goes up so that it might be necesary to have the air conditioning set to go on when it reaches 78 degrees. If that happens only 2-3 days a month in the summer, you may not have a case. If the prior rule was 80 degrees then it might be considered a minor change. if the rule was never clear and he told you to clarify the rule is migt be ok. Otherwise notice would have to be given as part of a new lease with your getting 60 days notice because you have lived ther more than a year. But before getting the landlord mad at you, see if something can be worked out.

If there are multiple boarders, I agree with Mr. Shers. If you are the only person renting a room in the house, special rules apply that would further limit any need for notice.