The landlord and his wife, as tenants, what should I call them?

In the development of society, people's basic necessities of life are inevitable. Take you for example, people who are not local but work here, the unit has no dormitory or you like quiet, so you rent a house outside. The problem is that the landlord and the old couple don't know what to call them as tenants. If you are in your twenties and the old couple are over seventy, call them grandparents. If you know your last name and put it in front of your grandparents, no one will say such a thing. Going out is a trivial matter. You have to respect others to get their respect.