Habitability requirements for rent?

[Kevin Kim]

We're about to buy a property in high desert area. 

In the property, there are 2 old manufactured houses: one is 1978, and the other is 1975. 

We want to flip little bit, and rent. 

The area is hot in summer, cold in winter, windy, and it snows too.

For now, there are fire stoves and small ac units which is installed on window in each manufactured houses. 

I'm not sure if those small fire stove and small AC unit is enough for the cold and hot season. 

There is no gas connected. 

Can you let me know what we need to fix to make the old manufactured house habitable, in other word, I want to know what we need to do to protect us from possible legal issue from tenants. 

Thank you.