Interest rates historically have been stable except during times of major financial distress in this country. The initial difference between fixed and adjustable rate loans is usually .5 to 2.0 percent interest. If you have to go to an adjustable rate loan to be able to make the payments you probably should not be taking out the loan. I am not a fan of adjustable rate long term loans. Adjustable rates on a 3 to 5 year loan is not an issue.
Adjustable rate loans are normally tied to one of the national bank rates. They will often have a limit on how much higher and how much lower the loan can go. Often they will also have a yearly adjustment limit, meaning they cannot go up more than one percent or .5 percent per year. Just the fact that your Home Loan payment can go up significantly is enough to scare me off an adjustable rate loan. Unless I knew that I was going to easily be able to sell my house and I would not sign up for one.