It may be important for you to have a lower initial interest rate, and subsequently a lower monthly payment, in order to qualify for the house of your dreams. If this that's the case, an Adjustable-Rate Mortgage might be best for you.
Stability in Your Monthly Mortgage Payments
With a fixed-rate loan, your monthly payment or principal and interest never change for the life of your loan. While your property taxes and your homeowner’s insurance premium may fluctuate, generally speaking, with fixed-rate loans, your payment will be very stable.
Fixed-rate loans are typically available in with terms of 10, 15, 20, 25, or 30 years.
A fixed–rate mortgage is a mortgage loan that has a fixed interest rate for the entire term of the loan. Generally, lenders can offer either fixed, variable or adjustable rate mortgage loans with fixed–rate monthly installment loans being one of the most popular mortgage product offerings. –Investopedia
During the early period of a fixed-rate loan, a large percentage of your monthly payment goes toward interest, and a smaller part toward principal. That gradually reverses itself as the loan ages.
A fixed-rate loan is a good idea if you want to lock in a low rate or would like to have a more stable monthly payment.