paying off loans faster than agreed time length

[Devon Smith]

My wife and I are looking into buying our first property to rent.  We already own our home outright and I'm looking to take out a home equity loan to get money for a down payment on a home loan.  My plan is to take out these loans at the longest time length possibly to pay them back.  ex. A 100,000.00 dollar home loan over 30 years.  I want to do this so that the monthly payments are as low as possible.  Then when it comes time to pay the bill I planned on paying the required monthly amount first; and then paying another amount towards the principle that way I could pay off the 100,000 in ten years instead of 30.  My wife thinks this will overall hurt our credit I think it could potential help our credit. please help