The price per square foot is determined by the quality of the house and by the amenities and upgrades in the house. On New Construction it is the same . It is determined by what the total cost to the builder. Also , the price of building a house today is more than it was last year , 10 years ago , 20 years agoe, etc....You will pay less for an existing home than you will New Construction, but at the same time, once you do a home inspection it make cost you less to pay more in the long run. - Wed Sep 2 2009, 06:02