A production home is one that a home builder builds multiple times. Production homes are less expensive to build because of the economies of scale. The costs associated with designing the home and getting jurisdictional approvals is spread over more housing units. It's also easier for the construction trades to build the home since the workers will generally be more familiar with the design. Unlike custom homes, home buyers may not be able to change the home's layout; however, buyers can upgrade the features of the home by choosing better flooring, appliances or insulation. Some builders use computer-aided design technology to allow some changes to the layout of the home, for which there may be an additional expense. Builders typically buy or option a series of lots in subdivisions where they offer one or more floor plans from which their customers can choose.