Natural Resources Canada developed the EnerGuide Rating System to help home builders evaluate their house plans for energy efficiency and provide energy efficient upgrade options for customers. Your customers are looking for value in their new home. Natural Resources Canada has the tools, services and standards to help you build energy efficiency into your new home designs. The EnerGuide Rating Service starts with an analysis of the house plans by an energy advisor. The advisor will recommend energy-saving upgrades and work with you to define cost-effective options. You will then estimate the cost of the upgrade work, with a price for the various upgrades. Some builders prefer to carry out this energy analysis with their own staff however the final evaluation of the house must be done by an independent energy advisor. An EnerGuide rating shows a standard measure of your home's energy performance. It shows you (and future buyers) exactly how energy efficient your home is. The rating is calculated based on standard operation assumptions so that you can compare the energy performance of one house against another. The home's energy efficiency level is rated on a scale of 0 to 100. A rating of 0 represents a home with major air leakage, no insulation and extremely high energy consumption. A rating of 100 represents a house that is airtight, well insulated, sufficiently ventilated and requires no purchased energy on an annual basis.