Purchasing an energy-efficient product or renewable energy system for residential buildings makes owner eligible for a federal tax credit. Residential builders are eligible for a $2,000 tax credit for a new energy efficient home which is able to save 50% energy in heating and cooling of home. Out of the total amount of energy saved, 1/5 of saved energy should come from improvement of building envelope. Federal energy efficiency tax credit is also applicable for contractors of manufactured homes who follow guidelines of Federal Manufactured Home Construction and Safety Standards. A tax credit of $1,000 is applicable to manufactured home achieving 30% energy savings on heating and cooling over the 2004 IECC and supplements or for homes meeting established requirements by EPA under the ENERGY STAR program. It is to be noted that with the exception of the tax credit for an ENERGY STAR qualified manufactured home, tax credits are not directly linked to ENERGY STAR hence a builder of an ENERGY STAR qualified home may be eligible for a tax credit but it is not guaranteed.