By December 31, 2009, to the extent that funding is appropriated specifically for the purposes of this section, the department of commerce shall develop and recommend to the legislature a methodology to determine an energy performance score for residential buildings and an implementation strategy to use such information to improve the energy efficiency of the state's existing housing supply. In developing its strategy, the department of commerce shall seek input from providers of residential energy audits, utilities, building contractors, mixed use developers, the residential real estate industry, and real estate listing and form providers.