[http://www.nmlegis.gov/Sessions/10%20Regular/final/HB0233.pdf HB 233 of 2010] exempted residential solar energy systems from property tax assessments. According to state law, for the purposes of determining property taxes, the value of a property cannot increase by the greater of 3% of the previous year's assessment, or 6.1% of the assessment from two years ago. An assessment may exceed these restrictions, however, if physical improvements are made to the property. HB 233 states that solar systems will not be treated as physical improvements, and therefore, will not increase the value of the property for property tax purposes. But future assessments will include the value of the solar energy system if the property is sold.
HB 233 defines a solar energy system as a system that provides space heat, water heat or electricity to the property. The term specifically does not include windows, dark-colored water tanks, or non-vented trombe walls.