The City of Boulder's solar access ordinance guarantees access, or "solar fences," to sunlight for homeowners and renters in the city. This is done by setting limits on the amount of permitted shading by new construction. A solar access permit is available to those who have installed or who plan to install a solar energy system and need more protection than is provided by the ordinance. For new developments, all units which are not planned to incorporate solar features must be sited to provide good solar access and [http://www.bouldercolorado.gov/www/publications/forms/116.pdf not shade adjacent structures]. They must also have roofs capable of supporting at least 75 square feet of solar collectors per dwelling unit. Non-residential buildings have similar requirements for siting. When applying for a [http://www.bouldercolorado.gov/www/publications/forms/816_PV_Solar_Check... permit], a simple [http://www.bouldercolorado.gov/www/publications/forms/818_Solar_Shadow_A... shadow analysis] must be submitted to the city’s building department.