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The U.S. Department of Energy and the North Carolina Clean Energy Technology Center are excited to announce that a new, modernized DSIRE is under construction. The new version of DSIRE will offer significant improvements over the current version, including expanded data accessibility and an array of new tools for site users. The new DSIRE site will be available in December 2014. Staff are currently working hard on the new version of DSIRE but are also maintaining the content of the current version of DSIRE. Thank you for your continued support and patience during this transition. We hope you are as excited for December as we are!

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Incentives/Policies for Renewables & Efficiency

Printable Version
City of Boulder - Solar Access Ordinance   

Last DSIRE Review: 10/03/2014
Program Overview:
State: Colorado
Incentive Type: Solar/Wind Access Policy
Eligible Renewable/Other Technologies: Passive Solar Space Heat, Solar Water Heat, Solar Space Heat, Solar Thermal Electric, Photovoltaics
Applicable Sectors: Commercial, Residential, Local Government, Construction
Web Site:
Authority 1:
Municipal Code of Boulder 9-9-17

The City of Boulder enacted an ordinance in 1982 to guarantee access to sunlight for homeowners and renters.

Solar Access

Solar access is guaranteed setting limits on the amount of permitted shading by new construction. The degree of solar access protection is defined by either a 12 foot or 25 foot hypothetical "solar fence" on the property lines of the protected buildings. The ordinance is designed to protect access for a 4-hour period on December 21st. Under most circumstances, new structures will not be allowed to shade adjacent lots to a greater extent than the applicable solar fence.

There are three Solar Access Areas in Boulder based on a property’s zoning district. Depending on the applicable Solar Access Area, a lot is protected by a 12 foot solar fence, a 25 foot solar fence, or only through the solar permit process. 

Solar Access Permitting

A solar access permit is also available to those who have installed or who plan to install a solar energy system and need more protection than is provided automatically by the applicable solar fence. Once granted, a solar access permit is valid for the reasonable life expectancy of the particular solar energy system; a permit also expires if the solar energy system is not installed within 1 year after issuance of the permit or “has not functioned to fulfill its intended purpose for a continuous period of 2 or more years.” Permits may be renewed after expiration.

Solar Siting Requirements

All planned unit developments and subdivisions must be designed and constructed to provide good access to solar. Specifically, all residential units are required to have the following:

  • oriented within 30 degrees of a true east-west direction;
  • is flat or not sloped towards true north;
  • is physically and structurally capable of supporting at least 75 square feet of un-shaded solar collectors for each individual dwelling unit in the building; and
  • has unimpeded solar access through the ordinance or easements, covenants, or other private agreements among affected landowners.

Each nonresidential building with an anticipated hot water demand of 1,000 gallons a day or more must have a roof surface meeting the following criteria:

  • is flat or oriented within 30 degrees of a true east-west direction,
  • is physically and structurally capable of supporting a solar collector or collectors capable of providing at least 50% of the anticipated hot water needs of the building, and
  • has unimpeded solar access through the solar access ordinance or other private agreements that protect solar access for the roof surface.

Waivers of solar siting requirements are available to developers for a variety of reasons, such as if the proposed development incorporates additional energy resource and conservation options that exceed the requirements of the Green Points Building Program.

  Customer Service
City of Boulder
Building Services Center
P.O. Box 791
1739 Broadway, Third Floor
Boulder, CO 80306
Phone: (303) 441-1880
Fax: (303) 441-3241
Web Site:
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Disclaimer: The information presented on the DSIRE web site provides an unofficial overview of financial incentives and other policies. It does not constitute professional tax advice or other professional financial guidance, and it should not be used as the only source of information when making purchasing decisions, investment decisions or tax decisions, or when executing other binding agreements. Please refer to the individual contact provided below each summary to verify that a specific financial incentive or other policy applies to your project.

While the DSIRE staff strives to provide the best information possible, the DSIRE staff, the N.C. Solar Center, N.C. State University and the Interstate Renewable Energy Council, Inc. make no representations or warranties, either express or implied, concerning the accuracy, completeness, reliability or suitability of the information. The DSIRE staff, the N.C. Solar Center, N.C. State University and the Interstate Renewable Energy Council, Inc. disclaim all liability of any kind arising out of your use or misuse of the information contained or referenced on DSIRE Web pages.

Copyright 2014 - 2015 North Carolina State University, under NREL Subcontract No. XEU-0-99515-01. Permission granted only for personal or educational use, or for use by or on behalf of the U.S. government. North Carolina State University prohibits the unauthorized display, reproduction, sale, and/or distribution of all or portions of the content of the Database of State Incentives for Renewables and Efficiency (DSIRE) without prior, written consent.