Retrofitting an existing building with a system other than solar power, such as a biofuel system, low-impact hydroelectric, wind power, or other options is very unlikely for most situations due to cost, permitting, and infrastructure issues, as well as the suitability of the site.
Solar-thermal applications can offer attractive paybacks, especially for buildings with high demand for domestic hot water or hydronic heating, such as multifamily residential buildings, hotels, or other buildings that use boilers.
Solar photovoltaics (PV) and solar thermal are the most likely ways to integrate renewable energy into an existing building in a variety of sites and climates. Is there reliable solar access? Is there a rooftop or site area available to place panels? If a rooftop, can the roof support the additional weight and uplift?
Assess the feasibility of a new system, or adding capacity to the existing system. What type of system is the best fit? Consider regional and site factors such as solar access. Is there enough space to support the required equipment? Can a PV or Solar Thermal system be easily integrated into the existing electrical, heating, or domestic hot water systems? What is the likely payback, and does that work for the owner? Are there federal, state, local, or utility incentives for specific
Add a submeter to the system if necessary—it’s required for this credit. (You can’t rely on modeling or projections of how much power the system will supply.)
Offsite renewable energy, purchased through RECs and carbon offsets, usually has a smaller upfront cost and can be purchased easily and at virtually any time during the certification process if additional LEED points are needed.
Projects tend to pursue onsite renewables if they have an existing system, see value in the longer term payback, or want to make a prominent visual statement about the environmental facets of the building.
Solar-thermal applications can offer attractive paybacks, especially for buildings with high demand for domestic hot water or hydronic heating, such as multifamily residential buildings, hotels, or other buildings that use boilers.