Savings from Daylight Harvesting Varies with Occupancy
Daylight harvesting reduces lighting energy consumption by using natural light to offset electric light in perimeter workspaces. A study of five federal buildings found that daylight harvesting provided an average annual energy savings of 27 percent.
However, the study found increased savings from occupancy control left little room for savings from daylight harvesting.
GSA’s Green Proving Ground (GPG) program commissioned Lawrence Berkeley National Laboratory to assess the performance of daylight harvesting at five federal building sites, for the report “Integrated Daylighting Systems.”
The five long-term study sites with active daylighting averaged annual energy savings of 0.84 kWh/ft2 or 27 percent. Payback ranged from 4.3 to 17.6 years, with three of the five sites realizing simple payback of less than 6 years. Two sites would have had more attractive payback if they had been occupied a larger percentage of the time—greater use resulting in greater savings.
The report recommends deploying daylighting technology where existing lighting use is high. As a rule of thumb, daylight harvesting becomes cost-effective at an installed cost of $1.40/ft2, with a utility rate equal to the national average of $0.10/kWh, assuming dimming ballasts are already in place.
- Integrated Building Optimization
- Alarms Management: The Future is Now
- Six Essential Steps to Drive Effective Energy Management
- How to Use Lean Tools to Cash In On Environmental and Energy Savings
- BuildingIQ Security
- Mobility From The Plant Floor To The Store Door: Improve Safety, Accuracy, and Productivity
- Sustainability Reporting for Commercial Real Estate: GRESB
- EHS Managers: The Evolution from Necessary Evil to Vital Leaders
- The Guru’s Guide: Implementing Environmental ERP Systems
- Top 3 Reasons to Calculate Your Environmental Footprint
- Energy Efficiency Requires Engineering Efficiency
- Integrated Building Optimization: A Crucial Convergence of Demand-side and Supply-Side Energy Management Strategies
- Driving Productivity and Profit with Industrial Energy Management
- Energy Procurement in 2014: Products & Programs to Optimize Savings
- BUYING STRATEGIES IN A VOLATILE MARKET: What Businesses Need to Know about Retail Electricity Procurement