Amber Wood, PE
Energy program administrator,
Department of Public Health &
Environment, Denver
Energy efficiency in sustainable buildings is positive for the bottom line and important in retaining tenants and enhancing wellness. Green buildings deliver 28.8% greater net operating income and have 17.6% less operating costs than non-green buildings, according to a U.S. Department of Energy study. Additionally, LEED-certified buildings eliminated 21,000 lost days of work and 16,000 lost days of school per year, a Harvard study found.
The first step on the path to energy and cost savings in buildings is Energize Denver and benchmarking, because you can’t manage what you don’t measure. Based on the Energize Denver data collected, buildings over 25,000 square feet saved 4% from 2016 to 2017. Results for 2018 will be out soon. This proves that you can save money and help meet Denver’s climate goals. Denver’s goal is to reduce building energy use 10% by 2020.
How can my building perform better? One of the first places to start thinking about a better performing building is by considering low-cost or no-cost energy savings upgrades. These include efficient lighting, a tune-up of your building (operations, scheduling, temperatures) and training staff.
How can I improve my building’s lighting? Efficient lighting is at the top of the list of energy upgrades because the payback typically is less than three years. Lighting and considerations for daylight also can enhance spaces and decrease fatigue. Workers in daylight office environments reported a 51% drop in the incidence of eyestrain, a 63% drop in the incidence of headaches and a 56% reduction in drowsiness, Cornell University found. There are a range of efficient lighting solutions for your building from good first steps to advanced ideas to innovative approaches.
Good step: Install LEDs. Installing LEDs in your building is a great start. LEDs are the longest lasting bulb. So while the initial cost is higher, they have a longer life than other lighting types and will need to be replaced less frequently. The payback typically is under three years for installing LED lights. For most bulb types, this is an easy swap where you can simply replace the current bulb with an LED bulb. One LED bulb costs $23 per year to operate compared with a CFL at $45 and incandescent at $186. How many lights are in your building? The savings can add up quickly.
To ensure an LED-replacement bulb performs as desired, consider the lumens (the illumination level) of the bulb, the temperature of the light (warm-red to cool-blue) and if the bulb is dimmable (detailed in the bulb specifications). The lower the wattage, the less energy the bulb will use and the less it will cost to operate.
There are a few special considerations for an LED upgrade, which are specifically for replacing either linear fluorescent or HID bulbs. The reason? Ballasts. While there are plug-and-play LED replacements for both applications, the savings will be greater if you upgrade to either remove the ballasts or replace the fixture. Typical paybacks still are under three years when doing this as a full replacement or fixture upgrade because of the additional energy savings.
Better: Include lighting controls. A more advanced approach to lighting is to add lighting controls in the form of occupancy and daylight sensors to an install of or upgrade to LED fixtures. The controls add flexibility in ensuring that lights are off during unoccupied hours and that spaces are properly lit with and without additional daylight through windows. The capital costs of upgrading to LEDs with controls typically have a one- to three-year payback range and usually are on the shorter side of that with automated controls.
Best: Mimic daylight with LEDs. Lighting design is increasingly more sophisticated with a variety of benefits. The Employee Experience study by Future Workplace found that 78% of employees said access to natural light and views improves their well-being and 70% report improved work performance.
Beyond installing LEDs and controls, building owners and managers can use controls to vary lighting temperature throughout the day to track more closely to daylighting. This strategy can reduce fatigue and increase productivity by scheduling lighting temperature by the time of day.
Another design methodology is to determine the lighting temperature needed based on the activity within a specific space. This scenario doesn’t require changing the temperature to match natural light, it matches the activity in the space to a lighting temperature. Lighting temperature has been shown to affect productivity by the color temperature of the light. Warm light is comfortable and relaxing, mid-temperature light is welcoming and can promote alertness, and cooler light enhances productivity and reduces fatigue.
Financing opportunities. As mentioned earlier, lighting upgrades have a payback of one to three years, depending on the lighting-design sophistication. There generally are two approaches to financing lighting upgrades. One approach is to view energy upgrades for your building incrementally. Start with the low-cost and no-cost items, such as lighting. Then, budget for more complex (and expensive) upgrades in the future. To assist with lighting upgrades, a wide range of rebates are available from Xcel Energy. Another approach, especially when heating, ventilation and air-conditioning equipment upgrades are needed in your building, is to wrap multiple energy-efficiency upgrades into one large upgrade package. While this has higher upfront costs, financing options like the Commercial Property Assessed Clean Energy program are available to support substantial energy-upgrade packages.
Final thoughts. Lighting demonstrates a commitment to sustainability to tenants, occupants and owners. Whether restaurants are using warm lighting to replicate candlelight for relaxation or office spaces using cooler light to mimic daylight to enhance productivity and reduce fatigue, lighting is integral to the use of a space. Upgrading to energy efficient lighting results in lower operating costs for buildings with happier tenants. Saving energy through efficient lighting is a bright solution for profit, people and our planet.
