Commercial buildings use a lot of energy. In fact, at 33 percent, energy costs represent the single largest line item in the typical building’s operating budget. Building owners will be happy to learn that smart design decisions can significantly reduce building energy use, particularly in lighting, which represents the largest category of energy use in commercial buildings.
Specifying energy-efficient lighting can go a long way to reducing the amount of energy required to illuminate a space. But other design elements can work together to drive down these costs, as well. For example, strategically placed windows and skylights can increase daylighting and reduce the reliance on artificial lighting. Daylighting not only reduces the energy costs associated with lighting; it also has a positive impact on occupants. Several studies have shown that improved daylighting yields higher sales; one study of retail stores conducted by Pacific Gas & Electric compared stores with skylights with those without such daylighting, and found that sales in the stores with the skylights were 40 percent higher.
Interior finishes can boost the effectiveness of lighting. This is due to the quality of light reflectance, which simply refers to the amount of light that is reflected off a surface. A color with a reflectance of 25 percent reflects 25 percent of the light striking it; the rest is absorbed as heat. In general, lighter colors have a higher reflectance than darker colors.
Materials with higher reflectance values permit more light from either artificial or natural sources to bounce off, enabling designers to effectively illuminate the space with fewer watts and fewer luminaires. High-reflectance finishes can also be used to enhance daylighting, as they help bounce and redirect natural light deeply and more evenly into a space. Floors, walls, ceilings, and even furniture and countertops can all play a role. Just as important, the layout design should ensure that furniture, displays and partitions don’t block daylight coming from windows and other sources.
High reflectance finish choices result in real savings. A Penn State study showed that a room with a high-reflectance flooring product (60 percent) saved between 18 and 19 percent in lighting energy costs compared to a room with low-reflectance (20 percent) flooring. That same study showed that simply installing a five-foot strip of high-reflectance flooring next to windows can increase daylighting levels in the center of the room by 5 to 20 percent. For more information on that study, you can download our whitepaper here.
Light colors have a higher reflectance than darker colors. But color is just part of the story. The uniformity of a surface also determines how evenly light is reflected. The smoother the surface, the more balanced the illumination. For example, light reflects more evenly off a smooth-textured wall or porcelain tile than it does a heavily textured wall or carpeting. The uniformity of the surface is especially important for ensuring daylight penetrates further into a space.
It’s important to note that finishes with higher reflectivity may require more maintenance to ensure the desired level of perceived cleanliness. Choosing a low-maintenance product with high reflectance can help satisfy energy-reduction goals without an increase in maintenance costs. For example, Armstrong Flooring Natural Creations Luxury Vinyl Tile (LVT) line includes high reflectivity options, and the products are protected with a special coating that resists scratches, scuffs and stains.
The savings in lighting energy can potentially be even greater if “smart” lighting controls and shading systems are integrated with efficient lighting and high-reflectance finishes. Such controls can automatically dim artificial lighting when daylighting meets illuminance thresholds.
In addition to lighting energy, finishes also impact heating and cooling energy. In general, a lighter surface will lower the cooling energy required, while a darker surface will reduce the heating energy and possibly increase the cooling energy. You will have to help your clients weigh the costs and benefits of a particular finish, which will depend on factors such as climate and building orientation.
Making these decisions early in the design process and working with other project team members such as lighting designers and architects will help ensure that all of these benefits are fully realized.
This helpful infographic illustrates the many enduring benefits that can be gained by making design decisions with long-term value in mind.