Steve DeBusk 2016-01-08 17:51:46
There are many options to choose from when it comes to improving commercial building performance and reducing utility costs without breaking the bank. While investing in energy efficiency initiatives is a smart business move in most cases, it’s also important to find a balance between a project’s upfront costs and the expected return on your investment. It’s not often that making just one change to a facility can impact several areas of energy efficiency, but high-performance, low-e window film gives engineering managers that chance. Window film has been on the scene for decades; most energy efficiency experts know that window film can help control solar heat gain and reduce glare. But the right window film can offer several other performance and energy-saving benefits as well. Increase Insulating Power of Existing Windows The US Department of Energy declares that 25 to 35% of wasted energy in a commercial building is due to inefficient windows. But there’s good news: You can make existing windows more efficient without having to replace them. Almost like adding more insulation to walls or the ceiling, high-performance window film may add as much as 92% more insulating power to existing windows. As long as windows are in good condition (no cracks, moisture or leakage issues, or structural integrity problems), installing low-e film can give single-pane windows the same insulating performance as double-pane windows. It can offer double-pane windows the same insulating performance as triple-pane windows. Not only can this insulation help in warm months to keep solar heat gain at bay, but it can also help in cooler months when reducing heat loss is key to providing comfortable temperatures for occupants. Today’s new high-performance, low-e window film improves window insulation year-round in all types of regions and climates. Reduce Artificial Lighting Needs Despite the notion that window film may make spaces too dark and intensify interior lighting needs, it can actually do the opposite. A study at the University of Padua in Italy examined the MG Tower’s use of window film and its impact on lighting. This modern high-rise office was running up-to-date HVAC systems and had low-e glazing on its new windows. However, occupants were still feeling the effects of solar heat gain and glare: uncomfortable temperatures, difficulty completing tasks due to impaired visual clarity, etc. The study’s research team found that window film installation addressed these problems, and also provided a significant increase in the amount of available useful daylight. Unlike curtains and blinds (which can make spaces too dark and increase artificial lighting requirements), window film controls which UV rays enter through windows. By regulating the levels of heat and light passing through the glass, natural light can still enter without occupants needing to worry about exposure to UV radiation, glare, etc. With this increase in incoming natural light, artificial lighting systems may be able to remain off or be dimmed, which can also reduce HVAC loads. Prolong HVAC System Lifecycle To improve efficiency, many energy consultants suggest reducing heating or cooling loads as an inexpensive first step. This may allow your existing HVAC system to operate less frequently, which lowers operating costs and extends equipment lifecycle by preventing premature HVAC upgrades or replacements. One way to better manage heating and cooling loads is to control solar heat gain entering a building. In fact, the California Energy Commission estimates that 40% of a commercial building’s cooling requirements occur as a result of solar heat gain through windows. By improving window performance, you may also be able to keep heating and cooling systems from running as long or as often, ultimately reducing loads. To prove this point (and to measure actual energy-efficiency savings from low-e window film), the Hyatt Regency Houston recently installed low-e window film in 48 of its guestrooms. These rooms were located on the southwest- and southeast-facing sides of the building since these were the rooms that received the most temperature complaints. Using an extensive sub-metering system, heating and cooling energy use were measured in the 48 rooms with window film; the data was then compared to heating and cooling use in 48 southwest- and southeast-facing guestrooms without window film. The results were compiled by a third-party energy management consultant, and also verified by the local utility to help Hyatt Regency Houston qualify for a rebate. The results found that, in rooms with window film, both heating and cooling energy use decreased: heating energy use decreased by 25% and cooling energy use decreased by 23%. HVAC runtime was also significantly reduced; the HVAC system that once couldn’t keep guestrooms cool enough now provides enough cooling without retrofits or replacement. The hotel expects a full ROI in 3.6 years as a result of these energy savings. One other interesting note: According to the US EPA’s ENERGY STAR Building Upgrade Manual, 5% of US electricity is put toward counteracting waste heat generated by artificial lighting systems. If the use of lighting is reduced, as discussed earlier, there is also a potential to lower cooling loads. When artificial lighting isn’t used as often, there won’t be as much waste heat from the lighting system. A Smart Way to Save Energy High-performance, low-e window film is a cost-effective option to consider if a green building investment is in your future. A current ConSol study of California buildings pinpoints window film as the most cost-effective solution for energy savings and reducing carbon footprints, when compared to other energy efficiency improvements, such as air-leak sealing and caulking, adding R-38 ceiling insulation, or updating HVAC systems. The right window film can provide an impressive ROI, because it may prolong HVAC system life, improve the insulating power of existing windows, and decrease the need for artificial lighting. Steve DeBusk is global energy solutions manager for the window film division at Eastman Chemical Company.
Published by Forester Media. View All Articles.