According to the U.S. Department of Energy, commercial buildings account for 39 percent of the country’s total energy consumption. Moreover, utilities account for nearly one-third of the operating costs for U.S. office buildings. High-rise buildings with aging infrastructure and dated HVAC systems in an extreme local climate can spend high above the average on utilities.
Yet, aside from HVAC and building design, a building’s windows are one place that can contribute to significant energy savings. Standard single-glazed, metal-frame windows increase HVAC loads, running up heating and cooling costs throughout the year. In addition, high-rise buildings are at a particular disadvantage. Due to their height, these buildings do not receive as much shading as low-rise buildings, and thus, they’re more prone to Solar Heat Gain – which is a measure of the amount of sunlight a building absorbs. In warmer months, solar heat gain contributes to higher cooling costs.
Considering that high-rise properties have hundreds, and even thousands, of windows, small energy savings measures can provide a noticeable ROI for property owners. So how can you save costs by investing in your window systems? Here are a few tips for improving the efficiency of your high-rise building’s windows:
- Install Reflective Coating
Today, the majority of commercial windows are built with Low-E coating, which is a protective tint designed to reflect solar heat. This helps reduce cooling costs in warmer months, by reflecting heat away from the building. Additionally, in colder months, Low-E coating helps reduce interior heat from flowing outside. After-market reflective coating has a similar effect, and these films can be a more cost-effective measure than replacing your property’s non-Low-E coated windows.
- Regular Inspections
Yearly window inspections are important for sustaining the efficiency of a window system. All components of the window system are examined, including the glazing, seals, frame and weatherstripping. In effect, common maintenance issues like poorly fitted seals, damaged frames and worn-out weatherstripping – all of which can diminish energy efficiency – are detected earlier before becoming a major contributor to energy loss.
- Regular Cleaning
Window cleaning indirectly affects efficiency in two ways. For one, window cleaning removes dirt and debris from the window system. Dirt and debris buildup can wear down the hardware and sealing over time, resulting in reduced efficiency. Additionally, clean windows let in more sunlight, which can help lower heating costs in cold-weather months.
- Replace Seals and Weatherstripping
Today’s window sealants are built to last, yet the materials weren’t always as reliable. Dated seals can cause a substantial amount of energy loss throughout the year. Replacing seals and weatherstripping will improve the insulating value of the window, preventing air from passing through the system in both directions. Plus, updating sealants will also reduce the risk for water damage, which instantly increases the risk for damage to the seal, frame and weatherstripping.
- Window Treatments for Lowering Solar Heat Gain
Window treatments like blinds and awnings prevent a building from absorbing heat, and they can be very effective. The Department of Energy estimates that west-facing awnings can reduce solar heat gain by up to 77 percent, while south-facing awnings reduce SHG by 65 percent. Additionally, blinds are an effective option for preventing heat gain. The DOE estimates that reflective blinds can reduce heat gain by 45 percent on a sunny day.
- Update Frame Material
Older buildings typically have frames built from metals like steel or aluminum. Metal frames are extremely durable and cost-effective, but they have a poor insulating value and are less efficient than non-metal options. Replacing metal frames with frames made of a non-metal material can contribute to energy savings. Frames made of wood, vinyl or fiberglass have a greater insulation value.
- Replace or Retrofit Dated Windows
The windows installed on aging buildings are commonly single-glazed windows with lower U-values. Today, owners have a range of options when it comes to replacement commercial windows, and even standard Low-E coated single-glazing windows can make a noticeable impact. In addition, double-glazed windows with Low-E coating greatly reduce overall heating and cooling costs, and the most efficient triple-glazed windows are also an option.
Windows are an integral part of every high-rise building. Yet, without upkeep, they can contribute to increased heating and cooling costs. Fortunately, the majority of these steps are cost-effective measures that will prove their ROI.