CREJ - Retail Properties Quarterly - August 2016
As an operator of retail properties, you’re always looking to cut costs and save money. When it comes to your energy bill, it is no kept secret that your roof is an important player in keeping your utility costs low and saving you energy. Within the past 15 years, reflective or “cool” roofs have been widely accepted as an effective, low-cost solution to energy loss and high utility bills, all while reducing the carbon footprint of the building. This trend has been so prominently accepted that large cities such as New York and Chicago have had the use of these products mandated for commercial roofing. And while cool roofs have proven themselves to work, there is a discrepancy often overlooked in their fervent promotion – location. Reflective roofs often are promoted with the general thumbs-up of approval, meaning its use has been interpreted to be equally effective and positive, regardless of location, climate and weather. However, research has shown that for northern climates, where heating often outstretches cooling costs, reflective roofs carry high heating penalties. White reflective roofs, when installed properly, can reduce cooling costs by reflecting ultraviolet rays off the roof, allowing the insulation to easily keep the buildings inside conditions, thus reducing the cooling costs. This same material – often made from white thermoplastic olefin or TPO – does the same reflecting process during the winter season, making it harder for the insulation to maintain heat in the building. During the summer and in southern climates, where the weather is generally warm, this type of roofing system makes financial sense. For northern climates, where a majority of businesses spend more on heating their building than cooling it, a reflective roof can be unfavorable, costing a business owner a bigger carbon footprint and hundreds in heating and wasted energy. As charted by Engineering Green Buildings in the February 2015 HPAC Engineering newsletter, most of the cities in colder climates were shown to have a significantly negative cost impact when using white reflective roofing. Let’s use a hypothetical 1-story, 10,000-square-foot retail building and compare the cooling benefit and the heating penalty of using a reflective roof in various colder climates. Denver, while having a cooling benefit of $168, ultimately suffers a $435 heating penalty with white roofing. Colorado Springs doesn’t do much better with a mere $124 cooling benefit, followed by a whopping $508 heating penalty. Other cities that take major losses include Portland, Washington, D.C., and San Francisco, whose penalty reaches past $700. Beyond costs and carbon emissions, reflective roofing in northern climates can cause condensation when not implemented properly. Because reflective roofing keeps the roof cooler, during the winter months, as the heat from inside the building rises, condensation begins to form underneath the roof membrane. While condensation may not cause a problem overnight, if not solved, it could cause mold, spores, rotting and eventual permanent roof damage. This problem, however, is easily avoidable with the implementation of a continuous air/vapor retarder or several layers of insulation. Condensation when present in single-layers of insulation can freeze and expand to tear the edges of the insulation apart. Take into consideration the R-value, defined as the “unit of thermal resistance for a particular material,” or simply the “thickness” of a material. The R-value is measured by “a solid materials resistance to conductive thermal transfer.” This means the thicker the material (the higher the R-value), the more resistant it is to thermal transfer. With the presence of several layers of insulation, moist air has a more difficult time reaching the underside of the roof’s membrane and causing condensation. Needless to say, when it comes to your roof, the type of material you use is important. Roofing is no one-size-fits-all rule. Much like real estate, it’s all about location. By choosing a quality-roofing contractor, you will be provided a cost estimate of the roofing materials best suited to your climate. That being said, regardless of the color, your business should schedule a yearly inspection to warrant the safety, durability and quality of your roof.