By Nate Gillette, AIA, LEED-AP, CEM
Vice President and Director
Energy Finance Analytics, LLC
As operational costs continue to rise, many companies have become acutely aware of energy use in their facilities. By now, a number of these organizations have looked at and even implemented the so called “low-hanging fruit” of energy conservation measures. As the easier projects are implemented, building owners are often left wondering, “What’s next?”
Where are the hidden opportunities in energy efficiency in buildings? Some of them may surprise you, and may be more cost-effective than you think.
Reducing air infiltration has long been a little-understood factor when it comes to energy efficiency in commercial buildings. How tight or leaky our buildings are is often overlooked. Most designers acknowledge the issue, but only account for it in the design of the heating and cooling system. Fixing a leaky building is tricky and can go beyond one trade’s scope of work. Some studies indicate that as much as 30 percent of a building’s heating and cooling energy use comes from combating air infiltration.
The easiest way to measure infiltration for any building is with a blower-door pressurization and depressurization test. Many people are familiar with this procedure from its residential applications. The same concept can be applied to commercial buildings, usually with more fan power. This testing method uses a series of fans that pressurize and depressurize a building to a prescribed level, usually following the ASTM E779 standard. Coordinating work that will seal up the building in conjunction with the testing can give real-time results on performance gains. Costs will vary by project, but testing for a smaller office building of 3,000 square feet to 5,000 square feet might run $2,000 to $3,000. Conversely, a high-rise office building may cost tens of thousands of dollars to test.
Thermal imaging can be another invaluable tool to diagnose building energy issues, particularly when used with the air-infiltration testing described above. Thermal imaging involves analyzing the building with an infra-red camera that sees many things the human eye cannot. It can be used to observe where heat is escaping buildings as well as to detect water infiltration and possible mold growth spots, malfunctioning electrical equipment, roof leaks, plumbing leaks, and many other building aliments.
The use of thermal imaging and air infiltration testing together presents a powerful combination. When you thermally scan a building while the air infiltration testing procedure is taking place, air leakage becomes readily apparent. Typically the cost of thermal imaging is included with air infiltration testing work; when done separately, it can range from $1,000-$2,000, depending on the scope of work.
Retro-commissioning represents the third hidden opportunity to unlock a building’s energy efficiency. Buildings are very complex objects, with intricate systems that must work in harmony to provide energy-efficient, safe, and comfortable places for occupants. Many things can go wrong when key details are ignored. Motors may be wired to run backwards; heating and cooling systems may have control conflicts that allow both to run simultaneously; dampers may be stuck open or closed. The list goes on and on. For those unfamiliar with the commissioning process, think of it as a technical double-check of a building’s mechanical systems that assures everything is operating at its highest capability. After years of use, building systems can be modified or fall out of calibration, causing inefficient operation.
A commissioning agent can often identify these issues and help return a building to peak operation. The costs to perform retro-commissioning vary widely, based on the scale and complexity of a particular project. Large-scale buildings may run in the $0.20-0.30 per square foot range, while smaller or more intricate buildings may fall within the span of $0.60-0.75 per square foot. In many instances the operational savings that result from addressing the issues identified during commissioning pay for the costs of the commissioning process in very short order.
Getting beyond the basics and analyzing your building’s efficiency in further detail doesn’t have to break the bank. Cost-effective solutions for improved levels of energy analysis are also readily available. Don’t miss these opportunities to improve your building’s comfort and energy conservation capabilities.
The U.S. Green Building Council is a coalition of leaders from across the building industry working to promote environmentally responsible, profitable and healthy places to live and work. The West Michigan Chapter provides and develops leadership through affiliations and education at all levels. Please send comments and column proposals to email@example.com