Sustainable buildings are highly coveted, yet, initiatives are often dropped due to misconceptions that they carry higher initial costs. This statement may have been true in the past, but recent innovations in how we construct, create, and source have proven that the market is ripe for going green without going broke. At Tsoi/Kobus & Associates (TK&A), these promising innovations inspired a two-year study with AHA Consulting Engineers and Vermeulens Cost Consultants, that analyzed cost premiums associated with the LEED rating system. The result, “The Cost of LEED,”, published in 2010, is a first-of-its-kind tool for clients and practitioners to analyze LEED 2009 credit by credit, based on relative costs.
The challenge of putting together this study was how to deal with variability within the AEC industry. Several assumptions had to be made to narrow the focus. First, the costing data, such as LEED, was approached from the standpoint of a generic office or institutional building. , based on actual projects from the northeastern United States. during 2008, including materials, labor, and overhead. Since prices fluctuate, the team focused on percentages versus fixed costs, except where such information was consistent. (Percentages can adjust with fluctuations, remaining relevant. Items not included were soft costs, local variations, and life-cycle costing). An example of fixed-cost items is bicycle storage and changing rooms that come in conjunction with Sustainable Sites credit 4.2: Alternative Transportation. In evaluating this credit, an average cost was discovered as a function of the number of full-time equivalency occupants (FTEs). Essentially, bicycle racks cost $5 per FTE; enclosed bike storage (at $150 per square foot and 25 square feet per bike) costs $188 per FTE; and showers and changing areas costs $400 per FTE. Considering these figures, project size and occupancy density are the determining factors in the cost and number of bike storage and shower facilities needed per project—the cost being equally spread across the number of FTEs.
Table 1: An exampleHeat island effect for roofs directly from “The Cost of LEED”
One of the clearest examples is how to apply the study to roofs (Sustainable Sites credit 7.2: Heat Island Effect: Roof). Roof selection is an issue for debate, as compliance can be gained through a combination of high-albedo and/or vegetated roofs. Vegetated roofs are favorable for their beautification and performance, but their initial cost can be a major detractor. Here is how to use the study: a non-compliant roof (EPDM-black) is considered a base cost, or 100 percent of the total cost allocated for roofing. Other compliant roofs are shown as a percentage of the base cost with synergies to other LEED credits shown. This allows teams to demonstrate the cost of items not as singular entities, but holistically as vital components of overlapping systems. A tight budget may never consider vegetated roofs based on first cost; however, when considered in conjunction with other LEED credits, the cost becomes justified by demonstrating systems interconnection. This approach allows teams to assess the cost effectiveness and payback of each point to be viewed early in the design process so that they can identify the main cost drivers. Strategically, teams should choose credits with the greatest number of synergies, remembering that costs are shared, not additive; this reduces payback times and, potentially, first costs.
The study did uncover some surprises. First, there are several no-cost items within LEED, such as code-compliant items. These are not factored into cost premiums, as code compliance is required of any building, regardless of sustainable initiatives. Consider the LEED Energy and Atmosphere (EA) prerequisite 3: Fundamental Refrigerant Management and EA credit 4: Enhanced Refrigerant Management. These items require the location and planned phasing out of the harmful ozone- depleting refrigerants (CFCs) in buildings. As of January 2010, harmful CFC’s were discontinued in new HVAC equipment; thus, new buildings effortlessly satisfy these credits without any added costs.
Another trend has been diminishing premiums amongst sustainable products, such as waterless urinals, low-flow fixtures, and recycled materials. Better practices and increasing demand for sustainable goods and services have spawned a growth in industries that can deliver better products. Competition has begun to drive goods and services towards higher performance at costs associated with low-performance items. One example is the common rewarding of exemplary performance for construction waste management (as seen in MRc2.2 for 95 percent or more construction waste recycled, salvaged, and diverted from landfills). This barrier was a difficult one to break, but as it became a popular item, helped in part by the recognition provided by LEED, it spawned an industry consciousness and competitive nature that spurred others to strive for higher numbers. The current threshold for this credit gives one point for 50 percent diverted and two points for 75 percent of waste diverted. The key to its success as a popular credit lies not in that clients and project teams are stopping once they meet 75 percent, but rather that they are pushing forward at no additional cost to see how well they can do.
The study has proven useful at early design stages to aid designers and clientele, with various ranges of experience, in realizing the potential for systems and associated costs, benefits, and synergies. This study recently recently was presented at the 2010 Labs21 Conference in Albuquerque, N.M., and demonstrated how LEED credits can be synergized with the Labs21 EPC guidelines to substantially reduce construction and operational costs. For a 100,000-square-foot generic lab, it was proven that a higher- performing facility can be constructed at a lower first cost. Interestingly, the findings reveal that sustainable buildings can actually have lower construction costs than conventional structures- —providing the right credit synergies are discovered.
Blake Jackson, LEED AP, is the Sustainability Practice Leader at Tsoi/Kobus & Associates, Cambridge, Mass. tka-architects.com.