When designing a building, the primary concern is staying within the budget, both during the construction phase and after the building is occupied. In order to do so, it is important to employ sustainable practices to satisfy that goal. By comparing initial costs with overall life cycle costs, it is generally found that designing sustainably reduces expenditures over the long term.

The outcome of sustainable building design is an authentic high performance building. Optimized over the building life cycle are energy use, water use, product use, indoor environmental quality, and operation and maintenance.

The results of this whole building design are aesthetic, cost effective, and functional buildings. During the sustainable design process minor design changes can produce big results. True stewardship of resources is achieved.

According to the Building Owners and Managers Association, the annual operation cost for a commercial building is nominal $6.50 per square foot per year. Utility cost (electricity, natural gas, and water), repair cost, and maintenance cost accounts for 58 percent of total costs. In contrast, the remaining 42 percent of annual building expense is cleaning, insurance, and taxes. Design choices will have little or no effect on these fixed costs.

In contrast, by strategic planning and design, it is possible to reduce life cycle costs that are associated with the dominant 58 percent of annual building expenses. For each design choice, a life cycle cost analysis is used to tabulate the present value of all expected costs. Escalation in energy cost can also be accounted for. Competing choices are then easily compared and ranked.

Scenarios
For example, an upgraded HVAC, lighting, building fenestration, or building insulation system choice may have a higher initial cost than a “base case” choice. However, the building or system upgrade may exhibit a lower life cycle choice that is manifested by lower energy, water, and maintenance costs and longer service life.

Additionally, the upgrade may be quieter, look better, require less indoor or outdoor space, and offer more redundancy in the event of a component failure.

This upgraded scenario is contrasted with choices that do not increase the cost of construction. Certain design choices may actually reduce the construction cost while achieving sustainable design outcomes.

For example, orientation of the building on the project site has an effect on summer energy and maintenance costs by minimizing the building solar heating effect. Regarding construction cost, with less solar heat load to contend with, the HVAC construction cost is lowered.

Strategic Placement
Besides proper site orientation, strategic placement of building fenestration to avoid west facing glass and favor north facing glass reduces HVAC first cost as well as energy costs. Improved indoor visual and thermal comfort is a welcome side effect.

Other design choices have a symbiotic response. For example, when a low energy lighting system is provided, the cooling requirement is reduced. This results in a lower HVAC first cost and also a lower HVAC energy cost.

Strategic placement of each mechanical room and each electrical room within the building does not add to the construction cost; however, a dramatic reduction in piping, ductwork, and electrical conductor construction cost is easily achieved. Energy cost is reduced as a result of the shortened flow paths. IEQ is improved since noisy HVAC equipment is situated away from worship spaces, classrooms, and meeting rooms.

Similarly, strategic sizing of each mechanical and electrical room provides optimal maintenance clearances which serves to reduce maintenance costs.

Integrated Design Team
Sustainable building design is made possible by integrated building design that includes a specific team process and an integrated design culture. An integrated design team is ideally situated under one roof and consists of both architects and engineers. The in-house engineering studios typically include civil, structural, mechanical, and electrical engineers.

The integrated design process and design team culture is in contrast to the traditional design team approach where the architect and engineers are working separately from different locations. The outsourced engineering consultants typically work in isolation where the opportunity for design collaboration is limited or non-existent.

The integrated design team members communicate and interact early and often during the sustainable building design process. The project stakeholders (integrated design team, owner, users, and builders) agree early on budget, goals, and objectives.

Project goals and objectives are held in the proper balance during the design and budgeting process. The interrelationships and interdependencies of all building systems are understood, evaluated, and properly applied and coordinated, all from start to finish. Off-the-shelf technology is combined with state of the art design. LEED certification may be considered as a method to gain recognition for sustainable building design.

After construction is completed and the building has been occupied for 12 consecutive months, a post occupancy evaluation (POE) is performed by the integrated design team to verify building performance.

The POE includes an energy assessment which tabulates the 12- month energy usage to determine the building energy use intensity (EUI). The prestigious Energy Star award as administered by the EPA is earned for buildings that exhibit exemplary energy performance.

High performance is the key outcome when designing a sustainable building. Ultimately, the goal is to manage the available resources for the best possible stewardship. 

Using the post-occupancy evaluation, the design team is able to compare energy consumption of a building adhering to sustainable design practices to other similar-use buildings. Through this energy use comparison, a facility can be documented and authenticated as a high performance building.

Gary Gabriel is director of sustainable building design at CDH Partners, www.cdhpartners.com.