Energy-efficiency measures often offset their own cost by providing large savings on operational energy bills. These prerequisite requirements are directly tied to the benefit of efficient, low-cost operations.
With early design direction and energy-efficient fixture selection, lighting power density can easily be reduced by 10% with little or no additional cost.
Complying with the prescriptive method may require some additional time on the part of the design team to review and update compliance with each requirement. The mechanical engineer, architect, and lighting designer need to walk through the checklist to track the status of each requirement.
This prerequisite requirement is typically easy to meet. Most office computers and equipment are Energy Star-labeled and usually at little or no cost premium. Carrying out the calculations early on will tell you if the owner should specify more Energy Star-labeled equipment for the new spaces.
Most CI projects find it cost-effective to pursue the prescriptive option because of a limited design scope in HVAC systems and the building envelope, making the energy model of limited use as a design tool.
Developing a simulation model is an added expense and you may need it to provide a demonstrable payback if you’re going to use it as part of your compliance path. It can be well worth the cost, however, especially on larger projects with greater scope. If the scope of the project is larger (>100,000 ft2) and includes a central plant in addition to HVAC distribution and lighting, it can make sense to develop an energy model to assist in system selection and lighting design.
Many local incentive programs offer rebates for efficiency measures. Identify any available incentives at this time to inform your design decisions for equipment selection. Also look for incentives for energy optimization during the design process, like utility-funded energy modeling programs. (See Resources for help finding incentives.)
IAQ control measures can often be implemented at no cost and are quite feasible. However, the flush-out can be complicated by occupancy scheduling conflicts, or by system constraints that make it challenging to blow an adequate volume of fresh air into the space.
Because it can’t begin until all interior work is complete, the flush-out usually leads to occupancy delays. In tenant-occupied buildings, this can present financial challenges.
