With tax time approaching, the word “audit” can conjure up some unpleasant images. An energy audit, however, works in your favor. By detailing where and how energy is used in your facility, an energy audit can equip you with the knowledge to lower operating costs, and provide a roadmap for improvements tailored to your specific facility. It’s a powerful tool to help existing buildings meet – and even exceed – your energy goals.
Often conducted by an outside source, an energy audit provides a comprehensive picture of how energy is utilized, conserved, and potentially lost in your building. For those pursuing LEED for Existing Buildings: Operations & Maintenance (LEED-EB O&M), an ASHRAE Level 1 walkthrough assessment – a basic energy audit – is actually a prerequisite. But, there are compelling reasons to conduct an energy audit even if you’re not seeking LEED certification – it identifies opportunities to control costs despite rising utility rates, and can assist you in reducing your building’s impact on air pollution.
An energy audit has two main facets: the assessment and the final report. The process begins with a qualified engineer, who performs an onsite review of the facility’s energy-consuming components:
- HVAC equipment – including chillers, boilers, and the air-handling system.
- Building automation.
- Domestic hot-water system.
- Process loads (if any).
Then, the engineer examines the building envelope, checking the wall construction, roof, insulation, and glazing for possible leaks. Information collection follows. The audit requires 1 year’s worth of utility data and, if the facility has been ENERGY STAR® benchmarked, that information is considered as well. During an interview, the assessor assembles information on the building’s hours of operation, housekeeping schedule, and running times for the equipment, as well as the types of controls (automatic or manual) the building relies on.
By evaluating the utility bills, trend data, and equipment operational schedules collected, the assessor makes sure all of the systems are working together. The engineer creates a breakdown of all the energy end use, showing what percentage of the total energy use is associated with the various systems. Usually, this information is formatted into a pie chart, with slices designated for HVAC equipment, lighting, plug loads, domestic hot water, and process loads (if applicable). The chart can instantly highlight areas that require attention. For example, if the lighting load represents 40 percent of the total pie, the next step would be to examine ways to reduce that escalated figure.
The assessor develops a list of energy-efficiency measures (EEMs) and their associated costs. For each measure, the report correlates the energy savings based on current utility rates, and calculates the return on investment. EEMs fall into two categories: the no-cost or low-cost category, and capital improvements.
An example of a no-cost EEM would be changing the operating schedules of building equipment. In some cases, the assessor finds that certain systems are running more than they need to be, and that simply operating them less would not impact the building function, but provides a free solution to energy savings. If the engineer discovers a failed economizer on an air-handling vent, fixing or replacing the economizer would be a low-cost way to conserve energy, as it would reduce the chiller’s hours of operation. Most no-cost or low-cost items can be implemented immediately, and have a payback of less than 1 year.
Capital improvements identified usually have a larger payback period, from 1 to 2 years up to 20 years-plus, depending on the EEM. For example, it’s fairly common for an energy audit to recommend installing variable frequency drives on motors, a practice that pays for itself within 2 to 5 years.
For EEMs with a larger price tag and longer payback period, utility and government incentives can lighten the financial burden to speed up the return on investment. Check with your utility representative about incentive programs and options. If they don’t provide them, chances are good that they’ll be able to direct you to someone who does. Check into all the programs in your area, as each one will offer different alternatives. Some programs even fund the energy audit.
Other items that complement an energy audit are a Building Operations Plan, a Systems Narrative, and a Sequence of Operations. LEED-EB O&M also requires that these documents be submitted. A Building Operations Plan details the protocols for equipment, such as the thermometer setpoints, when the equipment is turned off and on, etc. Often, this information is stored only in the minds of building engineers and maintenance personnel. Getting these details down on paper is a best practice that ensures that everyone who operates the equipment is on the same page, and becomes invaluable when facing turnover.
The Systems Narrative and Sequence of Operations document how the building systems work. These reports track information, such as what type of system is operating, the specific equipment that constitutes the system, what is involved in the heating/cooling/air-conditioning processes, their sizes and capacities, how they’re activated, and how they’re configured. Recording this information requires you to carefully examine what you have, and becomes a handy resource as you consider which components of the energy audit to implement.
An energy audit brings new opportunities to light. It can reveal undetected weaknesses in the function of your building, and provide you with options that save money. In addition to enhancing your current building performance, an energy audit will serve as a valuable tool in planning and budget preparation for future improvements.