Energy efficiency makes good business sense. So how does one get started lowering energy bills and improving buildings’ energy efficiency? First you need to know how much energy you are currently using, and then you need a plan on how to change that.
- Step 1 – Benchmark your energy consumption to know how much energy you consume and how that compares to other similar buildings.
- Step 2 – Perform an Energy Audit (or Energy Assessment) to identify strategies to reduce your energy consumption and know the payback of those strategies.
Benchmarking is a way to simplify all of your energy bills into one clear value, allowing you to track and compare your building. The two most common benchmarking units are an Energy Use Intensity (EUI) and the ENERGY STAR® Rating. An EUI is the energy consumed by a building relative to its size. An ENERGY STAR® Rating is your building’s energy performance on a scale of 1-100, with a score of 50 being an average building. An ENERGY STAR® Rating is a ratio of your actual EUI to what you would expect your building’s EUI to be when adjusted for use and climate.
An energy audit looks at all the ways your building uses energy and identifies ways to use less. Typically performed by a third party, an energy audit will identify strategies called ECMs (Energy Conservation Measures) or EEMs (Energy Efficiency Measures). Keep in mind your building is a system. A change you make to your building envelope may affect your lighting, a change in your lighting may affect your HVAC system, a change to your HVAC system may affect the building occupant’s comfort. Any EEM you are considering should be considered from the perspective of the whole building and not in a silo.
The industry standard for energy audits follows guidelines set by ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers). These guidelines outline the scope for progressive levels of energy audits. As the energy audit ‘level’ progresses, the quantity of EEMs identified increases and the accuracy of the cost and savings calculations increases.
- Level 1 Audit: benchmarking, plus low and no cost EEMs identified with their estimated cost and savings, and potential capital improvement EEMs identified.
- Level 2 Audit: Level 1 Audit, plus a breakdown of the end-use of energy, a larger number of EEMs identified with a more detailed analysis of the cost and savings, and recommended EEMs based on operation and maintenance changes.
- Level 3 Audit: Level 2 Audit, plus additional measurements of energy use taken, an hourly simulation of energy consumption provided, a larger number of EEMs identified with a refined analysis of the cost and savings, and recommended investment grade EEMs.
An energy audit is not required to be one of the ASHRAE levels. Your energy auditor should work with you to define a scope that addresses the level of detail you need, the areas of concern you have, and how it can fit within your budget.
Want to know more? The Department of Energy’s Building Technologies Program created ‘A Guide to Energy Audits’ that provides greater detail on energy audits, advice on hiring an energy auditor, as well as a sample RFP. <<link to the PDF http://www.pnnl.gov/main/publications/external/technical_reports/pnnl-20956.pdf >>