Energy Efficiency Auditing

Energy Auditing Overview

All energy audits start with the collection of energy use data of a facility, and then recommends ways to minimize waste, improve efficiency, and reduce energy costs. There is a wide variance among the different levels of energy audits, leading the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) to attempt to categorize these audits into three levels:

Level I:  Walk-through Assessment
In which energy bills are analyzed and, possibly, a brief visual survey of the facility is conducted. The subsequent report does not identify any energy efficiency opportunities.

Level II:  Energy Survey and Analysis:
Is a more detailed study, including a breakdown of how energy is used within the building. Potential opportunites are identified in the final report for further research and analysis.

Level III:  Detailed Analysis of Capital-Intensive Modifications
Focuses on capital-intensive opportunities. Detailed cost and savings information is included in the final report.

The auditing tools available from ECO Zero fall into the first two levels. The eQuickCheck family of audits, eXpressAudit360, and eBalanceZero are all Level I audits, helping to calculate a building's EUI and benchmark, identify areas for further study, and comparison of energy usage with utility billing. The remaining tools (eWeatherize, eLuminate, HVAC Engineering, eNvelopeAudit, and eNergyRenew) all provide more detailed studies and identify potential energy-saving measures.


eQuickCheck Standard,

eQuickCheck PRO

The easiest way to evaluate how well a building performs in terms of energy usage is to track this usage over time, establish a baseline, and then compare results with other properties with similar climate, size, operations and age (benchmarking). This comparison helps determine if a building's energy use is in line with expectations. While benchmarking can not identify specific energy saving measures, it can be used to identify those buildings where high energy usage merits futher detailed investigation.

The first step taken to benchmark a building is to calculate it's energy use intensity (EUI). This indicator is usually expressed as the annual average kBtu (kilo British thermal units) per square foot. Once this measure is calculated, the building can then be benchmarked. Curently, the EPA's Energy Star Portfolio Manager is the online choice of nine cities and two states as the energy use reporting and benchmarking tool. Portfolio Manager ranks buildings on a scale of 1 to 100, and awards an ENERGY STAR label to buildings achieving a score of 75 or higher.

There are three versions of the eQuickCheck family of audits. eQuickCheck5 is the simplest audit, designed to identify buildings where high energy usage points to further investigation. The standard eQuickCheck does a more detailed analysis of energy use in a building over a period of up to three years, and provides a degree-day influenced benchmark. eQuickCheck PRO adds Portfolio Manger reporting capabilties, and complies with all benchmarking ordinances in the nine cities and two states with such laws.


The preliminary or walk-through analysis gathers overall building information and data on major energy-using systems and equipment. Conducting a walk-through analysis will allow the auditor to identify functional areas of the building that are below standard and that should be targeted for additional study.

The eXpressAudit360 is the second step in the ECO Zero energy auditing process. While the eQuickCheck provides a building-wide measure, the eXpressAudit360 rates individual systems and equipment found in the facility. And while the results of the eQuickCheck provides a go/no-go decision point to continue with the audit process, the eXpressAudit360 identifies inefficient systems within the building for further study. By using the results of this study, the auditor can pick and choose from the following audits, conducting only those that have the greatest potential for significant cost savings. At the end of the day, the auditor's time is used most efficiently, and the client does not have to pay for system audits with little likelihood of unveiling worthwhile savings.


The basic idea of an energy balance audit is that nothing can get lost. But energy coming into a building is used by many different systems and appliances, and it is not always obvious to the energy manager which appliances and systems are consuming the most energy. And, since there rarely is an internal dashboard compiling totals of energy use by system, the energy manager must take the utility's bills as being accurate by blind faith.

For this reason it is important to determine if there is a balance between energy input (what appears on the utility's bills) and energy usage in the facililty. The eBalanceZero Audit from ECO Zero will tally all energy usage within the building and then compare this figure with utility numbers. In cases of major discrepancies, utility rebates may be in order.


Weatherization, sometimes called weatherproofing, is the process of protecting a structure from outside elements while also decreasing energy costs. Caulking, weatherstripping, adding insulation and replacing old windows with energy efficient alternatives can help weatherize a structure.

The high costs associated with weatherizing a structure often deter building owners from taking on such a project. If done properly, however, the retrofits made can be cost effective. Reduced energy costs are achieved largely because energy, such as heat, can no longer seep out of gaps and cracks in a structure. As a result, heating a well sealed building will require less heat and therefore cost less. In most cases, the costs of weatherizing are recuperated within a year of the retrofit. According to the US Department of Energy, weatherization reduces heating costs by 32 percent.

Weatherizing is most popular in homes, as opposed to commercial buildings. For older buildings, weatherizing may be partially accomplished. For example, windows may be weatherstripped. While this will help reduce energy consumption and therefore energy costs, it's not a complete approach. Whole-house or whole-building weatherization, on the other hand, goes beyond simple fixes to include replacing the structure's entire heating units, cooling units and appliances.

Weatherization not only helps a company's or individual's energy expenses, it helps the environment as well. As a result, many governments offer weatherization incentive programs. Each state in the United States, for example, have weatherization incentive programs.


A building's interior lighting is a complex system within any building. On the one hand, lighting consumes about one-quarter or more of a buiilding's electricity budget. Lighting can also be a major source of internal heat. And, on the human side of the equation, lighting had a direct affect on the physical and emotional well-being of the building occupants. In any lighting survey, all these factors and their inter-relationships must be accounted for when proposing changes.

When designing or changing a building's lighting system, more than just the fixtures should be taken into account. While a high quality energy efficient system is a good beginning, natural light sources as well as lighting controls must also be integrated into the plan. To achieve a quality lighting space, fixtures must be chosen to satisfy both performance and aesthetic needs, always remembering to limit the number of fixture and lamp types in order to achieve reasonable maintenance inventories. Lamp selection is based on lumens per watt, color temperature, color rendering index and cost, among other factors.

Any lighting plan should include daylighting. Daylighting, the controlled admission of natural light into a space through windows to reduce or eliminate electric lighting, has the potential to significantly decrease operating costs while increasing user productivity. Daylighting enlivens spaces and has been shown to increase user satisfaction and productivity. And the energy savings gained from reduced electric lighting can directly reduce building cooling energy usage.

eLuminate from ECO Zero provides all of the tools needed to design a cost effective and productive work environment. When completed, it will enumerate the steps to be undertaken, the changaes to be made, and the estimated returns on investments made in the lighting upgrade.

HVAC Engineering

Heating, ventilating, and air-conditioning (HVAC) systems account for about 40% of the energy used in commercial buildings in the United States. Consequently, almost any building has the potential to realize significant savings by improving HVAC operations and efficiency.

Each of the three disciplines above, along with controls to determine how the HVAC system operates, has opportunities for energy savings. It must be understood, however, that energy savings in one area may augment or diminish savings in another. This applies both to the interactions between the HVAC system components, as well as between the HVAC system and the lighting and envelope systems. Understanding how one system affects another is essential to making the most of the energy efficiency opportunities.

The HVAC Engineering Audit from ECO Zero provides a broad and structured approach to the analysis of a building's HVAC. All four components are analyzed and their interplay taken into account when making retrofit suggestions.


The term "building envelope" refers to the walls, roof, windows, and foundation of any building structure. The main function of the building envelope is to help maintain a comfortable climate for its occupants, ideally with the most minimal expenditures in heating during the winter and air conditioning during the summer. But many buildings are not adequately sealed, losing conditioned air through cracks in the wall, inadequate insulation, and drafty windows. An effective building envelope also adds to occupant comfort by blocking outside noise, protecting against weather, and maintaining indoor air quality.

Heat naturally moves from warmer to cooler objects, through the processes of radiation, convection and conduction. In the summer, the heat from the sun's energy radiates through the roof and into the building, adding to the cooling load on the air conditioning system. Convection refers to the air leakage through any openings in the building envelope. Conduction is the transfer of heat through a solid object such as a window - into the building during the summer months and out of the building during the winter.

The ECO Zero eNvelopeAudit tool has been designed to help the auditor find areas of the building that can be repaired and insulated, thus reducing the costs associated with cooling and heating. If focuses on understanding how the building gains and loses heat, identifying areas of the attic, walls, or foundation that can benefit from increased insulation, where air leakages can be sealed, and any cost-effective window improvements that be implemented.


Renewable energy refers to the energy that comes from natural sources such as wind, sunlight, tides, and geothermal heat. As energy resources like natural gas, coal, and oil become more expensive, renewable energy becomes more attractive and competitive. Generally, renewable energy projects are used on a large scale, however, this does not mean that renewable energy cannot be used in individual buildings.

In any energy efficiency program, the investigation of renewable sources of energy should be investigated as a last step. After the lighting has been adjusted, the HVAC system tuned, and the envelope weatherized, when energy use has been reduced to its minimum, it is time to evaluate the role of renewables at the facility.

The eNergyRenew Audit from ECO Zero investigates the feasibility of installing renewable technologies at a building site. Solar, wind and geothermal technologies are all evaluated.
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* May not be fully accurate!