Although building energy efficiency is improving, the sector still falls disappointingly short of meeting its full potential.

Even when a building owner or manager goes through the process of an audit and retrofit, results can be inaccurate and inconsistent, especially when compared across an entire portfolio. There are many reasons for this shortfall, but it essentially comes down to two factors: people and tools.

The people factor is real; the diligence of the audit team and the skills of the retrofit installers can change the results of an energy retrofit drastically. But for now, let’s talk about the tools.

The toolkit of an energy auditor largely consists of technologies that have been around for decades. Though effective in the right hands, blower doors, thermographic cameras, etc. only provide a snapshot of the efficiency of a building. The trouble with this is that it doesn’t help auditors anticipate exactly what effect different energy conservation measures will have on overall consumption. Instead, through experience and training, auditors give an estimate of how much a retrofit will improve the building efficiency, and then take another snapshot after the measures are installed. The hallmark of the growth of clean energy has been the relentless improvement of technology, but can the same be said for energy efficiency?

While it’s unlikely that there will be a revolution in blower doors any time soon, energy modeling technology has made great strides in recent years.

Even the concept of “remote” energy audits has taken hold as a way to provide energy reduction recommendations without the cost and time involved in a walk-through energy audit. By using geographical information, utility data, and basic building characteristics, these reports evaluate the energy efficiency of a building and make recommendations without ever setting foot inside. Some hailed the rise of remote energy modeling as the solution to tedious walkthroughs and manual reports. Others reacted skeptically to the idea that collecting a few pieces of information could come close to substituting for a comprehensive audit. But there seems to be middle ground emerging: the use of mobile devices and powerful software to create complex energy models during the auditing process.

The National Renewable Energy Laboratory (NREL) has led the effort, enlisting the help of several disparate internal initiatives and the private company concept3D to create a high-tech solution called simuwatt Audit. This project integrates a cloud-based library of energy conservation data, an established whole-building energy simulation engine, and advanced building geometry capture software into a single tablet-based software tool. Though complex technologically, NREL hopes that simuwatt Audit will facilitate faster and more accurate data collection and accelerate the identification and analysis of potential energy conservation measures. By essentially combining the best of both the virtual audit and the onsite assessment, this software aims to reduce cost of walk-through audits and increase the information input (i.e., accuracy) of rapid energy modeling.

The database for simuwatt Audit is the Building Component Library (BCL), an online repository of energy data on individual building components and energy conservation measures. This program allows auditors to download a component (lighting), or a conservation measure (adding overhangs to all of the windows) and insert it directly into their model. The large-scale analysis capabilities of such a vast data bank will provide robust performance metrics on a wide range of retrofit technologies and measures and also allow portfolio managers to measure their stock against a statistically significant baseline.

The simuwatt Audit program takes its energy modeling component from NREL’s OpenStudio Platform, which uses the data collected during the audit along with the BCL to produce a whole-building energy model and analysis. OpenStudio leverages Google SketchUp to create detailed 3-D building and system renderings based on building geometry, envelope, plug loads, people, daylighting and more. It is not so different from other energy modeling software, except that it is free and open-source, which means that development teams are able to either add plug-ins based on their specific situation or submit code to NREL which may be integrated into the platform. This ability allows for the rapid development of new applications of the software and a level of customization not found in other modeling software.

Finally, the energy information is integrated into the concept3D geometry capture software, which allows users to draw a 3-D building model as they perform their assessment. The costs of an energy audit are often driven higher because of multiple site visits and the process of recording and modeling efficiency upgrades separately. By allowing auditors to build the model as they go through the building, they not only save time, but also reduce the likelihood of errors in manual data transfer. The concept3D software will also make multi-building analyses more streamlined, a feature that is crucial when analyzing an entire campus or portfolio due to the volume of documentation an auditor accumulates during the process. These savings are not marginal; NREL has set the goal of a 75 percent reduction in cost for investment-grade level III audits from using this technology.

The combination of site-specific, immediate model creation with aggregation and large-scale analysis capabilities should drastically improve the toolkit of the energy auditor and the industry as a whole. When realized, this technology will enable smaller teams to conduct more accurate audits while reducing costs. The Department of Defense’s Environmental Security Technology Certification Program has announced that it will demonstrate simuwatt Audit on a number of facilities, including West Point and the Air Force Academy in Colorado Springs. Should these and other demonstrations be successful, concept3D, which holds an exclusive license to commercialize NREL’s audit framework, plans to roll out the product in the beginning of 2014.

As part of the simuwatt Audit program, NREL is also tackling the problem of people by piloting an advanced BPI Certification that outlines detailed workflow process for auditors, but the introduction of simuwatt Audit itself is a big step into the future. While this technology will likely not replace the standard toolkit of an energy auditor, it will make the toolkit more powerful and effective than ever before. If simuwatt Audit can actually reduce the cost of the audit and provide scale to the energy auditing industry, the massive potential of building energy efficiency may actually be realized.


Comly Wilson is a Research Associate at CleanEdison, a national provider of clean energy and energy efficiency training and certification courses. He studied Energy and Environmental Policy at American University and now lives in New York.