We expect everything to be fast now. In fact, researchers warn that our expectations of instant gratification are creating a "culture of impatience" that is rewiring our brains and changing the way we interact with everything around us.

That's the case in the buildings sector, where a range of startups are battling to see which company can bring the fastest energy assessment to market. This push for web-based "virtual" and "no-touch" assessments is bringing stunning speed and transparency to energy-efficiency audits. But it also raises important considerations about the balance between quickness and quality of information. 

A look at two virtual auditors with very different models highlights how companies are striking this balance. 

Autodesk Sustainability Solutions, a group within the design company Autodesk, claims it has the fastest energy assessment tool on the market. In 2008, Autodesk acquired two firms with building modeling software to expand its auditing platform, called rapid energy modeling. Aniruddha Deodhar, the sustainable buildings program manager at the company, said the tool can deliver a basic model of a building in twenty or 30 minutes.

Autodesk is trying to find the sweet spot between rapidly deploying assessments based on limited information and ensuring that information is accurate. While other virtual auditing companies use meter reads and other energy consumption data to perform audits, Autodesk's software can create a model using only digital photographs, satellite images, aerial images and laser points. Some models are created using only a simple satellite image or a series of digital photos.

"Will it be super-accurate? No energy modeler worth his salt would throw a million dollars into a project based on this information. But it starts a conversation," said Deodhar. Autodesk's customers are currently running about 6,000 assessments per month through Green Building Studio, including new construction and existing buildings.

While Deodhar praised the work of other firms performing remote audits, he said many of the tools on the market are based on interval energy consumption data that may take longer to acquire or make the process more complicated. 

"Data is great if you can get it. But it’s not always there. You have to make do with what you already have. You can simply start with whatever you have and do the modeling quickly," he said.

The need for speed is critical. According to Autodesk, it would take 1,000 energy auditors working around the clock 365 days per year for thirteen years straight to assess the U.S. commercial building stock.

But speed can also compromise accuracy. In a white paper assessing a few of its rapid energy models, Autodesk reported that electricity consumption at one facility was radically different from what the company modeled. That was because the model failed to account for a data center attached to the building. The company also admitted shortcomings in modeling other non-electricity energy use like natural gas, which is highly variable and more difficult to predict than electricity consumption. 

The rapid energy modeling tool is a variation on traditional tools used in the architecture world that simulate a building based on physical configuration. By plugging in design conditions and creating a model of a building, an engineer or architect can compare the theoretical model to actual energy consumption. Reverse-engineering a building can be done very quickly. But analyzing the gap between the theoretical model and real performance takes more time, more data and more analysis than just building a simple model.

On the other end of the spectrum, FirstFuel performs inverse modeling by analyzing actual energy consumption data and weather conditions to understand how a building is performing.

"Instead of building a model from the bottom up, we just start with the actual data," said Swapnil Shah, CEO of FirstFuel. "Interval data can tell us what the building is actually doing. Compared with outside factors like temperature and humidity, we believe that’s a true representation of what’s going on in that building and where the opportunities lie."

Building an inverse model requires much more information upfront -- at minimum, a year's worth of hourly consumption data. But because the company works directly with utilities, Shah said acquiring the information is not a difficult process.

"Our path to market is through utilities. They are the central source and beneficiary, so in our model that is not a constraint," said Shah.

From initial assessment to verification through its team of engineers, FirstFuel can audit a building in a few hours and averages a few buildings per day. That may match the 20- or 30-minute audit like Autodesk is able to pump out with minimum information, but it's still a dramatic jump over the current manual auditing process, which can take a few days to a few weeks. And FirstFuel says it's a much more accurate picture of what's happening within a building.

PG&E recently conducted a six-month evaluation of FirstFuel's auditing process and found it was three times faster and four to seven times less expensive than conventional auditing. Autodesk is in the process of validating its tool at 32 Department of Defense facilities.

The differences in these two business models highlight the varied approaches companies are taking to virtual auditing. In Autodesk's case, it may sacrifice detailed energy data for speed in modeling; in FirstFuel's case, it focuses on higher-quality consumption data rather than pumping out more models. 

Other companies like Noesis Energy, Retroficiency, Sparc and Energy Results are also producing variations of virtual energy audits -- all using varying models and all targeting different customers.

Most of the virtual auditing companies agree that they're competing less with one another and more with the status quo (although they certainly are competing for brand recognition). There will be a range of successful companies in the space with different approaches to audits -- it just depends what kind of customer they're targeting.

For more on the activity underway in this sector, download our new free report, Intelligent Efficiency: Innovations Reshaping the Energy Efficiency Market.