In the past few years, energy disaggregation technologies from companies like Bidgely and PlotWatt have moved from lab demonstrations to real-world applications, seeking to prove their accuracy in turning whole-building electricity data into itemized breakouts of how much is going to heating, cooling, lighting and different appliances and devices.

But for the most part, these systems have come to market through utility partnerships, as Bidgely has done, or through applications targeted at businesses that can use the data for broader operational goals, as PlotWatt is doing. Selling direct to homeowners is a tougher approach, since it requires a significant upfront cost for energy information that’s yet to be proven to be something most homeowners want.

Smappee wants to break that barrier. Founded by executives from the commercial and industrial energy management field, the Belgian startup started selling its home energy hub and cloud-based disaggregation analytics through Apple and Amazon stores early last year. Since then, it’s sold units to customers across Western Europe, as well as in South Africa, Australia and South Korea, Richard Morgan, business development manager, told me in an interview last week.

Smappee, which stands for "smart app for energy efficiency,” launched in the United States in December. Like many of the home energy products out there, it allows homeowners to monitor and, in some cases, control their energy use through smartphone or web-based control apps.

But unlike systems that disaggregate historical data, Smappee is delivering it in real time, adding an immediacy to its interface that shows minute-by-minute changes in household consumption,solargeneration, and the “always-on” or “vampire” load that comes from devices that silently consume electricity even when they’re off.

That could help Smappee’s customers save even more energy than the average 12 percent credited to systems of this kind, Morgan said. Smart-meter-connected systems don’t deliver data that fast, though companies like Bidgely are starting to offer in-home devices that pull second-by-second data from smart meters' ZigBee home area networks. 

Smappee’s utility-independent, real-time data capabilities come at a certain cost, of course. Its kit starts at $249 for a circuit panel-level monitor, home energy hub and one remote-controllable “smart plug” connected via low-frequency wireless. Adding three more smart plugs adds $40 to the price, and adding a monitor for a home solar system -- something a good number of Smappee’s early customers have already installed -- brings the starting price to $349.

That’s a lot of money, though it’s comparable to other circuit panel-level monitors like The Energy Detective that have seen some success among tech-savvy early adopters. It’s also no more expensive than more broadly successful home energy devices like the Nest smart thermostat, Morgan pointed out.

And because Smappee’s device samples home energy data thousands of times per second, it can deliver quite a bit more accuracy in its disaggregation than systems that pull 15-minute or hourly smart meter data for utility-to-consumer disaggregation services, Morgan said.

Diving down to itemized Bills -- with some caveats

These capabilities aren’t necessarily unique to Smappee, of course. Devices from Belkin and Intel that monitor home circuits have been put to the test in utility pilots over the past few years, though neither company has moved forward with consumer products. Startups such as Energy Aware are adding disaggregation to their home energy monitors, and PlotWatt has seen homeowners use its software in combination with data coming from third-party hardware systems.

But Smappee is putting its confidence in its accuracy to a test that most others in the business haven’t yet, with this week’s launch of what Morgan calls “the world’s first itemized utility bill for the masses.” Unlike most energy disaggregation systems, which tend to stick to only the largest loads in the home such as air conditioners, refrigerators and clothes washers, Smappee’s newest app is gunning for devices down to microwaves, coffeemakers and lights from different rooms in the house.

All this itemized data comes with certain conditions, of course. First, getting down to this nitty-gritty detail requires that customers interact with the system, turning appliances and lights on and off to help the system identify which alterations in main circuit data correspond to which loads. That’s a technique put to use by other energy disaggregation systems, but it might turn off some customers.

“The smallest load it’s detected in my home is an iPad charger,” Morgan said -- but it’s hard to predict how small the disaggregation algorithms will be able to go. “Some homes may be better, some homes may be worse. It completely depends on how 'noisy' the home is, in terms of how many appliances are coming on and off all the time.”

Second, turning kilowatt-hour measurements into dollars-and-cents measurements requires homeowners to input their electricity rates on their own, he said. That can get tricky for more complex rate plans, like California’s tiered rates that rise during the month -- something that Smappee doesn't support at this time. It’s also not going to yield a perfect outcome at the end, which means that the itemized cost figures for all the appliances in the house might not add up to the total home consumption listed at the top of the screen.

“From the consumer feedback we’ve had on the testing of this, they’re pretty comfortable in inputting their rate structures, and in knowing it’s not going to be exactly accurate to the cent,” Morgan said. “We will never get to 100 percent correct, because of the nature of how disaggregation works.”

These are all issues that every energy disaggregation provider will need to deal with, as we’ve noted in previous coverage on the subject. “We don’t want people thinking this is rubbish, because after 24 hours it hasn’t detected all of the appliances in the house,” he said. “All this expectation management is really important with this type of technology, so they’re not expecting every number on the itemized bill to match their utility bill exactly.”

Of course, as with every other disaggregation technology, the question that may be hardest to answer is how accurate it truly is. The utility industry and would-be technology development partners like the Department of Energy are looking for common test methods and metrics on this front, to allow apples-to-apples comparisons of different technologies and techniques. We'll have more on this subject later this week, but suffice it to say, it's one of the more controversial subjects in this emerging field.