Home Energy Monitors, that is, devices that display a home’s energy consumption have been touted as Silicon Valley’s contribution to the national energy conservation effort. A Home Energy Monitor (or HEM) constantly informs the occupants of their home’s electricity and gas consumption, along with conversions to monthly costs and comparisons with previous periods. Some models can (or will) communicate with heating and air conditioning systems. These devices will enable consumers to more carefully manage energy consumption and quickly identify energy wasteful practices. A better-informed consumer, the theory goes, will take more actions to reduce energy use. This scenario is consistent with our belief that if we deliver energy information to the consumer they will act upon it.
Unfortunately an article in this issue suggests that HEMs don’t automatically save energy (see “The Net Impact of Home Energy Feedback Devices,” p. 20). In fact, the energy savings were, as the authors succinctly concluded “not statistically different from zero”. Furthermore, the participants in the study were highly motivated and actually paid to get the meters. If these consumers don’t save energy then what can we expect from the larger population? This evaluation is not alone: a soon-to-be-released report reviewing a large number of studies found similar results. Other evaluations in Europe and Japan also observed little or no energy savings from HEMs.
HEMs suffer from a variety of drawbacks, ranging from clunky user interfaces to voracious appetites for batteries. At least one cynic has called the HEMs “a technology in search of a problem” because monitoring a home’s energy use appears to be a wonderful application of advances in local networks and low-cost processing. HEMs today are also dropped into a lonely, inhospitable world where few other devices communicate with the same protocols (if they are able to communicate at all).
One underlying problem is that energy consumption events occur relatively slowly and rarely require the bandwidth of a webcam or audio stream. Put another way, watching home energy use on a display or on the Web is boring. Most people lose interest pretty quickly. The high attrition rates found in the Oregon study demonstrate this phenomenon.
Meanwhile, we haven’t exploited the information flows that are already in place, such as monthly energy bills. An experimental project in Gainesville, Florida, demonstrates how disclosure of monthly energy information can encourage friendly competition among neighbors. And, beyond competition, people can learn that their neighbors enjoy lifestyles similar to their own but with dramatically less electricity, natural gas and water (see Figures 1 and 2). This is a first step towards reducing energy use.
In spite of the negative results so far, I still support the development and installation of HEMs. The technology is so cheap that a HEM can pay for itself even if it saves only a few percent of energy use. A HEM may pay for itself by alerting users to high peak electrical use where utilities charge extra for it. A HEM can also serve as a useful diagnostic tool (and data logger for a high school science project). In the long run, the HEM will become less lonely when appliances are able to communicate and provide information that consumers actually find useful. All of this calls for much stronger pressure on manufacturers toward harmonization of communications protocols and greatly improved user interfaces.
But we shouldn’t fool ourselves, consumers aren’t going to check the displays of their HEMs like they visit their Facebook pages, and HEMs are going to save, at best, a tiny amount of home energy.
These energy-monitoring displays appear indeed to be a contribution from Silicon Valley toward a national effort, but saving energy hardly seems to be its first outcome.Rather it’s saving very expensive peak capacity of electric utilities by helping consumers to shift use, which will save some energy, but the main selling point is saving money.That’s required in order for anyone who has one of these devices to even pay attention, it appears.It seems perfectly reasonable to see real action from consumers in response better information about peak price/use if it’s not too difficult and has real dollar savings.But where’s the energy savings?I am wary of a conversation covering efforts to conserve energy with a device that will likely have the effect of making energy use cheaper.
The monitors will however, through deployment in a peak-shaving capacity, allow consumers to build knowledge of how they might continue to live in comfort while using less energy around the clock, not just for a few hours each day, should they become compelled to do so.Maybe people really would check a HEM display as much as some do Facebook if they can’t afford not to.Especially if it’s just as easy to find out the ways your friends are using/saving energy.
Bill Henry
03-22-2010 2:05:16 PM
At the beginning of March, I began monitoring my home's electricity with the TED5000 and viewing usage on TED's home display, installed software, and Google PowerMeter. I am now certainly much more aware and knowledgeable of individual appliance power consumption levels. There are 4 other family members and I believe the in-home-display has raised their level of awareness in regards to power, cost, etc. If the monitoring device helps them to shut off a light or two - or the TV or Computer - when not in use, I think we can look forward to savings of 10-15%.
Adam Marks
04-08-2010 9:18:17 AM
Granted, HEM's that are installed and not monitored will not save any energy. The missing ingredient is knowing how best to use the information they provide. When a new system is installed and the display is placed in a prominent location in the house, energy conservation awareness or ECM increases for a short time. As the novelty of the new purchase wanes, so does the focus on the information it provides, unless there is a plan in place.
This plan should start with a 30-day baseline of recorded energy consumption in the home. Do not make any changes in normal usage during this time. After 30 days export the energy usage to a spreadsheet and use it as a baseline with which to measue future changes.
During this time perform an energy audit of each of the loads on the main circuit breaker panel using a whole house energy monitor and single point meter. Sub-metering, load profiling, net metering and placard data are all techniques that can be used to determine individual loads. Record this data in a table or use the 200 Amp Panel template available at www.home-energy-metering.com/home-energy-audit.html.
It is a free MS Excel download.
Although the process will require time and effort, it will give you a clear understanding of how electric power is used in your home. Vampire loads, unnessary equipment and other sources of waste will become clear. Armed with this information, make the changes that are practical and run another 30 day baseline. Compare it with your original and you'll know exactly how much a home energy monitor saved your home.
For more information and an explanation of the metering techniques noted above please visit www.home-energy-metering.com.
Howard Holmes
04-09-2010 7:50:51 PM
Home Energy Monitors are a great way to bring awareness but the nuts and bolts of it is you still have to properly insulate, use better windows and have an efficient HVAC system. That's where you get the greatest energy savings. There are lots of websites out there that have a lot of this information in a language that most people can understand, such as http://www.homeenergyguideswss.com
brian
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