This article was originally published in the November/December 1998 issue of Home Energy Magazine. Some formatting inconsistencies may be evident in older archive content.


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Home Energy Magazine Online November/December 1998

Home Energy Audits--Only a Web Site Away

by Helen Hunter

Utility Web sites now allow residential customers to review their annual energy costs and get energy-saving tips--right from their computers.


By linking the data that consumers input on the Web site to the consumers' actual bills, as well as accessing weather data and making some general assumptions, online audit programs can estimate how consumers use their energy, and suggest ways to conserve.


Fifteen forward-looking utilities are offering their residential customers a chance to perform energy audits on their own homes, any time of the day, for free. The customers can simply go to the utility's Web site, enter their utility account number, and spend 30 minutes answering questions on-line about their home, appliances, and usage patterns. Using a year's worth of that customer's utility bills, a software program goes to work estimating how much of their energy costs come from which end uses--a process known as bill disaggregation. Shortly after, up pops a report on estimated end uses, recommendations for ways to save energy dollars, and links to additional resources. At least one site even offers comparisons to energy usage in other homes in the same neighborhood.

Bill disaggregation tools differ from other types of energy analysis program in that they are 100% accurate on total energy use because they use actual billing histories. Other programs can only estimate total costs. (Breakdowns within categories, however, are only rough estimates in any type of program.) By linking a consumer's survey responses to actual bills, accessing weather data, and making some assumptions, these audit programs work back from a given total to estimate various end uses. Pie charts and graphs make the results visually appealing and easy to understand. The tools also identify where a consumer might cut energy use, and by how much. Some recommendations are general and are included in every report; others are directly related to the customer's input. A household might be advised to adjust thermostat setbacks, buy a more efficient refrigerator, install a reflective roof, and plant shade trees. At least one program, Electrotek Concepts, suggests that customers read specific articles in Home Energy magazine! Another significant difference between these on-line audits and other home audit programs is that the on-line audits provide the utility with marketing information and opportunities that other programs cannot produce. The utilities that offer the audits are a mix of public-owned and investor-owned companies; they have ideas and products to promote. They work with the software vendors to customize programs, and to add links to various resources such as libraries of additional information, on-line energy stores, on-line contractors, advisors who can answer specific questions, and catalogs.

These marketing opportunities can provoke consumer concerns about data security. Utilities buy on-line audit programs to enhance their images as service providers and in many cases to be able to target their marketing efforts. Without disclaimers to the contrary, there is nothing to prevent them from using data themselves or selling it to others. Many consumers may not be aware of this as a possible infringement of privacy. I feel that each utility should address this issue in its opening screens. A few do, but most do not.

Another security issue is the availability of survey data to hackers. This concern is somewhat offset by the fact that the surveys use account numbers only-no names or addresses are shown on-line. Hackers would have to be able to work all the way into the database records of the utility to gain information to satisfy their interests--perhaps for mailing lists and marketing information. These database records can be made as secure as any given utility cares to make them.

For at least one utility, security concerns are what has slowed the introduction of on-line audits. Pacific Gas & Electric (PG&E), a large California gas and electric utility with nearly 4 million residential customers, plans to offer an on-line bill disaggregation tool to their customers by the end of 1998. According to Duane Larson, PG&E's senior program manager for energy education, PG&E has delayed introducing their Energy Savings Plan interactive site until they are certain that no hacker can access their customer database. It's a new industry, he said, and we want to put in enough firewalls that consumers can be assured all utility customer records will remain confidential. The site will use the same software, developed internally, that has been used successfully for phone-in surveys from their Smarter Energy Line.

Case by Case For this report I reviewed the four auditing software programs that are currently available: Volt VIEWtech's HomeVIEW; A&C Enercom's Personal Energy Profile; Electrotek Concepts' Residential Energy Bill Analyzer; and Energy Interactive's Online Home Energy Audit. In my review of the demonstration sites set up to promote these programs, I found that each had its share of strengths and weaknesses. All four offered smooth interfaces. All allowed consumers to print the audit questions and return to the computer after they had gathered more data. Consumers also can save their inputs from one session to the next, which gives them an opportunity to correct input errors, make changes, and evaluate usage over time.

Not all programs, however, broke down usage in the same way or with the same precision. Some included data on gas; others let customers enter their own gas bill figures, depending on whether the utility sells both gas and electricity or only electricity. Generally, the accuracy of the bill breakdown is only as good as the questions posed, the answers given, and the assumptions of the program.

In the Volt VIEWtech site, users will be drawn into the survey by the opening question, Need Extra Money? and the catchy graphics inviting them to participate. Volt carries through with clear, cleverly illustrated results screens that make it easy to see where savings are available. The recommendations, however, left me puzzled. The first was a pitch--including an 800 number--to obtain a home energy savings loan with payments as low as $50 per month. Two minor recommendations followed to improve my already efficient home, for an estimated savings of $76 per year. It wasn't clear to me why I should obtain a loan.

The A&C Enercom site interface is clear and concise-perhaps too concise. The list of questions is short compared to the other surveys I used, which I assume leads to a less refined analysis. Some users, however, will prefer a survey they can scroll through rapidly. The most glaring flaw I found was that the program would not calculate results with none for a choice of air conditioners. I had to pretend I had one. On the other hand, the program let me slip by with no refrigerator!

Electrotek Concepts offers users a two-stage survey: heating and cooling only, with very little input required; and a more detailed version which includes appliances and other end uses. I liked the comprehensive recommendations-each one was highlighted in a box followed by educational information and suggested readings (primarily from the Rocky Mountain Institute and Home Energy). The recommendations may be overwhelming to--and go unread by--users wanting only a set of figures and a graph or two. Electrotek's rationale, and I agree with it, is that people taking the time to complete surveys should be given enough information to make it worthwhile--they can then choose how much detail they want.

The user interface for the Energy Interactive site provides multiple-choice answers which make responding easy, but this method lacks the precision of direct input. For example, I chose fully insulated for my ceiling, rather than partial or none. This response would not account for the significant difference between, say, R-6 and R-38 ceiling insulation. The recommendations appeared to have missed some of my inputs. They did not suggest that I replace an old, inefficient refrigerator with a new one, but I was advised to install a low-flow showerhead although I said I had one. Consumers may see such errors as minor irritations or as serious flaws that would make them doubt the validity of the entire report.

New Evaluation Just In A third-party evaluation of the accuracy of home audit software was recently undertaken by the Electric Power Research Institute (EPRI) in Palo Alto, California. An Evaluation of Web-Based Residential Energy Bill Disaggregation Software (report #TR-111192) was due out at presstime.

The report is a comprehensive review of how each program works, and a comparative analysis of their ease of use and features. It compares program outputs against each other and against metered data. Finally, it comments on the recommendations made in each program. It will be available at no charge to utilities that fund any of EPRI's residential targets. Others may call EPRI's Customer Assistance Center at 1-800-313-3774 or contact them via e-mail at

Do Audits Save Energy? If people buy efficient products, insulate more and better, and change their behavior in accordance with on-screen recommendations, then yes, on-line energy audits do save energy. However, if customers are advised by their electric company to buy a highly efficient electric water heater to replace a gas one, then no, they aren't saving energy--they are just being duped.

Whether or not home audits will save energy, they may save on consumers' and utilities' energy costs-at least in those areas where consumers are offered time-of-use rate structures. On-line audits can allow consumers to manipulate times they consume the most energy and then see the dollar savings appear on-screen immediately. If home audits convince enough customers to spread out electricity usage more evenly over a 24-hour period, utilities will gain measurable benefits from this leveling of peak electricity.
Web site:

Online Home Energy Audit
Energy Interactive Incorporated
2030 Addison St., Suite 600
Berkeley, CA 94704
Tel:(510)704-8777; Fax:(510)704-8760
Web site:

Home Energy Saver
Lawrence Berkeley National Lab
1 Cyclotron Road
Berkeley, CA 94720
Tel:(510)486-4835; Fax:(510)486-5394
Web site:

ENERGYsmart Web Audit
Nexus Energy Software Incorporated
233 Needham St.
Newton, MA 02164
Tel:(617)454-1050; Fax:(617)454-1051
Web site:

Energy Bill
Oarsman Corporation
P.O. Box 9056
College Station, TX 77840
Tel:(409)691-1368; Fax:(409)691-1369
Web site:

Volt VIEWtech
3430 E Miraloma Ave.
Anaheim, CA 92806
Web site:

Helen Hunter works as an energy consultant for compliance with California's Title 24 energy code and holds a Certificate in Energy Management & Design from Sonoma State University.


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