Jim Walsh waves a strange-looking wand at an electrical outlet in the model home of a new housing development. White smoke puffs from the glass tube and is sucked rapidly out of sight.
Mr. Walsh grimaces, shakes his Beatle-cut head of hair, and mutters, "Energy down the drain." As founder and president of Computerized Energy Audits Inc., he is one of a handful forging a new profession, that of home energy auditor. This morning, he and an assistant are testing the passive solar house design of an energy-conscious developer. As the result of his investigation, he will give her some suggestions on how to make her homes more energy effficient.
For $175 he will give your house a thorough energy checkup and prepare a list of the various steps you can take to cut down your energy bill, with an estimate of how cost effectively they will be. For a bit extra, he will come back and retest your house after you have insulated, caulked, or taken whatever energy-saving steps were advised, to ensure that they have been done correctly.
In the last five or six years, large companies have been able to get professional advice on how to reduce their energy bills, but the homeowner and small-business man have been left out in the cold. According to sources at Princeton University in New Jersey and the Lawrence Berkeley Laboratory in California, leaders in this area of energy research, there are only a couple of dozen companies around the country that do instrumented home energy audits of the sort that Mr. Walsh performs. For the last year or so, utilities have been required to give their customers energy audits for $15, but experts in the field give them generally low marks for the quality of their efforts.
The potential energy savings for the nation and dollar savings for the homeowner from sophisticated energy audits and follow-up conservation measures appear to be substantial. Dr. Gautum Dutt, head of Princeton University's House Doctor Program, estimates that this could save fully half of the nation's energy consumption for home space and water heating. This is roughly equivalent to a saving of 1.5 million barrels of oil a day. "Even on well-insulated houses we find reductions of 25 percent are possible," explains Dr. Dutt.
"On average the conservation measures we suggest have a two-year payback," Mr. Walsh estimates. Often the suggestions he makes vary substantially from those given by utility company auditors, he says. That is not surprising, given the difference in basic approach.
most utilities rely on a visual inspection of the home that takes one to two hours. This is combined with records of a household's energy consumption and run through a computer to give the paybacks for a laundry list of 15-odd energy conservation measures. "They sacrifice accuracy by taking shortcuts, by making assumptions rather than taking measurements," observes Bruce Dickinson of Lawrence Berkeley Laboratory. Dr. Dutt says that purely visual inspections of this sort can overlook the sources of fully 60 percent of a home's unnecessary energy loss.
In contrast, Mr. Walsh shows up in his aging truck with a device called a door fan. This is a powerful fan mounted on plywood which fits into the front doorway. When cranked up to full speed, it fills the house with a wind-tunnel howl. The fan is used to put the house under both positive and negative pressure. This has two uses:
Measuring the pressure created by running the fan at different speeds, Mr. Walsh gets a general idea of how tight a house is. Then, keeping the house pressurized, he tracks down specific sources of energy loss from air leakage, or infiltration, using a smokestick. It is quite an education to se the smoke sucked avidly into electrical outlets, lamp fixtures, around masonry walls, and through the cracks in sliding glass windows.
The audit also includes an analysis of furnace efficiency. "We've found that many furnaces are running at 40 to 50 percent efficiency, rather than at the 65 percent which they should be," mr. Walsh reports.
Combined with a determination of the insulation in a house, these measurements are fed through a desktop computer. Based on this, the computer determines the most cost-effective combination of energy saving steps.
"This sort of optimization is one of the most critical aspects of an audit," says Lawrence Berkeley's Dr. Dickinson. Sometimes laundry lists of conservation measures with individual paybacks can be misleading, the experts point out. For instance, caulking and weatherstripping windows can reduce the savings from storm windows. And increasing the efficiency of a furnace decreases the payback of adding attic insulation.
At Princeton and Lawrence Berkeley a number of new instruments are being developed to increase the accuracy and sophistication of audits such as this. However, the researches involved have been disappointed at the slowness with which their techniques have been put to use. "there are a handful of people who are using limited versions of our House Doctoring Program but no one is doing it all," says Dr. Dutt. As far as he and Dr. Dickinson know, no utilities are using these methods.