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


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Home Energy Magazine Online January/February 1998


Title 24: The Next Step

Daily Temperature Data at Your Fingertips

Figure 1. Daily weather data for 159 cities are available free on this University of Dayton Web site.
Did that wall insulation cause the drop in utility bills, or was it just a milder winter? It's a hassle to assemble data for weather-normalization. Besides, it's hard to find this month's data without measuring for yourself. That hassle has been greatly reduced, thanks to a new Web site. You can now download average daily temperature data for 159 U.S. cities. Best of all, the data are updated daily, so you can get yesterday's average temperature just as easily as the temperature for the same day last year. The files conveniently download in a format that fits into spreadsheets and some canned energy analysis programs. 

The site's Web address is

Another reason to bookmark the site is that it will soon contain software to perform energy savings calculations. Thanks to support from EPA, the University of Dayton has created sophisticated energy analysis software to estimate savings from retrofits in a range of situations.

Evolution of building codes.
California's energy standards for new buildings, known as Title 24, are being revised to make building energy savings more reliable. In early 1997, the California Energy Commission (CEC) staff brought together a diverse group to work out changes in the code. The CEC has now approved the changes, and the new version will be published in July 1998 and go into effect on January 1, 1999.

From the outset, commissioners sought changes that would not demand more extensive conservation measures or result in additional costs to builders. Thus the new standards aim at eliminating ineffective measures, making the code easier to work with, and placing emphasis on measures with potential for long-term energy savings, such as windows.

The revision process was an open one, according to CEC Project Manager Dee Anne Ross. By getting our staff together with representatives of the building industry, and groups representing homeowners' concerns, like NRDC [Natural Resources Defense Council, a nonprofit organization], we hope to avoid last-minute complaints. Another nonprofit that represented the public interest at the hearings was the California Association of Building Energy Consultants.

Consultant Ken Nittler, coauthor of the popular Micropas Title 24 compliance software, participated in the proceedings. He confirms that it was an open process, but sees room for improvement. At times I wished there were more public interest advocates present to adequately represent the need for energy efficiency and well-built homes, he says.

The CEC estimates that Title 24 has resulted in more than $11 billion in energy savings over the last two decades. The energy codes are updated every three years, in conjunction with updates of other codes relevant to the building industry.

What's New A new window labeling requirement is a simple change that both Ross and Nittler believe has good potential for improving building efficiency. Solar heat gain coefficient (SHGC) labels will be required for windows, along with the U-value label already required. This will allow for direct comparison of the windows' capacity to filter incoming solar radiation.

Low-emissivity windows can do amazing things, says Nittler, from increasing comfort to reducing cooling and heating loads--even decreasing fading from UV. But the market for these products is not fully developed at this point. The rating system will alert buyers to each window's various features and give them a yardstick for deciding on the right product for their application.

Nittler hopes that mandatory labeling will transform the market by giving consumers enough information to enable them to demand good products. This would give manufacturers the financial incentive to produce better windows. But he cautions that while strategies to encourage market transformation help, they cannot replace mandatory minimum requirements. Energy Star and other voluntary compliance programs work well in some sectors, but without established minimum requirements, too many builders would ignore energy-efficient design issues, he says.

Another change is the inclusion of more specific instruction on how to install ductwork. In 1996, energy consultant Sharon Block surveyed new buildings. In diagnostic checks of heating and air conditioning systems, she found missing vapor barriers, constrictive layouts, and incomplete seals to be typical. The code changes address workmanship issues.

Several code changes were attempts to eliminate standards like these that are no longer appropriate. Both water heater blankets and roller shades are currently credits in the calculation methodology used to test compliance. Water heater blankets are much less effective now that water heaters themselves are better insulated. The blankets create problems as well, by covering up warning labels and making it difficult to strap tanks for earthquake safety. As soon as the code changes take effect, blankets will cease to count toward building efficiency. Similarly, roller shades are currently counted as a method to keep out unwanted solar gain. But their effectiveness depends on residents, who often remove them rather than drawing them each day. The credit for roller shades will be phased out over three years.

Title 24 requires builders to use efficient lighting in kitchens and bathrooms. The new standards give them alternatives--to satisfy the code for a bathroom, for example, they must use a high efficiency lamp unless they make up for it by having high efficiency lamps in all outdoor lights and in the garage or utility room.

In commercial buildings, lighting standards have been tightened to reflect the increased availability of efficient products like electronic ballasts with T-8 lamps, LED exit signs, and compact fluorescent downlights.

Construction Liability Construction defect litigation is on the rise (see Energy-Conscious Construction: Litigation Insurance? HE Nov/Dec '97, p. 31). The new codes may reduce liability by requiring better duct installation practices which produce more functional HVAC systems, and by eliminating credits for measures of dubious effectiveness. At the same time, the standards continue to stress a builder's responsibility to provide the first occupant of a home with energy documentation and an installation certificate, proof that the home complies with the energy efficiency standards.

The threat of litigation may be slowly motivating more builders to learn about the energy code. As Block's survey points out, increased awareness does not necessarily equate with compliance in the field, but it is certainly an essential step.

Educating builders is important, but other efforts are needed, too, explains Block, who chairs the California Association of Building Energy Consultants (CABEC). Code enforcement needs strengthening, and consumers need to be educated about what features make for a better building. CABEC was deeply involved in the formation of the new efficiency standards.

Just as SHGC labeling is expected to lead to a market transformation in the production and use of windows, a home energy rating system (HERS) may be the best strategy for inducing a market transformation in the production and use of efficient buildings themselves. The CEC has conducted proceedings on the development of a home energy rating system for several years.

The inclusive process used in this round of amendments to Title 24 set a good precedent for the next round. Still, while adjusting some features of Title 24 will increase the reliability of savings from the code, major improvements in its effectiveness may have to wait until a HERS program gives consumers the knowledge to demand higher efficiency and programs are in place to educate consumers, inspectors, and builders.

--Doug Johnson
Doug Johnson is a freelance writer and energy consultant based in San Francisco.



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