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Home Energy Magazine Online January/February 1998
TRENDS
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 http://www.engr.udayton.edu/weather.
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. |
|
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| 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 is a freelance writer and energy
consultant based in San Francisco.
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