AGA criticismThe writers of the consensus document appear to have satisfied the many differing interests except for the American Gas Association (AGA), which bitterly criticized what it called the prejudicial treatment of its fuel in relation to electricity.
The new version is based on a “blended split” that bases efficiency requirements on a theoretical building by using 90% natural gas and 10% electricity, derived from Energy Information Administration data.
“We have tried hard to find a good basis for the numbers,” said Ron Jarnagin, standard committee chairman. “Does the average customer use the average rates for gas and electricity? No. But we’ve tried to represent what’s happening in the field.”
“ASHRAE based part of its standard on a formula that artificially inflates the cost of natural gas,” said Jim Ranfone, director, Building Energy Codes and Standards, AGA.
An earlier version used a dual-envelope section, which set different requirements for natural gas and electricity. This ignited a firestorm of controversy, since it singled out electrical resistance heating and required a more stringent envelope in some cases. This has been removed and the final version maintains a single set of building envelope requirements.
Using dual-fuel criteria “might invoke some legal liability because we’re singling out a technology,” said Jarnagin. “There are some anti-competitive aspects to it.”
Jarnagin added out that Standard 90 has never included separate envelope requirements for gas and electricity.
Fuel efficiencyAnother thorny issue is whether fuel efficiency should be measured at the fuels’ sources or on-site, where they are actually used. Natural gas has a low source cost since little energy is needed to produce and deliver it, in contrast to electricity, which is generated through the burning of other fuels.
Therefore, the revision would “promote the use of heating technologies that consume as much as two or three times the amount of energy as natural gas consumes,” said Ranfone.
“For a component or system in a building, we try to set efficiencies for that component or system at a level we feel will be energy conserving,” said Jarnagin. “One can argue that’s neither site- nor source-specific.”
The standard reflects the more efficient hvac and lighting equipment that has been developed during the decade. It is written in mandatory, enforceable language that can be adopted into building codes by federal, state, and local governments.
Designers planning buildings less than 25,000 sq ft and less than two stories will find the standard easier to use, said Jarnagin.