What is California Title 24
Energy efficiency reduced energy costs, increases reliability and availability
of electricity, and reduces impacts to the environment. Therefore, energy efficiency standards are important and necessary
for California's energy future.
The 2005 Residential and Non-Residential
Standards are expected to reduce the electricity usage growth by 478 gigawatt-hours per year and reduce gas usage growth by
8.8 million therms per year.
When Are Radiant
Barriers REQUIRED Under Title 24 Standards?
There
are two approaches to complying with the 2005 Residential and Non-Residential Standards. The prescriptive approach
is the simplest where each individual component of the building must meet a prescribed minimum energy requirement. A
home must meet all of the requirements of the alternative package for its climate region. It is the least flexible yet
simplest approach to comply with.
The performance
method provides the most flexibility but it also requires the most effort. To comply with the performance method,
the builder uses an approved computer model to calculate the energy budget for the building.
Radiant barriers are required for the following climate zones with significant cooling loads when using the prescriptive approach:
Zone 2,
Zone 4, and
Zones 8 through 15
Three Allowed Methods of Installation for Radiant Barriers
The California Energy Code mandates radiant barriers be installed in one of the
three following methods:
Stapled to the underside of the
roof decking,
Draped over the truss cords or rafters,
Stapled to the inside of roof rafters, or
Stapled to the bottom of the truss cords or rafters.
There must be a 1 1/2 inch air space below the roof deck and an air space of 3 1/2 inches from the insulation
on the roof decking to allow ventilation air to flow between the roof decking and top surface of the radiant barrier.
A minimum of 6 inches (measured horizontally) shoudl be left at the roof peak to allow hot air to excape from the air space
between the roof decking and the top surface of the radiant barrier.
Radiant
barriers must be installed on gable ends as well
