Overview of the 2000 IECC
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SCOPE OF THE IECC
The IECC covers new construction, additions, remodeling, window replacement,
and repairs of specified buildings. The Code applies to what are called Type
A-1 and A-2 residential buildings. Type A-1 buildings are detached one- and
two-family dwellings. Type A-2 buildings are those containing three or more
dwelling units that are three stories or less in height above grade. Commercial
buildings are covered as well. A building is considered to be commercial when
it is over three stories in height above grade or when it is below three stories
and is not a residential building.
The Code provisions are intended to ensure the design of energy efficient building
envelopes. They also address the energy efficiency of elements that do not affect
the building envelope, such as mechanical, water heating, electrical, and lighting
equipment. The envelope requirements focus on insulation requirements for ceilings,
walls, and floors and on thermal conductance of windows and doors.
CLIMATE ZONES
The Code requirements vary by region. The regions are determined based on the
climate and, hence, are called "climate zones." Each county in the
country is sorted into one of nineteen climate zones.
COMPLIANCE APPROACHES
A builder has a number of compliance options available in the Code. The main
approaches are discussed here:
- The Simplified Approach (Chapter 6)
The requirements in Chapter 6 are not new to the Code. Instead, it provides
a simplified form of the prescriptive requirements already found in the Code
for walls, ceilings, floors, windows and doors.
- The Component Performance Approach (Chapter 5)
Contrary to the approach used in Chapter 4, in which the energy use of the
whole house is examined, Chapter 5 provides builders with various ways to
comply with the thermal requirements of the Code by examining the performance
of various components. Using one approach in Chapter 5, the builder shows
compliance by demonstrating that the performance of individual components
meets specified heating and cooling criteria. Another approach allows builders
to show compliance when the performance of the total building envelope conforms
to the Code. Builders can also comply by analyzing the acceptable practice
of each individual component under Code provisions. Finally, a builder may
show compliance by matching the building components to prescribed standards
for each individual component. Chapter 5 also spells out requirements for
mechanical equipment, HVAC systems, water heaters, swimming pools, pump operation,
pipe insulation, water conservation, and electrical and lighting systems.
- The Systems Analysis Approach (Chapter 4)
Chapter 4 of the IECC® allows compliance by ensuring that the total energy
use of the building meets the Code requirements when all of its various systems
are included in the analysis. This chapter also gives the builder some leeway
in terms of energy consumption when renewable energy sources are used.
ADDITIONS, REMODELING, AND REPLACEMENT WINDOWS
As stated above, the 2000 IECC also applies to additions, remodeling, window
replacement, and repairs of residential buildings. Existing installations are
exempted, as are portions of buildings not altered when additions, remodeling,
window replacement, or repairs take place. Historic residences are also exempted
from meeting the requirements of the Code. In addition, the prescriptive path
section of Chapter 5 gives some specific provisions for additions to buildings
and replacement of windows, located in Section 502.2.5. The Table below summarizes
the prescriptive paths in a chart form and some additional requirements are
contained in the following bullets:
- Section 502.2.5 may be used for an addition only when the floor area is
less than 500 square feet of conditioned space.
- The total area of fenestration products for an addition should not exceed
40% of the gross wall and roof area of the addition.
- Far an addition, the U-factor and SHGC values needed for comparison to the
requirements in the Table are area-weighted averages of all the fenestration
products for the addition.
- The 2003 version of the IECC requires that conditioned sunroom additions
maintain thermal isolation, not be used as kitchens or bedrooms, and must
have a separate heating or cooling system or be thermostatically controlled
as a separate zone of the existing system.
For help in determining the climate zone in which your project is located,
use the map below: