Overview of the 2000 IECC

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.

For help in determining the climate zone in which your project is located, use the map below:

COMPLIANCE APPROACHES

A builder has a number of compliance options available in the Code. The main approaches are discussed here:

1. 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.
   
2. 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.
   
3. 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.

Chapter 6 sets forth energy efficient codes requirements for the design and construction of A-1 buildings as long as the glazing area does not exceed 15 percent of the gross area of exterior walls or meets the requirements set forth in Chapter 4 or Chapter 5. For the construction of A-2 buildings the codes requires the glazing area to be less than 25 percent of the gross area of the exterior walls. If the percentage of glazing area to gross exterior wall area is greater than the percentage allowed the building must comply with Chapter 4 or Chapter 5 of the 2000 IECC.