There are three approaches to make an addition comply with the energy code:
- The addition as defined above meets all code requirements. This approach does not require that the original portion of the building meet code requirements.
- If the building combined with the addition complies with the code, the addition will also comply, regardless of whether the addition complies alone. For example, a sunroom that does not comply with the code is added to a house. If the entire house (with the sunroom) complies, the addition also complies.
- In the 2000 and 2003 International Energy Conservation Code, additions less than 500ft2 (46.5m2) of conditioned floor area may meet the prescriptive envelope requirements in the table. To use the table, the total area of windows, doors, and skylights cannot exceed 40% of the gross wall and roof area of the addition.
This document describes how to use REScheck™ to comply with approach #1.