In zones 3 to 8, open-combustion appliances fed by combustion air ducts sit outside the envelope or in a sealed, insulated room with a gasketed door; the air duct is R-8 through conditioned space. Direct-vent appliances are exempt.
More Efficient Thermal Distribution System Options
Distribution credits: ductless or hydronic inside, all ducts and equipment inside, at least 80 percent inside, low duct leakage (2.0 or 1.75 cfm/100 sq ft), or room airflow balanced within 20 percent.
Searches all 4,276 IRC 2024 sections, 5,532 IBC 2024 sections and defined terms (Chapters 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33 so far) and each city's local rules as they are added. Section numbers and titles from the International Residential Code and International Building Code, 2024 editions, copyrighted by the International Code Council; the IRC's electrical chapters (34 to 43) follow NFPA 70, the National Electrical Code. Requirements are summarized in our words (IRC Chapters 3 to 43, IBC Chapters 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33); read the full text at the link on each result. Local values come from each city's published documents.
Check your plans against these codes
Start an application and get every flag with its section and fix.