Alterations, repairs, and additions: When alterations, repairs, or additions requiring a permit occur, or when one or more sleeping rooms are added or created in existing dwellings, the entire building shall be provided with smoke detectors located as required for new dwellings. The smoke detectors are not required to be interconnected unless other remodeling considerations require removal of the appropriate wall and ceiling coverings to facilitate concealed interconnected wiring.
Power Source: Required smoke detectors shall receive their primary power from the building wiring when such wiring is served from a commercial source and, when primary power is interrupted, shall receive power from a batter. Wiring shall be permanent and without a disconnecting switch other than those required for over current protection. Smoke detectors shall be battery operated when installed in buildings without commercial power.
There shall be a smoke detector in the furnace room.
Carbon Monoxide Detector: A carbon monoxide detector is also required by the 2012 International Residential Code. Only one is required in the home, preferably at a gas fired appliance, although not required at that exact location. A smoke/carbon monoxide detector combo unit can be used.