New construction standards require smoke detectors on each floor of the home (including the basement), inside each bedroom, and outside the bedrooms in the hallway. Large houses or areas with bedrooms remote from each other may require additional detectors to provide proper protection. All homes with fuel-burning heating systems, wood/coal/pellet stoves, and attached garages should have at least one carbon monoxide detector.
Many people choose to install combination smoke/carbon monoxide detectors. More important than location is to make sure that all detectors in the home are functional. Experts today recommend replacing all detectors over ten years old due to decreased sensitivity and reliability.
If you have specific questions relating to smoke or carbon monoxide detectors, contact the Building Department which has a helpful handout (PDF) and is available to answer any questions.