How many smoke detectors should I have in my home? Where should I put my Carbon Monoxide Detector?



My house is 20 years old and it is a 1 1/2 story with a full basement. The gas furnace/water heaters are in the basement. Access to the basement is through the interior of the house and it's walk-out. I'm planning on totally replacing the smoke detectors, they are not hard wired. [...]