You should probably have more than one. How many and where do you put them?
John Drengenberg, consumer safety director at Underwriters Labs, says: "The recommendation for smoke alarms is to have one on every level of your home and also outside the sleeping area which is usually the hallway around the bedrooms. This gives you the loudest warning in the middle of the night and will certainly wake you up."
Mount those alarms high on walls or ceilings. Remember, smoke rises.
If you're installing new alarms on more than one floor, you might want to get the kind that are interconnected. They all go off no matter which one senses smoke.
"And this gives you the earliest possible warning because one in the basement might not go off as quickly as one on a second or even a third floor," Drengenberg says.
You don't need wires to interconnect alarms. You'll find a number of models on the market that use radio waves to do it.
If someone in your home is deaf or hard of hearing, consider installing an alarm that combines flashing lights and vibration with sound.
UL: Smoke Alarms
Consumer Product Safety Commission: Smoke Alarms