Types

• Most smoke alarms use either a photoelectric sensor, which reacts when smoke blocks light, or an ionization sensor that detects changes in the air's electrical current. Alarms may run off of battery power or electricity.
  
  

Cold Weather Fires

• Firefighters advise changing a smoke alarm's batteries when Daylight Savings Time ends. House fires increase during the winter months because of the use of space heaters or furnaces along with increased holiday cooking and entertaining.
  
  

Weather Sensitivity

• Some alarms may go off when extreme cold weather or temperature changes create condensation on the unit's sensor, according to the Firex website.
  
  

Alternatives

• Heat detectors, which respond to sudden changes in temperature instead of smoke, may prove more accurate and useful in cold areas such as garages.
  
  

Maintenance

• Smoke detectors will not work correctly without fresh batteries. Most smoke alarms "chirp" to warn of a low battery. Cleaning the unit with a vacuum hose can eliminate any dust that might affect proper function.