• Motion light with sensordoor and motion detector image by Larry Roberg from Fotolia.com
  
  A variety of exterior lights are sold with sensors to trigger them. The best exterior sensor light is dependent on the application and user. For example, you would not want to use a motion sensing light where cars pass in front of it all night. Of the three types of exterior sensor lights, at least one will be best for your application, desires and budget.
  
  

Heat Sensing

• Lights with heat sensors will not activate from motion. The sensors are triggered by heat, human body heat to be more specific. These types of sensors will keep small animals and tree branches from turning your lights on all the time.
  
  

Motion Sensing

• Motion sensors detect motion in front of them and, in turn, trigger the light. The biggest disadvantage is their tendency to be triggered by nonsecurity threats, such as small animals and passing cars. Motion sensors are typically less expensive than heat sensing lights.
  
  

Light Sensing

• Light sensing security lights have a photovoltaic cell. They come on when the sun goes down and go off as the sun rises. These lights possibly won't help to alert you to a presence as they will be on all night. They are the least expensive to purchase but the most expensive to operate, which is based on their remaining lit all night, using more energy and requiring more frequent bulb changes.