When choosing a smoke detector, there are several things to consider. Think about which areas of the house you want to protect, where fire would be most dangerous, how many you will need, etc.
Solon Fire Rescue recommends that every home have a smoke detector outside each sleeping area (inside as well if members of the household sleep with the door closed) and on every level of the home. The National Fire code requires a smoke detector inside each sleeping area for new construction. On floors without bedrooms, detectors should be installed in or near living areas, such as dens, living rooms or family rooms. Smoke detectors are not recommended for kitchens.
There are 2 basic types of smoke detectors:
1. Ionization detectors - Ionization detectors contain radioactive material that ionizes the air, making an electrical path. When smoke enters, the smoke molecules attach themselves to the ions. The change in electric current flow triggers the alarm. The radioactive material is called americium. It's a radioactive metallic element produced by bombardment of plutonium with high-energy neutrons. The amount is very small and not harmful.
2. Photo-electric detectors - These types of detectors contain a light source (usually a bulb) and a photocell, which is activated by light. Light from the bulb reflects off the smoke particles and is directed towards the photocell. The photocell then is activated to trigger the alarm.
The safest bet is to have both kinds and a combination detector with a battery back up. Be sure to check for a testing laboratory label on the detector. It means that samples of that particular model have been tested under operating conditions. Check to see if it is easy to maintain and clean. Be sure bulbs and batteries are easy to purchase and convenient to install.