Buying a detector involves some key decisions

Ionization detectors
The most common and cheapest smoke detectors, they can be found in about 90 percent of US homes. These detectors meet Underwriters Laboratories standards and respond quickly to high-flaming fires. But some research shows they are slow to react to smoky blazes. They typically cost no more than $10.

Photoelectric detectors
Some experts, including the Boston Fire Department's deputy chief, say this is the preferred detector for a modern home because it has a sensor that is quicker to respond to smoldering fires, which are the most common when synthetic materials burn. This type of detector typically costs up to $60.

Dual ionization and photoelectric detectors
These alarm systems, which are recommended by the US Fire Administration, have both ionization and photoelectric technologies. This combination allows them to respond quickly to both smoky and flaming fires. These models typically cost from $25 to $75.

Wireless networks
This new technology allows detectors to be wirelessly connected so that when one senses a fire it almost simultaneously triggers all the alarms in the house. Prices for detectors with this technology begin at about $40.

Detectors connected to fire departments
Devices that alert a fire department when they go off can be among the most expensive, but nearly all insurance companies offer the greatest discounts to those who choose to install such technology in their homes. These systems, which often include burglar alarms, can cost as much as $1,000, not including installation fees.

Installation
Smoke detectors should be mounted on either a wall or a ceiling, depending on the model. The general rule is there should be a working detector on each floor of a home, including the basement. Some experts suggest installing detectors close to the kitchen and bathrooms.