Wide variety of types available. Selection will depend on what you want to accomplish. Some feel a loud alarm at the point of entry will scare away the intruder. Others prefer a remote alarm located in a bedroom that will alert only the homeowner. Others prefer an outside alarm that will alert neighbors. Other kinds will sound an alarm and are connected directly to monitoring systems that will alert the police.
Simple alarms may consist of a door-locking device with a buzzer attached. When the device is tampered with or the door opened, the alarm sounds.
Many intrusion alarms are more elaborate and have twocomponents. A perimeter alarm detects intrusion at points of entry, such as door and windows. An area alarm detects motion inside a room.
Some types use low-voltage wire, similar to stereo speaker wire, to connect magnetic window and door sensors to a control panel.
Other types use radio transmitters at each door and window sensors to trigger an alarm at the control panel.
Alarm sounds when the window or door opens.
Alarm systems designed for d-i-y installation are frequently battery powered, so ease in testing the batteries can be an important feature. Some systems sound a warning when the batteries are low.
Hard-wired systems may have a button on the control panel that checks the entire system.
Uses either ultrasonic waves or microwaves to detect motion. When it detects motion, it triggers an alarm.
Generally plugs into a standard electrical outlet, so they’re easy to install.
Ultrasonic detector waves only go as far as the wall of the room, while microwaves penetrate walls and windows.
Some ultrasonic alarms use a narrow sonic beam that must be bounced off a hard surface. Here, the intruder must break the beam to be detected.
Other ultrasonic alarms use a wide beam that fills the room and detects motion anywhere in the trap zone.
The most important consideration with this type of alarm is avoiding false alarms. These can be caused by air conditioners or drapery moving above a hot air register. Better systems have built in circuitry that does not respond to these types of signals.
Some systems have extra repeater alarms or satellites. These can be plugged in anywhere in the home to add extra noise and relay the warning to remote rooms.
Measures the changes in electric current caused by invisible particles ionized in the heat of combustion.
Transforms air inside the detector into a conductor of electric current. When smoke enters the detector and impedes the flow of current, the alarm sounds.
Responds particularly well to the smoke caused by a flaming fire.
Requires little power and is effectively powered by household batteries.
Slower to respond to a smoldering fire.
Detectors are required to emit a low warning when batteries are weak.
Uses a small lamp adjusted to direct a narrow light beam across the detection chamber. Smoke entering the chamber scatters this light beam, causing it to hit a sensor and set off the alarm.
Usually more sensitive to smoke from a slow, smoldering fire than an ionization detector, but reacts less quickly to flaming fires.
Available in both battery-operated and plug-in versions.
Detects carbon monoxide, a colorless, odorless, deadly gas that poses a potentially deadly health risk to people.
Measures the amount of carbon monoxide over time and sounds an alarm before people would experience symptoms.
Operates on batteries or can be plugged in.
Some models provide a running digital readout of CO levels.
Hard-wired or plug-in models typically use some type of solid-state sensor, which purges itself and resamples the air periodically. That cycle increases the power demand.
Battery-powered detectors typically use a passive sensor. They will operate even in case of a power failure.
Available in combination units that have CO and smoke detectors in the same unit.
Detects radon, a colorless, odorless, radioactive gas formed wherever there is uranium, an element present throughout the crust of the earth. It poses little risk if it makes its way to open air, but if it seeps into a house, it can collect in hazardous concentrations.
This detector consists of a small sheet of plastic. Alpha particles that strike the plastic cause microscopic pockmarks.
After an exposure period, users mail the detector to a lab. The lab’s count of the pockmarks gives a direct measure of the mean radon concentration.
Another type uses activated-charcoal granules, which trap radon gas. After an exposure time, the container is resealed and shipped back to a lab for analysis.
Has a locking button on the inside knob but no key device on the outside knob.
Can be either a knob or a lever.
In an emergency, the lock can be opened from the outside by inserting a narrow object through the small hole in the outside knob and either depressing or turning the locking mechanism inside, depending on the type of lock.
Available in a wide variety of styles and finishes.
Called “dead” because there are no springs to operate the bolt. It is only operated manually with a key or a thumb turn from the inside.
The bolt locks the door to the frame and helps prevent someone from prying the door open.
The throw is the length the bolt is extended from the lock housing.The industry standard is a 1” throw.
Locks are designed to fit specific size holes and backsets. Backset refers to the distance between the edge of the door and the center of the handle.
A single-cylinder deadbolt is operated with a key from the outside and with a turn button on the inside. It is used mostly with solid metal or wood doors.
A double-cylinder deadbolt is operated with a key on both the inside and outside. It is best used on a door with glass in or around them as the style prevents someone from breaking the glass, reaching in and unlocking the door.
Double-cylinder deadbolts can pose a danger during an emergency. If the key is missing or not readily available, people could be trapped inside a locked house. In some areas, codes may not permit this style of deadbolt.
Consists of a flat, rectangular box that fits into a recess in the door from its edge. Also includes two faceplates that include the knobs and keyholes.
Available in right- or left-handed styles.
Has a pin tumbler locking mechanism in a cylinder.
Latch operates from either side except when the outside knob is locked.
Deadbolt operates by a turn of the inside knob.
A key from the outside operates both the deadbolt and latchbolt.
Used on many types of doors, from heavy entrance doors to apartment buildings and residential doors.
Used primarily by large commercial firms.
Provides maximum protection for bicycles, gates, etc.
Fits over the trigger housing of guns to prevent firing of the weapon.
Used to secure standing trailers by rendering the towing device inoperable.
Wide variety of types available. Selection will depend on what you want to accomplish. Some feel a loud alarm at the point of entry will scare away the intruder. Others prefer a remote alarm located in a bedroom that will alert only the homeowner. Others prefer an outside alarm that will alert neighbors. Other kinds will sound an alarm and are connected directly to monitoring systems that will alert the police.
Some types use low-voltage wire, similar to stereo speaker wire, to connect magnetic window and door sensors to a control panel.
Uses either ultrasonic waves or microwaves to detect motion. When it detects motion, it triggers an alarm.
Measures the changes in electric current caused by invisible particles ionized in the heat of combustion.
Uses a small lamp adjusted to direct a narrow light beam across the detection chamber. Smoke entering the chamber scatters this light beam, causing it to hit a sensor and set off the alarm.
Uses the combination of a lock and cable to lock and secure objects in a variety of applications.
Detects carbon monoxide, a colorless, odorless, deadly gas that poses a potentially deadly health risk to people.
Detects radon, a colorless, odorless, radioactive gas formed wherever there is uranium, an element present throughout the crust of the earth. It poses little risk if it makes its way to open air, but if it seeps into a house, it can collect in hazardous concentrations.
Plugs into a standard outlet.
Extinguishes Class B and C fires.
Some types extinguish only Class B and C fires.
Extinguishes Class A and B fires.
Protects valuables and documents exposed to fire.
Used to escape from an upper story window.
For advanced home security and convenience.
An interior lockset.
Used only for decoration or applications that do not need a latch.
Two doorknobs that can be locked from both the inside and the outside.
Provides maximum security on a door.
Squarish in shape and mounted on the surface of the inside of the door.
Usually an entry set that combines a lockset with a deadbolt, the deadbolt is located just above the knob or handle. Can be a one- or two-piece unit.
Consists of a flat, rectangular box that fits into a recess in the door from its edge. Also includes two faceplates that include the knobs and keyholes.
Installed on the inside surface of the door.
An interior lockset used inside the home in hallways or closets between rooms where privacy is not important.
Consists of a metal hinge and an anchoring bolt so locks can be secured to gates, sheds and garages.
A sliding lock mechanism used to provide security for average weight doors and windows.
The metal plate the latch slides into on the doorjamb or frame.
Used on in-opening doors.
User must dial a combination to open the lock.
Provides maximum security for valuables.
Offers many key changes by replacing the cylinder.