Every home needs to be protected against smoke, fire and carbon monoxide. Smoke alarms and carbon monoxide detectors are the best way to provide that protection. When properly installed and maintained, both devices will alert the entire household early enough to allow for a quick response.
Smoke, fire and carbon monoxide all require specific types of alarms and detectors:
Photoelectric smoke alarms detect slow, smoldering, smoky fires.
Ionization smoke alarms detect flaming, fast-moving fires.
Heat (temperature-sensing) alarms detect significant changes in temperature.
Carbon monoxide (CO) detectors can sense this odorless gas, which is toxic to humans.
All homes should be equipped with all four types of protection. Dual-sensor smoke alarms can detect both smoke and flaming fires, but they can’t detect carbon monoxide. Some CO detectors can also alert you to one, and only one, type of fire risk. In other words, one or two types of alarm, no matter how many of them you have, will not provide full protection.
Smoke alarms can be battery operated (wireless) or hard-wired (tied into the household electrical system). Both types have their pros and cons. Battery-operated alarms are easy to install, and they will function even if the power goes out in your house. Hard-wired alarms do not depend on batteries to function. They will only operate during a power outage, however, if they are equipped with battery backup and the batteries are in good shape. Hard-wired systems with battery backups are usually required in new construction.
Though both types of alarms cost about the same, a hard-wired device will require an electrician for installation. That will probably add $200 or more to the cost of each alarm. A hard-wired alarm with battery backup is the safest choice, but battery-operated alarms function just as well as long as the batteries are kept fresh.
You can also buy plug-in alarms with battery backups. These are suitable for small areas.
Heat alarms are an overlooked type of fire protection. They are activated by a significant rise in temperature, and nothing more. Thus, they cannot be triggered into false alarms by harmless smoke. They aren't going to offer an early warning of a slow, smoldering fire, and thus are no substitute for standard smoke alarms. But they can be ideal for use in garages, basements, attics, and furnace or boiler rooms.
To provide maximum protection, your house should have multiple alarms. But in the event that one of them detected a problem, you want to know that all of them to kick into operation alerting everyone in the house of impending danger. If a fire is smoldering or flaming in the garage in the middle of the night, for example, you would want an alarm going off upstairs.
Hard-wired systems can provide this communication between separate alarms. Battery-operated, wireless alarm systems are also available that can work in tandem, but only if each alarm is from the same manufacturer. Hard-wired alarms from different manufacturers can alert each other with the use of special adapters.
What To Look For
Here are some things to keep in mind when shopping for smoke alarms and carbon monoxide detectors:
Dual-sensor smoke alarms are the best choice in most, but not all, cases. Steam from bathrooms and kitchens can set off ionization alarms, so consider using photoelectric units in these locations.
Choose carbon monoxide detectors and smoke alarms that can interconnect (i.e., communicate with each other).
To alert someone with a hearing disability, install alarms that vibrate or use flashing lights.
Choose alarms with a “hush” or “mute” button to quickly silence false alarms.
Consider buying a carbon monoxide detector with a digital display that records actual CO levels.
Where To Place Smoke Alarms and Carbon Monoxide Detectors
Always follow the manufacturer’s advice on installation and exact location. Here are some general guidelines:
Living areas: Install one dual-sensor smoke alarm and one CO detector.
Kitchen: Install a photoelectric smoke alarm near, but not directly in, the kitchen.
Bedrooms: Install dual-sensor smoke alarms in each bedroom and in the hallway. Also install a CO detector in the hallway.
Garage: Install a dual-sensor smoke alarm or (especially if false alarms are a problem) a heat alarm. If you park your car in the garage, do not install a CO detector, as the car exhaust will trigger repeated false alarms.
Attic: Install a dual-sensor smoke alarm and/or a heat alarm.
Basement: Install a CO detector at least 20 feet from any fuel-burning device (water heater, furnace, etc.). Install a dual-sensor smoke alarm in or near the stairwell. A heat alarm may be preferred if false alarms are a problem.
Windows, doors and vents: Keep all alarms away from them, as drafts and breezes can affect operation.
Care and Replacement
Batteries should be replaced every year. Consider designating a holiday for this task to help you remember. If the alarm starts chirping, the batteries should be replaced.
Smoke alarms should be replaced every 8-10 years. Carbon monoxide detectors should be replaced every 5 years.
Supplement smoke alarms and carbon monoxide detectors with one of more fire extinguishers. See How To Choose a Fire Extinguisher for Your Home.