Smoke and CO alarm installation

Why working alarms matter

The NFPA states that "roughly three out of five fire deaths happen in homes with either no smoke alarms or no working smoke alarms" and that "the risk of dying in a home fire is cut in half in homes with working smoke alarms."

Where alarms go

The U.S. Fire Administration recommends "installing smoke alarms in every bedroom, outside each separate sleeping area, and on every level of a home." It also advises choosing "interconnected smoke alarms so that when one sounds, they all sound." Carbon monoxide alarms belong outside sleeping areas and on each level, especially in homes with gas appliances, fireplaces or attached garages.

Replacing hardwired alarms

Hardwired alarms connect to house power with a plug-in harness and usually have a backup battery. Many are interconnected by a third wire. Replacements should be compatible with the existing interconnect so all alarms sound together.

Some brands make adapters for older harnesses. We swap the alarms, connect the harnesses, test each unit and confirm they all sound together.

Battery and sealed alarms

Where there is no wiring, sealed battery alarms can be mounted on ceilings or high on walls. Some sealed units are designed to last their full life without battery changes. Combination smoke and CO alarms reduce the number of devices.

Chirping

A chirp usually means a low battery or an alarm reaching the end of its life. Alarms carry a manufacture date on the back; makers list when to replace them. Changing the battery will not stop an end-of-life chirp.

Scope

See the full list of electrical work we take on.

Adding hardwired alarms where there is no wiring requires new circuits or wiring and is outside what we do; sealed battery units are an alternative.

Alarm types

The U.S. Fire Administration describes ionization alarms, photoelectric alarms and dual-sensor alarms, which "contain both ionization and photoelectric smoke sensors." It also notes there are alarms for people with hearing loss that use strobe lights or vibration. Choosing the right type for each room and the people in the home matters.

Placement details

Mount alarms on ceilings or high on walls, following the maker's instructions. Avoid locations right next to kitchens and bathrooms where steam or cooking set off nuisance alarms, near vents that blow smoke away, and in dead-air corners. CO alarms follow their own placement guidance in the manual.

Rental properties

Landlords should keep alarms working and replace them on schedule. A tenant can let us in to replace alarms throughout a unit.

Testing after install

We press the test button on each alarm, and on interconnected systems confirm that all alarms sound when one is tested. We note the install date on the alarm.

What to send

Photos of the existing alarms, the back label showing the brand and date if you can remove one, and a list of rooms.

When to replace alarms

Alarms do not last forever. The manufacture date on the back and the maker's instructions tell you when to replace them. A house full of alarms of different ages is common; replacing them together keeps them on the same schedule and ensures interconnection works. When you move into a home, check the dates on every alarm.

More questions

Can you remove alarms that keep chirping? We replace them; removing alarms without replacement leaves the home unprotected.

Can I have a combination alarm in the hallway? Yes, a combination smoke and CO alarm works well outside bedrooms.

Carbon monoxide basics

Carbon monoxide is a colorless, odorless gas from burning fuel. Gas water heaters, furnaces, stoves, fireplaces and cars in attached garages can produce it. CO alarms are the only way to detect it.

If a CO alarm sounds, move everyone outside and call 911 or the gas company. Have fuel-burning appliances checked regularly.

Alarms and cooking

Photoelectric alarms are less prone to nuisance alarms from cooking than ionization alarms in many cases. Placement away from the stove helps.

Hearing and accessibility

For household members who are deaf or hard of hearing, alarms with strobe lights or bed shakers alert them when an alarm sounds. These add to standard alarms. Place strobes where they can be seen from bed, and test them with everyone in the household so they recognize the signal.

More questions

Do alarms expire even if they work? Yes. Follow the maker's replacement date.

Nuisance alarms

Alarms placed too close to a kitchen or a steamy bathroom go off while you cook or shower. Moving the unit a few feet, or using a photoelectric model near the kitchen, usually ends the false alarms without removing protection.

Chirping at night

A low battery chirp often starts in the early morning hours when the house cools. Replacing every battery at once saves you from chasing chirps room to room. We bring spares when we visit.

Ten-year sealed units

Sealed alarms with a built-in battery skip the yearly battery swap. When one reaches its end-of-life signal, the whole unit gets replaced.

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