Replacing smoke or CO alarms? Check age, power and compatibility together

Separate a maintenance signal from the replacement date

A chirp may indicate a battery issue or a device that needs replacement. Follow the exact model's instructions rather than diagnosing it from a remembered beep pattern. If you are unsure whether a sound is an emergency warning, do not assume it is merely a low battery. Never disable an alarm while waiting for help.

The U.S. Fire Administration says smoke alarms need replacement 10 years from their manufacture date. A new battery does not restart that age. For CO and combination alarms, check the manufacturer's replacement instructions and end-of-life indications; do not assign every device the same service life. A failed or damaged unit needs attention before its age limit.

Make an inventory without taking anything down

Use receipts, manuals, installation records or existing label photos. For each location, record whether the device detects smoke, CO or both, its full model number, and any manufacture or replace-by date already documented. Keep those dates separate from the purchase date.

Take an intact front-view photo only from a safe floor position. If the model or date is hidden, leave identification to the visit. Do not remove an alarm, open wiring connections or climb on furniture to complete the list. Note inaccessible ceilings and any hearing-related alert needs when arranging help.

Match power and interconnection separately

Ask the assessor to identify battery-only versus hardwired power and the required backup arrangement. The presence of a battery does not establish that an alarm is battery-only. USFA advises that qualified electricians install hardwired smoke alarms and recommends checking local fire-marshal guidance on required alarm types.

Interconnection allows alarms to communicate, but the replacement must be approved for the devices that remain. Kidde warns that connecting unspecified equipment can cause nuisance alarms, failure to alarm or device damage. Have the installer check the exact model list and any specified adapter; a similar plug, mounting ring or brand name is not enough.

Include all connected alarms and accessories in that review, not just the unit making noise. Ask whether the proposal preserves the intended smoke and CO warning functions and whether additional units need replacement. Do not assume an app-connected product automatically joins the existing alarm network.

Agree on the replacement and the handover

Send Coast & Craft your city, inventory and accessible photos for scope review. Confirm who will perform any qualified electrical work before a visit is agreed. Keep the request specific:

• Which locations and exact models are included, and which devices will remain.
• Who supplies compatible units and any manufacturer-specified accessories.
• How protection will be maintained during the work and how the completed system will be checked.
• A handover with model records, replacement dates, manuals and maintenance guidance.