Ask House Spouse · Safety & Prevention · Smoke & CO Detectors
How often should smoke and CO detectors be replaced?
Short answer
Smoke detectors: replace the whole unit every 10 years (the sensor degrades regardless of battery). CO detectors: 5–7 years depending on brand — check the sticker on the back for the exact replace-by date. If either detector is over its date, replace it now, then set a calendar reminder for the next one.
Placement in WA homes
Smoke detectors on every level, in every bedroom, and outside every sleeping area. CO detectors within 15 feet of every sleeping area and on every level with any combustion appliance (gas furnace, gas water heater, gas fireplace, attached garage).
Hardwired vs. battery
Homes built after ~1993 in WA are typically hardwired with battery backup — replace the batteries once a year regardless. Older homes may be battery-only; upgrade to 10-year-sealed-lithium units so you're not chasing a chirp at 2 a.m.
Combo units
Combined smoke+CO detectors are practical for interior sleeping-area coverage, but keep dedicated CO detectors near combustion appliances. On assessments we log every detector's replace-by date so you know what needs to change and when.
What we see on Home Health Assessments
Based on real experience across Snohomish and King County, safety & prevention issues like this are among the ones homeowners most often miss until they become expensive. Our Home Health Assessment catches them early — while they're still a maintenance item, not a repair.
How the Home Health Assessment worksServices we'd bring to this job
Related questions
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What is an AFCI breaker and do I need one?
An AFCI (arc-fault circuit interrupter) breaker detects the tiny electrical arcs that precede electrical fires — the kind that happen inside walls where you can't see them. Modern electrical code requires them on most living-space circuits. Homes built before ~2008 typically don't have them; retrofit is a licensed-electrician job worth doing.
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How often should I clean my dryer vent?
Every year, minimum — and every 6 months if you dry more than 5 loads a week or have a long vent run. Clogged dryer vents are the #1 cause of house fires attributed to appliances (per the U.S. Fire Administration), and they double your dryer's electricity use before they get to that point. Both problems, one $150 cleaning solves.