Smoke Detector Installation Cost in Seattle

How Much Does Smoke Detector Installation Cost?

Smoke detectors save lives, and Washington State has specific requirements about where they go and what type you need. Here is what homeowners in Seattle, Renton, Newcastle, and Bellevue can expect to pay for professional smoke detector installation.

Installation Pricing

• Replace existing hardwired detector: $75–$125 per unit. Direct swap, takes about 15 minutes each.
• New hardwired detector (new wiring): $150–$250 per unit. Requires running wire from the panel or daisy-chaining from another detector.
• Combination smoke/CO detector: $100–$175 per unit installed. Required in homes with gas appliances or attached garages.
• Whole home package (6 to 8 units): $500–$1,000 for replacement of all detectors with new interconnected units.

Washington State Requirements

Washington law requires smoke detectors in every bedroom, outside each sleeping area, and on every level of the home including the basement. Key requirements:

• Hardwired with battery backup in new construction and remodels
• All detectors must be interconnected so when one sounds, they all sound
• Carbon monoxide detectors required in homes with fuel burning appliances or attached garages
• Smoke detectors must be replaced every 10 years regardless of condition

When to Replace Your Smoke Detectors

Most homeowners do not realize smoke detectors expire. If yours are more than 10 years old, the sensors degrade and may not activate in a fire. Check the manufacturing date on the back of each unit. If there is no date or it is older than 2016, it is time to replace them.

Same Day Service Available

Smoke detector replacements are quick jobs. We can typically replace all detectors in a home in under two hours. Same day and next day scheduling available throughout King County.

Had all eight smoke detectors in our home replaced with new combination smoke and CO units. The electrician was done in about 90 minutes. Peace of mind knowing our family is protected.

Renton Highlands homeowner, March 2026

Get a Smoke Detector Installation Quote

Call 425-210-4791 or request a free estimate online. We serve Renton, Newcastle, Bellevue, and all of King County.