The cost to install smoke detectors depends on whether you’re replacing existing units, adding new detectors in existing wired locations, or running new wiring to previously unprotected areas. A simple hardwired detector swap — removing an old unit and connecting a new one to the existing wire harness — is a quick job that costs far less than installing detectors in locations that have never had wiring. Done! provides upfront pricing for smoke detector installation so you know the cost before any work begins.

What Affects Smoke Detector Installation Cost

The biggest cost driver is whether electrical infrastructure already exists. Hardwired smoke detectors connect to a 120-volt circuit and are interconnected — when one alarms, all alarms. If that circuit already runs to the detector location (as it does when you’re simply replacing an aging unit), the installation is primarily labor for a quick swap. If you’re adding detectors to rooms that were never wired — common in older Denver homes, additions, and converted spaces — the electrician needs to run new wire, which involves more time, materials, and potentially some drywall work.

  • Straightforward replacement — existing wiring, same location, compatible voltage: lowest cost, often completed in under an hour for multiple units
  • New location, accessible attic or crawl space for wire routing — moderate cost; attic access makes wire runs cleaner and faster
  • New location requiring in-wall wire fishing — higher labor cost; running wire through finished walls without attic access takes more time and skill
  • Adding an entirely new circuit — if the existing smoke detector circuit is at capacity or doesn’t reach the new locations, a new circuit from the panel adds cost but ensures proper interconnection

Equipment Choices and Their Cost Impact

Not all smoke detectors are the same price. Standard single-function hardwired ionization or photoelectric detectors are the most economical. Combination smoke and carbon monoxide detectors cost more but provide dual protection from one device — relevant in Colorado where CO poisoning risk is elevated due to the prevalence of gas appliances and the altitude’s effect on combustion. Smart detectors that integrate with home Wi-Fi and send smartphone alerts add another tier of cost but provide remote notification capability that can be valuable in vacation homes or for families with members who sleep through alarms.

Done! can advise on the right detector type for each location in your home and your household’s specific needs before you commit to any purchase.

Colorado Code Requirements

Colorado requires smoke detectors in every sleeping room, outside each sleeping area, and on every level of the home including basements. Carbon monoxide detectors are required on each level and within 15 feet of any sleeping area in homes with gas appliances or attached garages. If your home was built before these requirements were adopted, you may have fewer detectors than current code requires — and if you’re doing any permitted renovation work, a code compliance inspection will flag detector coverage.

Smoke detectors must be replaced every 10 years. Many Denver homeowners who moved into existing homes have no idea when the installed detectors were manufactured. The manufacture date is printed on the back of each unit; if it’s missing or more than 10 years old, replacement is warranted regardless of whether the test button still works.

Should You Hire an Electrician or Do It Yourself?

Replacing an existing hardwired detector with a compatible new unit — same voltage, same manufacturer where interconnection is required — is within most homeowners’ DIY comfort zone. The wire harness typically unplugs from the old unit and connects directly to the new one. Battery-only detectors are always DIY.

Where a licensed electrician adds clear value: adding new detector locations, ensuring the interconnect wiring runs correctly across multiple circuits, installing combination smoke/CO units where new wiring is needed, or troubleshooting why a hardwired detector keeps false-alarming or won’t interconnect with the others. Done!’s electrical team handles all of this and ensures the final installation meets current Colorado code.

Peace of Mind Is the Real ROI

Smoke detectors are among the highest-value safety investments in a home on a cost-per-protected-life basis. A few hours of professional installation ensures every room has working, code-compliant, properly interconnected protection — and that the units will reliably alert everyone in the home simultaneously if smoke is detected anywhere. In a larger home where you can’t hear a detector from the far end of the house, interconnection isn’t a nice-to-have; it’s the point of the system.

Learn more about home safety installations on our smart home and safety page and electrical installations page. Contact Done! to schedule a smoke detector inspection or installation for your Denver-area home.