Have You Started to Replace Detectors in Your Home? Nothing lasts forever, and your smoke and carbon monoxide detectors are no exception. To be sure, these devices last a very long time, and with proper care and maintenance, you should get your money’s worth. But when the time comes, be prepared to replace detectors.

When to Replace Detectors?

Smoke detectors have a lifespan of about 10 years, although manufacturers’ expiration date may be less than that. Carbon monoxide detectors last from five to seven years. If your current monitors have no expiration dates on on the back, you should replace them, as they are old. Expiration dates are a feature of newer models.

If you’ve only had one of each type of monitor in your home, plan to replace them with several, so that you can put them in these locations.

Carbon monoxide detectors:

  • on every floor
  • near all sleeping areas
  • not where airflow might be blocked

Smoke detectors:

  • inside and outside each bedroom
  • on each level of the home, including the basement
  • living room
  • near the stairway to an upper level
  • high on the wall or ceiling

Smoke rises so that is why you want the detectors higher, but away from stoves so you don’t get false alarms.

Carbon monoxide, a colorless, odorless gas that is a byproduct of the combustion process from fuel-powered appliances, can best be read by monitors when they are about 5 feet from the ground, but no lower than knee level. If you have children, you may want to raise the monitor to where it is out of reach.

Look into getting a CO monitor that provides a digital readout and that has an electro-chemical sensor for greater sensitivity to this deadly gas.

Also, dual monitors are available the detect smoke and CO.


Smoke or CO monitors won’t do much good if they aren’t working. Test them every so often. Replace batteries or check the wiring for wired-in models. The wiring connections should be tight, and the wire should not be frayed.

The experts at Mowery Heating, Cooling and Plumbing can answer your questions about when and how to replace detectors.

Our goal is to help educate our customers in Brownsburg, Indiana and surrounding areas about energy and home comfort issues (specific to HVAC systems).