Checking the smoke alarm has become a rite of fall. (Turn back the clock; check the alarm batteries.) Just as important as a smoke alarm is a carbon monoxide detector. The cold-weather season is when most carbon monoxide poisonings occur, so it's time to take a few preventative steps.

Invest in alarms that detect both smoke and carbon monoxide, such as the new Kidde Nighthawk Smoke and Carbon Monoxide Alarm (runs on batteries, $30, No. 421846, Home Depot, www.homedepot.com).

Install alarms on every floor of your home and outside the bedrooms. Don't place them in a breezy area (like near a ceiling fan) or a spot with no air circulation (like a corner).

Have your heating system checked for carbon monoxide leaks by a heating specialist. To find one, contact North American Technician Excellence (www.natex.org), or look in the Yellow Pages under "Heating Contractors."