UPDATED 2021

The Carbon Monoxide Test Guide

The Carbon Monoxide Test Summary
What: Carbon monoxide detectors alert people to toxic levels of the odorless, colorless and tasteless poison gas.
Who: Homeowners should purchase and install carbon monoxide detectors from manufacturers meeting Underwriters Laboratories standards.
Where: Carbon monoxide detectors should be placed near all sleeping areas and in rooms with fuel-burning appliances. The test should be installed at least six feet away from those appliances and from areas of natural air flow. They should be kept away from high
When: Carbon monoxide detectors should be in use at all times, and batteries should be changed at least annually.
How: The tests use sensors to detect the presence of carbon monoxide and sound an alarm. Some detectors provide a digital measure of the gas, which becomes toxic at levels of 50 ppm, or parts per million.
Type: Detectors types include biomimetic, metal oxide semi-conductor and electrochemical. Some varieties include voice alarms and smoke detector combinations. There are portable travel models and ones for recreational vehicles.
Why: Carbon monoxide poisoning kills about 400 Americans each year, some of whom die in their sleep without waking to experience symptoms. Another 20,000 people need medical care after carbon monoxide exposure.
Time: Alarms sound within one to 45 minutes of detecting carbon monoxide, depending on the level of exposure.
Language: Many carbon monoxide detector manuals are written in English and Spanish.
Preparation: Carbon monoxide detectors can be installed any time, and fresh batteries should be available.
Cost: Detectors cost from $20 to $75.

Carbon monoxide, often called a “silent killer,” is a colorless, odorless and tasteless poisonous gas produced in the burning of common fuels. Unintentional exposure to lethal levels of carbon monoxide kills about 400 Americans each year, according to the Centers for Disease Control and Prevention. In addition, the poison sends about 20,000 people to the emergency room annually and more than 4,000 of them are hospitalized.

Why Test for Carbon Monoxide?

Carbon monoxide poisoning may kill people in their sleep, with victims never waking to experience any symptoms. Even in waking hours, victims may mistake the poisoning symptoms for the flu or even intoxication. Those exposure symptoms can occur as the carbon monoxide limits red blood cells from absorbing oxygen, causing headache, fatigue, nausea, dizziness, mental confusion and shortness of breath. Heart patients may suffer chest pains.

Carbon monoxide detectors, which are legally required in some cities, use sensors and sound an alarm so that potential victims can get to safety. The devices however, are no substitute for the proper use and upkeep of furnaces, ranges, wood stoves, water heaters, room heaters and fireplaces. Annual inspections of furnaces, water heaters and fireplaces are a good idea, as is fixing any damage immediately. In addition, homeowners should never operate items like generators, lawn mowers and power washers indoors – even in a garage with the door open. Carbon monoxide levels can build up and remain for hours even after the motors are turned off.

Choosing a Detector

Carbon monoxide detectors can be found in most hardware departments and in many supermarkets. Costs run from $20 to $75 and warranties usually cover the tests for five years of use.

There are three basic test types – biomimetic, metal oxide semi-conductor and electrochemical. Biomimetic detectors are battery operated and use synthetic hemoglobin-coated discs which darken and sound an alarm when sensing carbon monoxide.

Metal oxide semi-conductor detectors contain heated tin oxide wires on an insulating ceramic base. The wires act as sensors and react with carbon monoxide. These detectors often need household electricity but also utilize batteries.

Electrochemical detectors contain a fuel cell that produces a current in relation to the amount of carbon monoxide present. They measure the poison’s concentration and usually provide a digital readout of current and past toxin levels.

Underwriters Laboratories, an independent product safety certification organization, recommends choosing a detector with the UL mark and phrase “single station carbon monoxide alarm.”

Installing a carbon monoxide detector and determining placement are simple jobs, but be sure to follow the specific manufacturers’ instructions completely. Place detectors near all sleeping areas. Do not place a detector within six feet of natural air flow or cooking appliances. The tests should also be kept away from unheated basements, high humidity, vents, chimney flues, household cleaners and hairspray. Detectors that plug in should not be in an outlet controlled by a wall switch. The batteries in battery-operated detectors should be changed at least once a year.

Carbon monoxide detector price ranges reflect available options. Some tests come with low battery indicators and some are combined with smoke detectors. Higher-end carbon monoxide detectors include a choice of voice warnings and may be linkable to other detectors in the home. Increasingly detectors are sold with easier to reach battery doors than previously made models.

Specialty carbon monoxide detectors are made for installation in recreational vehicles and trailers powered by generators. Owners of gas-powered boats should also install detectors. Travelers can buy portable detectors for use in hotel rooms.

When carbon monoxide alarms sound, people should get outside immediately and then call the fire department. Those who stay inside could lose consciousness and be unable to seek help.

Are you interested in finding a carbon monoxide detector? Take a look at our Carbon Monoxide Test Directory. Also, be sure to read our interview with carbon monoxide test expert David Heldenbrand.