For current safety information, review the U.S. Consumer Product Safety Commission Carbon Monoxide Information Center and the U.S. Fire Administration. Colorado homeowners, landlords, tenants, and property managers should also confirm current state and local requirements with the appropriate authority before relying on this general guide.
Carbon monoxide, often called CO, is a poisonous gas that can build up when fuel-burning appliances or engines do not operate or vent properly. It is colorless and odorless, so people cannot reliably detect it without an alarm. A home can appear clean, quiet, and safe while CO is accumulating indoors.
That is why CO alarms are not optional safety accessories. They are an important early-warning system for a hazard that can affect sleeping occupants first. Every household should understand where alarms belong, how to maintain them, and what to do when one sounds.
Why is carbon monoxide dangerous?
Carbon monoxide interferes with the body’s ability to use oxygen. Exposure may cause headache, dizziness, weakness, nausea, vomiting, chest pain, confusion, or unusual tiredness. Symptoms can resemble the flu, food poisoning, exhaustion, or another illness. People who are asleep may not recognize symptoms before exposure becomes serious.
The risk is especially concerning for infants, older adults, pregnant people, and anyone with certain medical conditions. Pets can also be affected. Because symptoms are not always obvious and CO cannot be seen or smelled, an alarm provides a critical warning that human senses cannot provide.
Where can carbon monoxide come from?
CO may be produced by fuel-burning equipment, including furnaces, boilers, water heaters, fireplaces, wood stoves, gas ranges, and other appliances. Portable generators, vehicles, grills, and other engines can also create dangerous CO levels when used in or too close to an enclosed or partially enclosed space.
Blocked, damaged, disconnected, or poorly maintained vents can allow combustion gases to enter a home. Snow, ice, leaves, nests, construction materials, or other debris may obstruct an outdoor vent. A cracked heat exchanger or a malfunctioning appliance can also create a hazard.
Do not assume that a newer appliance eliminates the risk. Proper installation, regular inspection, safe operation, and working alarms all matter.
How many CO alarms should a home have?
General federal safety guidance recommends placing CO alarms on every level of a home and outside sleeping areas. Follow the installation instructions supplied with each alarm, because placement details can vary by product. A home with multiple bedrooms may need more than one alarm to provide effective warning near sleeping occupants.
Consider the layout of the home, the location of fuel-burning equipment, attached garages, and areas where people sleep. An alarm should be close enough to be heard from bedrooms, including when doors are closed. Large homes, split-level homes, and homes with separate sleeping areas may require additional units.
Colorado requirements may differ based on the property type, construction date, fuel-burning equipment, occupancy, and local jurisdiction. Confirm the current state and local rules rather than relying on an older checklist or advice from a previous owner.
Where should a CO alarm be installed?
Install alarms according to the manufacturer’s instructions, generally on each level and outside sleeping areas. Keep the alarm where its sound can wake occupants. Avoid placing it in a location where normal household activity could damage the unit or make it difficult to hear.
Do not place an alarm directly beside a cooking appliance, heating appliance, fireplace, window, door, ceiling fan, or ventilation opening unless the instructions specifically allow that location. Steam, humidity, dust, cleaning products, and air movement may affect some alarms or cause nuisance alerts.
Do not cover, paint, disconnect, or remove an alarm because it is inconvenient. If nuisance alarms occur, investigate the cause and consult the manufacturer or a qualified professional. Moving the alarm without understanding the problem may reduce protection.
Should a home have both smoke alarms and CO alarms?
Yes. Smoke alarms and CO alarms detect different hazards. A smoke alarm is designed to warn about smoke and fire conditions. A CO alarm is designed to warn about carbon monoxide. One device should not be treated as a replacement for the other unless it is a properly listed combination unit that provides both functions.
Check the labels and instructions on every alarm. Make sure household members know which alarm is sounding and how to respond. Combination alarms can be useful, but they still need to be installed and maintained according to the product instructions.
How often should CO alarms be tested?
Test CO alarms regularly using the test button and follow the manufacturer’s directions. The U.S. Fire Administration encourages routine alarm testing as part of household fire and life-safety practices. A test confirms that the alarm can produce its warning sound, but it does not prove that the sensor will detect every hazardous condition.
Do not use a vehicle exhaust pipe, appliance emissions, or another improvised method to test an alarm. Such methods can expose people to dangerous gas or damage the device. Use only the testing method approved by the manufacturer.
Include alarm testing in a recurring household routine. Mark a calendar, use a phone reminder, or coordinate testing with another regular home-maintenance task.
When should CO alarm batteries be replaced?
Replace batteries according to the manufacturer’s instructions and whenever the unit produces a low-battery warning. A low-battery chirp is not the same as a CO alarm, but it should never be ignored. A device with a depleted battery may fail when it is needed.
If the alarm has a sealed battery, replace the entire unit when the manufacturer’s service life ends or when the unit indicates that replacement is required. Do not attempt to open or modify a sealed alarm.
Keep replacement batteries away from children and dispose of used batteries according to local guidance. After changing a battery, press the test button and confirm that the alarm is operating normally.
How long do CO alarms last?
CO sensors do not last forever. The manufacturer’s instructions should state the expected service life and replacement process. Replace an alarm when it reaches the end of that period, even if it appears clean and still responds to the test button.
Replace a unit sooner if it is damaged, contaminated, repeatedly malfunctions, or has been exposed to conditions outside its operating specifications. Record the installation date on the alarm or in a home-maintenance file so the replacement timeline is easier to track.
When buying a new alarm, select a product that is appropriate for the location and use it only as directed. Confirm that the alarm is approved or listed under the applicable product-safety requirements stated by the manufacturer.
What should you do if a CO alarm sounds?
Take the alarm seriously. Move everyone, including pets, outside to fresh air immediately. Do not stay inside to search for the source, silence the alarm, gather belongings, or open windows first. Once outside and away from the suspected exposure, call emergency services or the appropriate emergency response number.
Do not re-enter until responders or another qualified authority says it is safe. If anyone has symptoms, seek emergency medical assistance. Tell responders that a CO alarm sounded and describe any symptoms, appliance use, generator use, vehicle use, or other possible source.
If the alarm stops sounding after people leave, that does not prove the home is safe. CO levels may change as appliances cycle, ventilation changes, or doors and windows open. The source still needs to be evaluated.
What if someone has CO poisoning symptoms?
Leave the area and seek immediate medical help when symptoms could be related to CO. Do not try to diagnose the cause at home. Headache, dizziness, nausea, weakness, confusion, chest pain, and shortness of breath can have many causes, but possible CO exposure requires urgent attention.
Tell medical personnel about the alarm, the suspected exposure, and when symptoms began. If more than one person develops similar symptoms at the same time, treat that pattern as especially serious. Never return indoors simply because someone feels better outside.
Are generators safe in a garage or near a home?
No. A portable generator can produce deadly CO in a short period. Never operate a generator inside a home, basement, garage, crawl space, shed, or other enclosed or partially enclosed area. Opening a garage door or window does not make indoor generator use safe.
Place generators outdoors and far from doors, windows, and vents, following the manufacturer’s instructions and current safety guidance. Exhaust can enter through openings that are not obvious from the generator’s location. Keep people and pets away from hot surfaces and fuel.
Portable fuel-burning equipment should never be treated as an indoor heating solution unless it is specifically designed and approved for that use.
Can a vehicle create carbon monoxide in a garage?
Yes. A vehicle can produce CO even when the garage door is open. Never run a vehicle in an attached garage, whether the garage door is open or closed. Do not warm up a vehicle in a garage before driving away.
After heavy snow, check that vehicle tailpipes are clear before starting a vehicle outdoors. Snow can block exhaust and allow CO to enter the passenger compartment. Be cautious with remote-start systems and never leave a running vehicle in an attached garage.
Who should inspect fuel-burning appliances and vents?
Use qualified, appropriately licensed professionals as required by current Colorado and local rules. Arrange inspections and service according to the equipment manufacturer’s instructions and the needs of the property. A professional can evaluate combustion, venting, connections, and other conditions that a homeowner may not recognize.
Do not remove a furnace panel, alter a vent, repair a gas connection, or bypass a safety control unless you are qualified and authorized to perform that work. Keep vents, chimneys, flues, and outdoor appliance openings clear of debris and snow, but do not make changes that conflict with installation requirements.
What should landlords and tenants know about CO alarms?
Landlords, property managers, and tenants should identify who is responsible for installation, testing, battery replacement, reporting problems, and replacing expired units. Written move-in instructions can help residents understand alarm locations and emergency procedures.
Tenants should promptly report missing, damaged, chirping, expired, or malfunctioning alarms. Do not disconnect an alarm because of nuisance alerts. Ask the property owner or manager to investigate the cause and confirm that the alarm is correctly installed.
Because requirements can change and may depend on the property, confirm current Colorado law and local housing or fire-safety guidance before creating a rental policy or lease provision.
What should homeowners do before winter?
Before using a furnace, fireplace, wood stove, or other seasonal equipment, verify that CO alarms are installed in the recommended locations, have working batteries, and are within their service life. Check that vents and exhaust outlets are not blocked by snow, ice, leaves, or stored materials.
Schedule needed maintenance before cold weather increases demand on heating systems. Review generator placement and vehicle safety with everyone in the household. Make sure visitors, babysitters, and older children know that a sounding CO alarm means leaving immediately.
How can a household create a CO safety plan?
Start by identifying every fuel-burning appliance, attached garage, fireplace, generator, and sleeping area. Then map the locations of CO alarms and write down the date each unit was installed. Add recurring reminders for testing, battery checks, and replacement.
Choose an outdoor meeting location far enough from the home to avoid possible exposure. Teach everyone to leave when an alarm sounds and to call for help from outside. Do not assign one person to investigate while others wait indoors.
Finally, confirm current guidance before making changes to a home or rental property. The CPSC and U.S. Fire Administration provide important safety information, but state and local requirements may apply separately. Confirm locally with the relevant Colorado authority, building department, fire department, housing agency, or qualified professional.
CO alarms are not optional because carbon monoxide is invisible, odorless, and potentially fatal. Install the right alarms, maintain them, respond immediately, and confirm current Colorado requirements for your specific property.