Carbon Monoxide and Your Chimney: Furnace and Water Heater Flues in Topeka Homes

When people think about a chimney, they think about a fireplace. But a chimney is also an exhaust pipe, and in many houses it carries the exhaust from a furnace or water heater even if nobody has lit a fire in years. This guide is about that second job: how a blocked or damaged flue can become a carbon monoxide problem, and what a Topeka homeowner can do about it.

This is general safety information, not a diagnosis. Anything that involves a gas appliance, a flue or a suspected leak should be looked at by a qualified person.

What carbon monoxide is

Carbon monoxide, often called CO, is a gas produced any time fuel burns. The Centers for Disease Control and Prevention lists furnaces, fireplaces, stoves, gas ranges, generators and grills among the sources. You cannot see or smell it. The symptoms the CDC lists are a headache, dizziness, weakness, upset stomach, vomiting, chest pain and confusion, and it notes that people often describe them as flu like. Heavy exposure can cause a person to pass out, and sleeping people can be harmed before they notice anything.

How a chimney comes into it

The CDC names blocked chimneys as one way carbon monoxide can build up in a home or cabin, and it advises having your chimney checked or cleaned every year. A chimney can be blocked by:

• Soot or creosote from past wood burning
• Nests, leaves or other debris, especially when a cap is missing
• A piece of the liner or masonry that has come loose
• Something placed in the flue or damper by mistake

The Chimney Safety Institute of America also lists gas heated homes among those that should have annual chimney inspections. For the safety details in this guide we rely on the CDC and the Consumer Product Safety Commission.

Why this matters in a city with older housing

One third party housing summary estimates that about 16 percent of homes in Topeka were built in 1939 or earlier and about 37.5 percent between 1940 and 1969. These are estimates from a real estate data site, not an official count. Older houses are more likely to have a masonry chimney, and some of those chimneys serve a furnace or water heater. That is a general observation, not a statement about your house. If you do not know what your chimney is attached to, a provider can tell you in a few minutes.

If you have replaced a furnace or water heater and are not sure anyone checked how it vents, ask the person who installed it and a chimney provider. We did not find a source that spells out venting rules, so this guide does not state any.

What to do now

1. Install alarms. The CDC advises battery operated or battery backup carbon monoxide detectors near every sleeping area. The Consumer Product Safety Commission advises alarms on every level of the home and outside sleeping areas, and says interconnected alarms are best, so that when one sounds they all do. Check the batteries regularly, for example when the clocks change in spring and fall, and replace alarms according to the maker's instructions or about every five years, as the CDC says.
2. Have the chimney looked at yearly. Several sources, including the CDC and cost guides citing National Fire Protection Association Standard 211, call for an annual check. A visual Level 1 inspection with cleaning is listed at roughly $85 to $950 depending on the chimney, with gas appliances at the low end. Quotes vary, and a provider who sees the job gives the real number.
3. Service fuel burning appliances. The CDC advises having heating systems and other fuel burning appliances serviced every year. That is a job for a heating professional, separate from a chimney sweep.
4. Never use a generator or charcoal grill indoors. The CPSC warns that one portable generator can produce as much carbon monoxide as hundreds of cars, and that generators should not be used inside homes or garages even with doors and windows open.
5. Take symptoms seriously. Flu like symptoms that come and go with time at home, or that affect several people at once, are a reason to get outside and get help. The CDC symptom list above is the place to start.

If an alarm sounds

Move everyone, including pets, outside into fresh air. Call 911 or the gas utility from outside. Do not go back in to find the source, and do not use the appliance again until a qualified person has checked it. When in doubt, treat an alarm as real.

Caution about DIY

Looking up a chimney, climbing a roof or poking around a gas flue are not safe projects for most people. A flue can hide a break in the liner. Gas appliances have their own safety systems that should be handled by qualified people. If you are not sure, ask a provider.

What a provider can check

A chimney provider can generally look for blockages, deposits, cracks and gaps, check the cap and damper, and tell you whether a camera inspection makes sense. Ask what the inspection covers, whether a camera is used, and whether the findings will be written down. If a problem touches a furnace or water heater itself, they may refer you to a heating professional.

Request a quote

If you have not had your chimney looked at in a while, or you are not sure what yours vents, request a quote through this site. An independent provider near Topeka can inspect the flue and tell you what it needs. It is free and there is no obligation to hire anyone.