You have been noticing a faint smell of poop every time you turn on your furnace. The stench is getting stronger and more unbearable by the day, to the point where you can’t even enjoy staying in your own home anymore.
Why does my furnace smell like poop? Is something wrong with my furnace? Am I going to have to replace it entirely? There are many possible explanations for why your furnace might be emitting a foul odor.
In most cases, the problem can be fixed with simple cleaning or repair. This guide will help you identify the source of the smell and provide tips on how to fix it.
What causes a furnace to smell like poop?
The cause of a furnace smelling like poop is usually a faulty trap in one of the drains, a plugged vent pipe, or an installation with faulty or missing vent piping. These conditions allow sewer gas to escape through one or more of the drains and be sucked in by the gas heater when it runs, due to the lack of air in the tightly sealed house. This is more likely to happen in the winter months when the house is closed off and the heater is running more frequently.
Reasons why your furnace smells like poop
1. Feces and urine in the ducts
A common cause of the smell of feces and urine in furnace ducts is a faulty trap in a drain, a plugged vent pipe, or a faulty or missing vent piping. When the gas heater runs, it sucks air out of the house, creating a pressure differential that pulls the sewer gas into your living space. In the summer, when windows are open and the house is well-ventilated, the pressure differential may not be great enough to draw the gas in, so it is more noticeable in the winter.
To identify and fix this problem, homeowners should contact a professional plumber or HVAC technician to inspect the furnace and drains and check for any blockages. If the problem is a septic system, it could be full and need to be emptied.
2. Mold growth
Mold growth in a furnace is caused by moisture buildup from leaky fixtures or broken pipes, poor ventilation, and/or humid or moisture-prone environments such as basements or bathrooms. Excess moisture from the HVAC system can also cause mold and fungus to form in the pipes.
The foul smell associated with mold growth in a furnace is caused by the combination of darkness, oxygen, warmth, and moisture that encourages the growth of fungi and bacteria. A pest infestation can also contribute to this smell, as their urine and feces can accumulate in air ducts.
Regular maintenance and cleaning of evaporator coils and drain pans can prevent the formation of mold and mildew and the unpleasant smell associated with it.
3. Poor ventilation
Poor ventilation of a furnace may be caused by a number of factors, most notably an inadequate fresh air circulation system and the presence of pests or dead animals. Without proper ventilation, moisture can become trapped in the system, creating an ideal environment for mold and bacteria to grow. The resulting musty, sour, or otherwise funky odor can be mistaken for a smell like poop.
To address this issue, homeowners should first check for any air intakes located near smelly objects and make sure the smell is not localized to one room or area. If the odor persists, a technician should be called to inspect the vents and furnace.
The technician can diagnose the issue and, if necessary, repair any leaky pipes or damaged roof, install an exhaust fan or otherwise improve ventilation, and potentially add a dehumidifier attachment to reduce moisture content in the air. If pests are present, the technician can also address this issue.
4. Clogged vents
The common symptoms of a clogged vent in a furnace include an unpleasant, musty smell similar to dirty socks or smelly feet radiating from the furnace; excessive dust, dirt, and debris in the air; air filters become dirty more quickly than usual; the furnace shutting off unexpectedly; and the presence of moisture in the vents or furnace unit.
Clogged vents can also cause the furnace to run inefficiently, leading to higher energy bills. Furthermore, it can lead to the buildup of mold and mildew inside the system, which can cause health problems. To prevent a clogged vent, it is important to regularly inspect and clean the vents and filters and to fix any plumbing or roof leaks that might be adding moisture to the system.
5. Aging HVAC system
The aging HVAC system refers to an older heating, ventilation, and air conditioning system that is not efficiently functioning and may be emitting strange odors. In particular, the HVAC system may be emitting a smell that resembles poop, or a sewage-like odor.
This is a result of a combination of factors, such as water leaks, improper drainage, lack of maintenance, and gathering of dirt and debris in the evaporator coils, ductwork, and drain pan. Additionally, poor ventilation can also contribute to the smell.
Covering up the smell with sprays, aromatic candles, and so on will only worsen the air quality. To avoid these strange smells, homeowners should make sure that their HVAC systems are properly maintained and inspected regularly.
This includes changing the HVAC filters, checking for water leaks and drainage, and cleaning the evaporator coils and air ducts. It is also important to ensure that air is properly circulated and ventilated in the home to prevent odors from occurring.
6. Sewer gas
Sewer gas is a combination of gases that are produced and emitted from the sewer system. It is made up of hydrogen sulfide, methane, carbon dioxide, ammonia, and sulfur dioxide. The gases are odorless, but when combined with the bacteria and other particles found in the sewer, they can produce a foul odor. This odor can be especially noticeable when the gases escape into the living space of your home.
When sewer gas enters your home from a dry plumbing trap (P-trap) or a clogged or broken ventilation pipe, it can cause your furnace to smell like poop. This is due to the methane and sulfur dioxide present in the gas reacting with the electric currents in the furnace and producing a bad smell.
It can also cause the air circulating through your home to have a stale odor. To prevent this from happening, make sure to check that running water from all sinks fills the P-trap and creates a seal against sewer odors, approximately once a month. If the problem persists, you should contact a professional plumber or HVAC technician.
7. Human waste in the furnace room
The cause of the bad sewage smell in the living room in the winter could be due to a faulty trap in one of the drains, a plugged vent pipe, or an installation with faulty or missing vent piping. All of these conditions can cause sewer gas to come out of one or more of the drains, and the heat from the furnace can create a pressure differential that sucks the gas into the living room.
This is especially true when the house is tightly sealed in the winter and the gas heater runs, as it pulls air out of the house and pulls the sewer gas in. In other seasons, when the house is not so tightly sealed and there is more ventilation, the pressure differential may not be great enough to pull the gas into the living space.
8. Garbage disposals
Garbage disposals and furnaces both involve the movement of air and water. Both are connected to a plumbing system, and both involve the use of P-traps that are designed to create a seal against sewer odors. However, the primary purpose of garbage disposal is to grind up food waste, while a furnace is used to heat a home or business. Both a garbage disposal and a furnace require regular maintenance and cleaning in order to work properly.
The garbage disposal needs to be inspected and cleaned regularly, while the furnace needs to have its filters changed and the ducts cleaned on a regular basis. Additionally, if either a garbage disposal or a furnace has a problem, it is important to contact a professional immediately in order to avoid any safety hazards.
9. Cigarette smoke
Smoking indoors can cause the smell of cigarette smoke to accumulate in the filter and evaporation coil of a furnace. When the air conditioner is turned on, the unpleasant odor of cigarette smoke can be noticed. To prevent this, it is best to replace the filter, adjust and clean it, and smoke only outside.
Burning tobacco emits a variety of chemicals, some of which can linger in the air for long periods of time and become embedded in the fabric, furniture, and other porous surfaces. This can lead to a buildup of smoke odor in the air, even if the source of the smoke is removed.
To avoid the smell of cigarette smoke from entering the furnace, it is important to keep the area well-ventilated in order to reduce the amount of smoke that accumulates and to properly clean and replace the filter regularly.
10. Infestations and pest control
Infestations are when unwanted pests such as mice, rats, and other wild animals enter and take up residence in your home. Pest control is the process of preventing, eliminating or reducing infestations of pests. These infestations can cause a number of issues, including odors and smells associated with your heating system.
The odors caused by these pests can be difficult to ignore and quickly become unbearable. Not only do these odors make your home unpleasant, but they can also be signs of hazardous conditions. Rodents, for example, can transmit worms and diseases to humans or pets through their infected feces. To keep everyone safe, it’s important to contact a professional pest control service to remove the infestation.
Excess moisture in the HVAC system can also lead to mold and fungus in the pipes. This can create a musty and unpleasant odor. To prevent this from happening, it’s important to fix any water leaks and invest in a home air dryer. This will help to extract moisture and condensation from the air, thus reducing the chances of mold growth.
How to fix the problem of a smelly furnace
- Check for other sources of odors. Look for air intakes that may be near garbage cans, compost bins, or other sources of smells. If the smell is localized to one area, investigate that area more closely.
- Check for mold and bacteria growth. Moisture, darkness, oxygen, and warmth are the four ingredients for mold and bacteria growth. If you detect any of these conditions in your ventilation system, you may have a mold problem.
- Call a technician. If you’ve ruled out all other sources for the odor, it’s time to call a technician to inspect your vents and furnace. They will be able to assess the situation and advise you on the best solution.
- Fix any moisture problems. If the source of excess moisture is a leaky pipe or damaged roof, the repair should be straightforward. If the air in your home is too damp, you may need to install a dehumidifier attachment to reduce moisture content in the air, preventing mold growth and improving your home’s comfort.
- Check for pest infestation. Rodents and other small pests can get into your ventilation system and die, causing unpleasant odors and potentially dangerous microbes to spread through your home. If the smell is consistent with a pest infestation, you should call a technician to inspect your system for any pests and take the necessary steps to get rid of them.
- Check for electrical issues or frayed wires. If the odor from your furnace is acrid or burning plastic, it could be due to electrical issues or frayed wires. If this is the case, you should turn your furnace off immediately and call a furnace repair technician to assess the situation and fix the problem.
FAQ
Could a gas leak be causing the poop smell in my furnace?
It is possible that a gas leak could be causing the poop smell in my furnace. Natural gas leaks can occur due to a cracked or otherwise damaged heat exchanger or an issue with the gas line itself. In either case, these issues can lead to sulfur or rotten egg odor emanating from the furnace or vents. A gas leak can also make your room smell like poop.
If you smell this smell coming from your furnace or vents, you should immediately shut off the unit and leave your home.
Call your gas company to have them shut off the gas safely so that a technician can come and diagnose the issue. Trying to diagnose the leak yourself is not recommended, as trained technicians have the equipment and knowledge to properly fix the issue.
Could mold be causing the poop smell in my furnace?
Mold growth in a furnace can be a possible cause of the poop smell coming from the vents or furnace unit. The three components necessary for mold growth are moisture, darkness, oxygen, and warmth, and a ventilation system typically provides all of these. If moisture has managed to make its way into the system, mold can quickly form.
Before panicking, however, be sure to check for more mundane sources of the smell, like air intakes near garbage cans or compost bins. If there is no obvious source, a technician should be called to inspect the vents and furnace.
Fixing a mold problem requires diagnosing and fixing the moisture issue, be it a leaky pipe or high humidity levels in the air. A pest infestation can also be the cause of the smell, so an inspection can help determine if this is the case. If so, they will need to be removed, and the ventilation system needs to be cleaned.
Could sewer gas be causing the poop smell in my furnace?
It is possible that the foul smell in my living room during the winter is coming from sewer gas. Dry plumbing traps, or P-traps, are designed to create a seal against sewer odors. If there is not enough running water from all sinks, this seal will not be created, leading to sewage gas.
Additionally, a clogged sewer pipe or a broken ventilation pipe can also cause the issue. As the issue is only present during the winter, when the heat is turned on, this could be the source of the smell. It is important to take action immediately, as sewage gases can be dangerous. I recommend contacting a professional plumber or HVAC technician to investigate the issue.
Why does my heat smell like sewage?
The cause of the bad sewage smell in the poster’s living room is likely due to a faulty trap in one of the drains, a plugged vent pipe, or a faulty installation with missing or incorrect vent piping. The reason this happens more in the winter is that the house is shut tight and the gas heater runs, creating a pressure differential that pulls the sewer gas in. In warmer months, more ventilation is available, which prevents the pressure differential from drawing the gas into the living space.
To solve this issue, the poster should have their landlord look into these possibilities and inspect any drains, vent pipes, and installations for possible faults.
Why is there a poop smell coming from vents?
This is a common issue caused by a variety of factors, such as a backed-up or vapor-locked condensate drain, a lack of water in the condensate trap, or even a dead animal in the walls. The smell usually gets worse when the air conditioner is running, particularly in the winter when the heat is on.
In some cases, the smell can be traced to the radiators which may have accumulated debris that releases an unpleasant odor when heated. To address the issue, it’s important to first identify the source of the smell and then take steps to correct the problem.
For example, if the issue is a backed-up line, you can pour water down the drain pan to fill it. Alternatively, if the smell is due to a lack of water in the trap, adding water can resolve the issue. Finally, if there is a dead animal in the walls, it’s best to call in a professional to help remove it.
Why does my heat smell like fart?
The cause of foul-smelling heat in your house can be due to several things. First, it may be a natural gas issue coming from your furnace or vents. The smell could be sulfur or a rotten egg odor, and in this case you should immediately shut off the unit and leave your home, ensuring you turn off the gas if possible.
Additionally, a cracked or damaged heat exchanger could be causing a natural gas leak. Secondly, you may be smelling sewage or sewer gas, which could be coming from a faulty trap in one of your drains, a plugged vent pipe, or an installation with faulty or missing vent piping.
This is especially likely if you notice the smell more in winter, as the gas heater can suck air from the house and pull in the sewer gas. In either case, it is important to call a technician to diagnose and fix the issue safely.
