Why Does My Furnace Smell Like Poop? [SEE HERE!]

Is there an odd smell coming from the gas furnace? You should be able to tell the difference between the feces smell, which is likely coming from the sewer gas, and a dead squirrel, which should stink like rotting meat.

Check your radiators for debris or gross stuff. If there is, clean it off.

Now, let’s get back to the sewage. I can bet that you have a faulty trap in one of your drains, a plugged vent pipe, or a missing vent piping, or an installation with faulty vent piping.

Any of these conditions would force the sewer gas to come out of one or more of your drains. The reason this happens more in the winter is that you shut your house tight, and when the gas heater runs, it sucks the air out of the house, therefore pulling the sewer gas in.

Then when summer comes in, your ventilation increases, and the pressure differentials may not be great enough to pull the gas into your living space. In other news, this is bad news and this stuff is not good safe for you and if enough of it builds up, it will explode. Entire houses have been blown to smithereens in this kind of explosion.

Why Does My Furnace Smell Like Rotten Eggs?

The only way smells like this from the basement could get into your system is if the ductwork is leaky.

This means either one or more connections are loose or even disconnected, in your basement. So, check to see if it is. If the ductwork is relatively tight, without any large disconnections or air gaps, then I would be looking at the bathroom that is closest to the return air grille.

The return-air grille draws air from the surrounding space to circulate it thru the ductwork. If a bathroom is close by, it will draw air from there, as well.

If the shower, sink, or tub is not used often, the water that fills the trap, to prevent sewer gases from coming up thru the drain, can slowly evaporate, allowing air space for sewer gases to escape.

These gases will be pulled towards the return-air grille, sucked thru the duck work, and will dump out at all of the registers.

To fix this, you need to run the shower, tub, or sink faucets for 60 seconds, at least once a month, to keep the traps full.

Another possible cause for the rotten egg smell in your home would be if the wax ring on the bottom of the toilet is not sealing well, and the sewer gasses get pulled past the wax and towards the return grille.

To fix this mess, remove your toilet and replace the wax ring. Once that is done, ensure your traps are full of water first then test it.

HVAC Smells Like Poop Only When Ac Is Turned On

The condensate line trap requires water to work effectively. It was probably full during the summer and dried up during the winter months and it hasn’t produced enough water to seal any sewer gas from leaking in. You can pour water down the drain pan to fill it.

Or You are probably getting a “dirty socks syndrome”. It occurs when a heat pump goes from defrosting back to heat. I recommend trying some XO Deodorizer on the coil. Sometimes once a year does the trick.

Or There might be really pooping in there.  Perhaps, someone is trying to get back at you.

Furnace Smells Like Skunk

Chances are, there is a gas leak in your HVAC. I suspect ‘methyl mercaptan”; a gas that smells a whole lot like skunk’s spray. It might already be in your home.

This is a dangerous gas to be leaking. You and your family are in danger as it could blow the whole house to smithereens.

Another possibility is that what you smell is ‘dirty sock syndrome”. It’s from bacteria building up on the evaporator coil and then drying out in the heat. Trans use to recommend changing the coil and a black fin coil was the fix for it.

Look, get your family out of that house and call an HVAC to come to check. Better to be safe than sorry.

ALSO SEE: Why Does My Poop Smell Like Cow Manure?

Furnace Smells Like Dead Animal

A dead animal smell in your furnace could be a rat, mouse, or some other type of rodent who may have crawled into there and couldn’t get out. So, it died of heat, cold or starvation.

Furnace Smells Like Perfume

People do this when selling a house. Check behind the filter and see if there is a can or bottle of perfume or other scents there. People place one there and fire up the heater so the smell would fill the house.

Chemical Smell from Furnace

A chemical smell from the furnace, when it’s turned on, may mean that your furnace heat exchanger has a crack.

The heat exchanger’s main role is the removal of the heater air and fumes from the furnace’s combustion chamber and carrying out and away from your home.

Carbon Monoxide Sweet Smell

Is there an unexplained sweet smell in the house? A sweet or yeasty smell is dangerous.

You should call a professional out as soon as possible. There is a high chance you’re picking up on carbon monoxide, which is very dangerous. However, there’s also a chance that what you’re smelling is mold in the vents.

New Furnace Smell How Long Last

A new furnace smell will go away after one or two good burnings, but if it takes longer, then it should be gone within a week/. So, raise some windows and fire it up and hold on.

Ozone Smell from Furnace

The ozone smell you have now is from your electronic air cleaner. it is a byproduct of zapping dust/debris.

Sweet Smell from Furnace

Get yourself and your family out now! Call the gas co ASAP and have them come to check for CO carbon monoxide. It has no smell (at least most of the time_ but the fumes from the furnace do and it travels with them.

Lots of people report a sweet smell and headaches when they are experiencing CO poisoning.

You should also get 2 new CO detectors as they fail with old age. 1 in your bedroom and the other in the furnace area.

Safety Comes first and It costs zero dollars to get the gas co or Fire Department down to check for CO. A lot of people have slept and NEVER work up from that stuff or ended up in comas.

After that, you should check for sewer gas smells or other possibilities but getting CO checked when smells and headaches are mentioned is a red flag red alert scenario.

Sickly Sweet Smell in Furnace and House

Cat pee, mold, or dead mouse in ductwork are common causes of sickly sweet smells in furnaces and homes.

If it’s isolated in one room… probably ductwork that needs to be replaced.

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