How can I figure out the source of a vague smoke smell in our house?

January 22, 2022 5:40 PM

We have a smoke smell in our house that shows up maybe once a week, and then disappears. I’m trying to figure out where it’s coming from but I’m completely stumped.

Some facts to help narrow it down:
- We live in a house with oil heat and hot water radiators. No vents anywhere.
- Each time I’ve smelled it I walk around the furnace and electrical panel area, no smoke smell there.
- We have a pellet stove that exhausts into the house chimney, but it’s been off for a number of hours now and I just smelled it maybe 20 minutes ago.
- I swear I smell it in the same part of our basement stairwell every time, but can’t seem to smell it at the bottom or top of the stairs. Just halfway down.
- I also swear I smell it around 7/8pm or so each time, but it’s possible that’s just recent memory.
- On at least one occasion I’ve found a burnt piece of food touching the heating element in our dishwasher, which I thought was the culprit (it’s near the stairs) but i just checked and it doesn’t seem to be burning anything right now.
- we have plenty of smoke detectors, all with fairly new batteries. None have gone off.

How should I continue investigating? And if I can’t find it, who would I call? If there’s a wiring issue, Is there a reliable way to find the source?

Thanks! Any tips would be useful!

posted by summerteeth to Home & Garden (12 answers total)

What kind of smoke does it smell like? If it's woodsmoke, could it be from a neighbour using their fireplace and a bit of air drifting into your house or being pulled in by your ventilation? Very occasionally I smell something similar in our neighbourhood, but more often it's when I'm out for a walk. (Maybe a neighbour likes to have a fire in the evening around once a week.)
posted by heatherlogan at 6:15 PM on January 22, 2022

Here's two approaches firefighters use, if they help any?

...also, some locations of Home Depot & Lowes rent out thermal imagers at semi-reasonable rates, which might help you check wiring and the like.
posted by aramaic at 6:24 PM on January 22, 2022

I would call the fire department the next time you smell it and explain that you have an intermittent faint smoke odor that keeps occurring in the same part of your house and you are smelling it now. Most fire departments have hand-held thermal cameras that can see hot spots in the wall that could be a sign of a smoldering condition from an electrical short somewhere. It is worth a service call to find it before it becomes a Situation. If they don’t find any hot spots anywhere in the house, then better safe than sorry.

I’m recommending this because I had a fire in my wall from this kind of thing where I was smelling very faint wood smoke for at least an hour and could not pin it down. Smoke detector did not go off. In my case, an electrical short occurred in my attic that found its way to metal flashing at the base of my house. The electricity went to ground through a nail which heated up like an oven element that “cooked” a pile of sawdust (carpenter ant frass) that was covering the exposed nail. The sawdust turned into char that eventually ignited into an actual flame. Apparently, the ignition point of wood becomes lower as it turns to char. So, this weird confluence of factors that caused my fire is almost certainly not your exact situation at all—but I’m telling the story so you know why I think it is worth a call to the fire department to make sure you don’t have a hot spot somewhere.
posted by DB Cooper at 6:30 PM on January 22, 2022

My house has a fireplace that we've never used, in almost three years of living here.

It smells faintly but clearly of woodsmoke, and the scent can drift a bit around the room any time the sun warms the chimney, even in the Illinois winter.

I think when you smell smoke, it's the burning wood fire you sometimes have in your house, even if it hasn't burned in a while.
posted by SaltySalticid at 7:33 PM on January 22, 2022

Is it a stale smoke smell or an active fire smoke smell? If it's stale, my guess would be air currents from your chimney, perhaps that are only flowing in certain conditions. That's something I've experienced before if the chimney cleanout wasn't entirely sealed. Creosote and ash that collects in the bottom of the chimney can have a fairly strong smell. Maybe sniff around the chimney as much as possible next time you smell it? Or go ahead and empty everything out of the bottom of the chimney anyways. You shouldn't have much there with a pellet stove, but there may be enough for you to smell.
posted by ssg at 7:58 PM on January 22, 2022

I think the suggestions above are solid - for us we've had smells pulled through the house when the bathroom fan is on - for us this happens on a somewhat regular schedule because of the kid routine, I'd look for other routine/time oriented things - do you run a washer/dryer consistently - is this typically when the basement lights are turned on, etc. We had a cheap light in a kids room years ago that would start to smell bad after it had gotten to temperature but the room only had the light turned on for maybe 30 minutes in the evening so it took months to track down.

I don't know of a reliable way to test for combustion aside from the thermal imager suggestions.
posted by iamabot at 8:50 PM on January 22, 2022

Smoke smells in my house are usually from outside, in the evenings, when neighbours are using their woodburners for heating or cosiness. They come in through the draughty front door, the kitchen extractor hood and sometimes the extractor fans in the bathrooms, and then wander around seemingly at random. (Air currents are mysterious.)

I also have a 300W halogen uplighter that sometimes incinerates something, but presumably you'd have mentioned it if you had anything similar.
posted by ManyLeggedCreature at 1:23 AM on January 23, 2022

Your local fire department would be much happier to come check it out for you with a thermal imager, I bet, than they would be to get called with the house on fire. At least, that's been the case in my and family/friends experiences, in both rural and metro areas.

I'm also super-sensitive / borderline paranoid (having lived through multiple fires) to the smell of smoke in my house, so I tend to attempt to identify it pretty darn quick. If there's not a scent outside that might have drifted in, pretty much every outlet, switch, and plug gets felt, felt around on the wall, and/or visually examined. (Doing it at the moment reduces the chance it will turn into future intrusive, compulsive-checking thoughts.)

That practice has prevented not one, but two wall fires that would have began in outlet boxes, one in a rental home, one in my workplace. Sure, it's gotten me some annoyance from people, but whatever. Possible house fires are just not something I'm willing risk, consciously or subconsciously, even if it crosses the line into anxiety, OCD, and paranoia, lol. I mean... get struck by lightning enough times, you'd stop going out during a darn storm, right?
posted by stormyteal at 2:00 AM on January 23, 2022

I am not generally a paranoid person, but I would definitely call the fire department to check with a thermal imager just on the off chance that it is a wiring short inside a wall. Consequences for them coming out and finding nothing are much more palatable than the consequences of a possible electrical fire.
posted by ananci at 6:02 AM on January 23, 2022

Do you live in an older house which could have been damaged by fire long before you moved in? If there was fire damage which was repaired, the studs inside the walls might still smell smoky and give off an occasional whiff. We had a similar issue and that was the case.
posted by MelissaSimon at 6:39 AM on January 23, 2022

While you should definitely eliminate other possibilities, I'll second MelissaSimon that it could be from previous fire damage. My family home was damaged by fire, the interior was completely gutted and killz primer used on the remaining framing, but still sometimes we get a faint whiff of smoke in some areas.
posted by Preserver at 8:38 AM on January 23, 2022

Are multiple people smelling it at once? Many people recovered/recovering from covid report phantom smoke smells.
posted by EarnestDeer at 9:49 AM on January 23, 2022