Where did the smoke come from?
October 9, 2022 8:24 PM Subscribe
I woke on Thursday morning to smoke detectors alerting, visible smoke, and a burning smell. The fire department came and was unable to find a fire or a source for the smoke, and the smoke cleared. Where did the smoke come from?
The fire department used thermal cameras as well as a VOC detector. I've since had the HVAC inspected as well as an electrical inspection. Visible smoke was only upstairs in the two bedrooms, with more in the guest room. There was some haze downstairs and the air purifier in the downstairs living room had kicked into a higher mode to filter. The smell was somewhat of burnt plastic but not overwhelming.
I've visually inspected all electronics, outlets, switches, light fixtures -- anything powered. There's no lingering smell in the house at all. What could be the source of the smoke that would have not been a fire and cleared itself and left no sign?
The house is a single family home, a cape cod, in a suburban area.
The fire department used thermal cameras as well as a VOC detector. I've since had the HVAC inspected as well as an electrical inspection. Visible smoke was only upstairs in the two bedrooms, with more in the guest room. There was some haze downstairs and the air purifier in the downstairs living room had kicked into a higher mode to filter. The smell was somewhat of burnt plastic but not overwhelming.
I've visually inspected all electronics, outlets, switches, light fixtures -- anything powered. There's no lingering smell in the house at all. What could be the source of the smoke that would have not been a fire and cleared itself and left no sign?
The house is a single family home, a cape cod, in a suburban area.
Do you have an airconditioner that sucks in air from outside the house?
Could your neighbours have been burning rubbish; or over-cooking their barbeque?
posted by chariot pulled by cassowaries at 9:34 PM on October 9, 2022 [2 favorites]
Could your neighbours have been burning rubbish; or over-cooking their barbeque?
posted by chariot pulled by cassowaries at 9:34 PM on October 9, 2022 [2 favorites]
Do you run a dishwasher overnight? Sometimes a fragment of food can get stuck on a drying element and burn during the drying cycle.
I had mysterious burned smells once when I accidentally turned on the stove timer and the stove came on, cooked for a while and then turned off again all while we were out of the house.
If your heat came on recently, some part that's out of the air path could have cooked itself. Capacitors in heat pumps are notorious for this.
posted by jamjam at 9:59 PM on October 9, 2022 [6 favorites]
I had mysterious burned smells once when I accidentally turned on the stove timer and the stove came on, cooked for a while and then turned off again all while we were out of the house.
If your heat came on recently, some part that's out of the air path could have cooked itself. Capacitors in heat pumps are notorious for this.
posted by jamjam at 9:59 PM on October 9, 2022 [6 favorites]
I had a similar incident a few years ago. Mine was a fire in the hot water heater, the hidden damage was contained under the metal casing. I found it by removing a small panel at the front of the heater.
posted by jennstra at 10:55 PM on October 9, 2022 [2 favorites]
posted by jennstra at 10:55 PM on October 9, 2022 [2 favorites]
Sometimes accumulated lint in a lint trap or an aluminum dryer outlet tube can catch fire and burn.
posted by jamjam at 11:07 PM on October 9, 2022 [1 favorite]
posted by jamjam at 11:07 PM on October 9, 2022 [1 favorite]
+1 to dryer. Is your dryer on or near the bedroom level? The reason annual cleaning of exterior dryer vents is recommended is because of the buildup of lint (not in the lint trap) that’s a fire risk. It happened in a house I was living in. Smoke poured out from behind the dryer. Though in my case it was followed a while later by flames.
posted by ImproviseOrDie at 1:30 AM on October 10, 2022 [1 favorite]
posted by ImproviseOrDie at 1:30 AM on October 10, 2022 [1 favorite]
Seconding 'If only I had a penguin...' and 'jamjam' and 'jennstra'. Pretty much everybody. If you've turned on heat for the first time, dust may be on the heating elements, turning on the heat in the winter is a burn off incident. Were I to turn on the bathroom radiant heater when it turns cold, the smoke alarm will probably go off unless I open a window. Turning on the gas wall heater in the winter for the first time does the same. A bit of smoke, but just no more than a burnt dinner on the stove.
Same can happen with junction boxes or electronics.... does everything still work?
Are you sure the alarm wasn't also triggering on carbon monoxide? (the visible smoke makes this unlikely).
I have seen 'smoke detectors' go off from just dust and even just steam from a hot shower. They can be finicky.
There are two types of smoke alarm. One of em aint so good. - YouTube
posted by zengargoyle at 1:56 AM on October 10, 2022
Same can happen with junction boxes or electronics.... does everything still work?
Are you sure the alarm wasn't also triggering on carbon monoxide? (the visible smoke makes this unlikely).
I have seen 'smoke detectors' go off from just dust and even just steam from a hot shower. They can be finicky.
There are two types of smoke alarm. One of em aint so good. - YouTube
posted by zengargoyle at 1:56 AM on October 10, 2022
Heat strips can cause a burning smell, but not usually a haze. Do you have older fluorescent lights? It could be a bad ballast, and if the crew that visited was young/inexperienced or doesn’t run a lot of commercial calls they may be unfamiliar. And yes, if you’re not having your dryer exhaust serviced annually/time period relevant to how many months the home is occupied, please do that. Dryer fires are real, and they can get real bad, real quick.
Story time! We had a similar call in a larger hotel at 3 in the morning; it was a troublesome property for the dept I worked for at the time so I wasn’t expecting much…until I walked inside and there was about 3’ of haze banked down from the drop ceiling and a characteristic odor. Long story short, after we couldn’t find anything in the whole damn hotel and we’d moved about 600 ceiling tiles, I took the TIC to the electrical panels and there had been a smol fire/smoldering from a burnt up circuit breaker. I hit the main and made the maintenance crew leader call an electrician before they restarted anything powered from that panel. Electrician confirmed that was the problem. Circuit breakers can do their job! Sometimes when they do, they burn up. They can also end up eventually smoldering and causing fires albeit not often (source: a class I took at fire prevention school many years ago and the reason I knew to check out the panel at the hotel). Sometimes they need replaced; like everything else in our houses, they wear out too.
I would call a second electrician to come out and check all of the outlets/junction boxes - I’m a little surprised the first one didn’t find anything. I had an electrician visit my house for a burning smell I couldn’t place (it ended up being not electrical in nature, so he didn’t find anything after 2 hours of looking). They can also determine if something somewhere is drawing too much of a load and take a look at the status of your breakers if the first electrician didn’t do so.
posted by sara is disenchanted at 2:28 AM on October 10, 2022 [11 favorites]
Story time! We had a similar call in a larger hotel at 3 in the morning; it was a troublesome property for the dept I worked for at the time so I wasn’t expecting much…until I walked inside and there was about 3’ of haze banked down from the drop ceiling and a characteristic odor. Long story short, after we couldn’t find anything in the whole damn hotel and we’d moved about 600 ceiling tiles, I took the TIC to the electrical panels and there had been a smol fire/smoldering from a burnt up circuit breaker. I hit the main and made the maintenance crew leader call an electrician before they restarted anything powered from that panel. Electrician confirmed that was the problem. Circuit breakers can do their job! Sometimes when they do, they burn up. They can also end up eventually smoldering and causing fires albeit not often (source: a class I took at fire prevention school many years ago and the reason I knew to check out the panel at the hotel). Sometimes they need replaced; like everything else in our houses, they wear out too.
I would call a second electrician to come out and check all of the outlets/junction boxes - I’m a little surprised the first one didn’t find anything. I had an electrician visit my house for a burning smell I couldn’t place (it ended up being not electrical in nature, so he didn’t find anything after 2 hours of looking). They can also determine if something somewhere is drawing too much of a load and take a look at the status of your breakers if the first electrician didn’t do so.
posted by sara is disenchanted at 2:28 AM on October 10, 2022 [11 favorites]
Less smoke, but similar event for us turned out to be the fuse in the back of the refrigerator. There was some char on the outlet, which was the source of the smell and smoke, but the fuse did its job and prevented a larger fire.
posted by Dashy at 5:57 AM on October 10, 2022
posted by Dashy at 5:57 AM on October 10, 2022
Back when I was a volunteer firefighter 45 years ago we had a call for smoke in the house. We trooped all over the house and could find nothing. Finally I asked if they had been cooking anything. Sure enough, a little pot of leftovers had been simmering on the stove and was forgotten. Not what happened to you I’m sure but I mention it to add to the list of possibilities in this situation.
posted by beagle at 7:37 AM on October 10, 2022
posted by beagle at 7:37 AM on October 10, 2022
Response by poster: The electrician looked at all the breakers (two stories away from the bedrooms) and also checked every single light, outlet was working. My husband and I repeated that two days later. The fire department also checked all outlets.
The level with the bedrooms has just the two bedrooms with a small hall and bathroom in between.
The fire department, while there was smoke, used thermal cameras to look for anything in the wall. I'd say they were an experienced crew -- it was three towns of fire departments responding and two of Chiefs spent hours going through my house.
The heat had been on for a least a few weeks.
It was early morning and I was asleep, so not much was on. There was no burning smell or smoke outside when I evacuated. The dryer, hot water heater, etc are two stories away from the bedrooms and there are closer smoke detectors that did not go off (we have them in nearly every room). The only smoke detector that did go off was in the guest bedroom (but the rest went off because they are networked Nest detectors).
posted by miscbuff at 8:37 AM on October 10, 2022
The level with the bedrooms has just the two bedrooms with a small hall and bathroom in between.
The fire department, while there was smoke, used thermal cameras to look for anything in the wall. I'd say they were an experienced crew -- it was three towns of fire departments responding and two of Chiefs spent hours going through my house.
The heat had been on for a least a few weeks.
It was early morning and I was asleep, so not much was on. There was no burning smell or smoke outside when I evacuated. The dryer, hot water heater, etc are two stories away from the bedrooms and there are closer smoke detectors that did not go off (we have them in nearly every room). The only smoke detector that did go off was in the guest bedroom (but the rest went off because they are networked Nest detectors).
posted by miscbuff at 8:37 AM on October 10, 2022
I wonder if this could have been caused by a component inside of an electronic device failing and letting out the "magic smoke" (though it sounds like more smoke than I am used to seeing from that kind of failure). I know you said you visually inspected all electronic devices, but did you actually confirm that every single electronic device is still working correctly? An internal failure might not be obvious from visual inspection.
posted by primethyme at 9:14 AM on October 10, 2022
posted by primethyme at 9:14 AM on October 10, 2022
Do you have anything with rechargeable batteries that sits on a charger when not in use?
posted by sara is disenchanted at 10:02 AM on October 10, 2022
posted by sara is disenchanted at 10:02 AM on October 10, 2022
And when you say they checked the outlets, they removed the covers and took a look see at the connections and wires?
posted by sara is disenchanted at 10:05 AM on October 10, 2022
posted by sara is disenchanted at 10:05 AM on October 10, 2022
Response by poster: They checked the outlets with a thermal camera and by plugging in a device that checks the outlet. My husband and I used a different iteration of the later device and also sniffed all the outlets. We've checked _all_ our devices but especially the ones that could have large capacitors. Everything is working.
posted by miscbuff at 1:38 PM on October 10, 2022
posted by miscbuff at 1:38 PM on October 10, 2022
Response by poster: We eventually found the source of the smoke. After the incident we had switched to our steam radiators and so kept using that as heat. Our area had an unusual heat wave in November and we turned off the heat and turned on the AC (same HVAC that was suspect originally but inspected by both HVAC professional and electrician and pronounced fine). It worked great until suddenly there was a loud hum/vibration and a slight burning smell. We could hear the AC hum but it was not running. The blower fan was getting stuck when it cycled on (which is why the problem wasn't obvious when the electrician set the heat to 80 and let it run continuously for hours). It has now been replaced.
posted by miscbuff at 4:45 PM on December 22, 2022 [2 favorites]
posted by miscbuff at 4:45 PM on December 22, 2022 [2 favorites]
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posted by If only I had a penguin... at 9:20 PM on October 9, 2022 [9 favorites]