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Question DetailsAsked on 4/28/2017

have lite odor in bedrm, next to 6 air cond units outside window could this be freon im smelling

smelled it last summer, not so much in the winter, started smelling odor again and with air conditioners running it made me think that it might be freon, I only smell it in my bedroom, strongest on the wall wear units our placed outside.. its a stale lite odor but at times its to much to breath, any suggestion what it could be

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2 Answers


Freon itself has a minor light chemical solvent smell (I would say like ethylated alcohol or ether), but has lubricating oil and sometimes surfactant and anti-gelling compounds in it. Depending on brand, the odor has been described as like ether, chloroform, ethyl alcohol, and new mown grass that I have heard of. Other refrigerants than Freon can smell like solvents, or propane or ammonia if running those as a refrigerant gas. Some refrigerant gases use different types of oils like ester based which have unique chemical smells, but generally an oily or plasticy (is that a word ?) odor is what is complained about when they are leaking.

If you are smelling a freon (or other refrigerant) leak, for that large a leak likely would drain out within days to maybe a week or so - so if has been going for months and months, unlikely to be smelling strongly now - except I guess MAYBE if you are smelling the lubricating oil in the refrigerant and it sprayed out of a leak in the wall or such - if refrigerant lines run through the bedroom walls or floor. But when I have been working around A/C units (and refrigeration units) even with active leakage or bleeding off, I have never noticed more than a tinge of a smell - never overpowering even when there was or just had been a significant discharge within a couple of feet of me.

However, if one of the units has a refrigerant leak on the compressor or on a belt drive or fan motor, I would see that stinking pretty good when the unit qwas hot - but not likely in the winter.

Could also be hot compressor smell or a burning belt (for belt drive units), especially that if you hear a squeeling sound when the compressor first starts up.

Since you said you smelled it some in the winter (when A/C units presumably were not operating, I would guess more likely a mold or rot - maybe in the wall or flooring or attic.

When you smell it strongly, open the window (if breeze is from that side) or go outside immediately and smell around to see if stronger or not from that side. Also, smell around the A/C units to see if the smell is coming from them.

Could be any number of things - including moldy basement (yours or neighboring house), even smelly dumpster since you evidently live in apartment or condo unit.

Also commonly roof leak causing rot/mold in the attic, leaking pipe in bathroom or walls, leaking hydronic or steam heating system pipe, leakage around window frames causing mold in the walls.

Pay attention to which way the wind is drifting when the smell is strong - which could indicate if from outside or from in the walls (generally would be strongest when wind is toward that wall) or in flooring/subfloor (commonly strongest when wind is away from that wall).

Presumably, if a refrigerant leak of that duration, a pressure check on all the units (at probably around $25-50 per unit charge if all done at once) should tell if any unit is significantly low on pressure (hence, lost gas) - but presumably all the units are owned by the individual tenants if there are 6, so getting that coordinated and paid for would be a hassle at best if all were not owned by a condo association or homeowner's association or such.

One other possibility - if more of a sweetish but also stinky smell like dirty socks, could (depending on where the evaporator coils are) be "stinky sock syndrome" - bacteria and mold growing on the evaporator coils. But that smell (unless you have an air-to-air heat exhanger system, which is real unlikely) comes through the ducts. You could try taping plastic sheet over the ducts and see if that makes it go away. Solution to that is evaporator coil (and sometimes duct) cleaning, and for prevention ultraviolet light unit installation shining on the evaporator unit.

You can find a number of previous questions with answers about odors - a couple of sample links below - by putting the word "odor" (without the quotes) or "smell" into the Ask box - it will pop up a half dozen or so related prior questions related to house odors.

Answered 3 years ago by LCD



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Answered 3 years ago by Member Services

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