Earlier this spring, I was cleaning my house when I suddenly smelled skunk.
I have a much more sensitive nose than my husband, so when he couldn’t smell anything, I tried to talk myself out of it. Maybe someone had walked down the street smoking marijuana. Maybe a neighbor was outside smoking. But the smell persisted, and as I moved around the house, I became convinced it was strongest near my air vents.
That’s when my imagination went somewhere considerably less pleasant: What if an animal had gotten into the ductwork?
I went outside and inspected the air intake. It was elevated and screened, making my theory seem pretty unlikely. Within a couple of days, the smell disappeared, and I mostly forgot about it.
Then, a couple of months later, it happened again.
By this point, I had mentioned the mystery smell more than once, but no one else had actually smelled it. One friend even suggested that perhaps I should talk to my doctor, just to make sure the problem wasn’t my nose rather than my house.
Then one night my husband, Craig, and I were watching television when I smelled it again. I mentioned it, and within seconds he could smell it too.
“Is this what you’ve been smelling all along?” he asked.
Yes. Exactly that.
Now I knew two things: I wasn’t imagining it, and somewhere around our house there really was a skunk.
I started looking more carefully outside and noticed what appeared to be animal burrows beneath both the front porch and back deck. A few nights later, sitting on the back porch around 10 p.m., we finally met our visitor.
A young skunk, about the size of a small cat, emerged from the bushes and wandered around the yard. He was surprisingly cute. He was also the animal that had been digging up my plants and leaving their roots exposed. Eventually, he disappeared back into the landscaping and continued digging.
At least one mystery was solved.
But another remained: If the skunk was outside, why had I been smelling him inside the house, and why did the smell seem strongest near my air vents?
So How Was the Smell Getting Inside?
It turns out houses move a lot more air than most of us probably imagine.
According to the U.S. Environmental Protection Agency, most residential forced-air heating and cooling systems do not mechanically bring fresh outdoor air into the house. Instead, outdoor air enters homes in several ways, including through open doors and windows and through a process called infiltration.
Infiltration is simply outdoor air finding its way through openings, joints and cracks in walls, floors and ceilings and around windows and doors. Wind and differences between indoor and outdoor temperatures can help drive that movement.
In other words, outdoor air doesn’t need an open window or an obvious hole to get into your house. Whatever is in that air can come along for the ride.
That still left the question of why I had associated the smell so strongly with the vents.
Once an outdoor odor gets inside, a forced-air system can move that indoor air around the house. There is also another possible pathway in some homes: duct leakage. The U.S. Department of Energy warns that poorly sealed return ducts running through unconditioned spaces can draw in contaminated air and distribute it throughout a house.
Depending on where ductwork runs and where air is entering the structure, an HVAC system can potentially help move an odor whose actual source is somewhere else.
That doesn’t prove what happened in my house. We didn’t conduct pressure testing or inspect the duct system afterward, so I can’t tell you exactly which pathway brought eau de skunk into my living room.
What surprised me was realizing that smelling something at an air vent didn’t mean it originated there. The vent may have been the messenger rather than the source.
I had thought of my house as fairly closed to the outdoors when the windows and doors were shut. In reality, air was still moving between the two. The HVAC system was moving air inside the house, while wind, temperature differences and pressure changes could move outdoor air through openings I couldn’t see.
The skunk simply made that invisible movement very easy to smell.
Once we actually saw him, some other pieces fell into place. The Missouri Department of Conservation says striped skunks are common in urban and suburban areas and often shelter beneath decks, porches and sheds. They forage primarily at night, and during spring and summer insects and larvae make up an important part of their diet.
That explained why the spaces beneath my porch and deck were attractive real estate and why he spent so much time digging around my landscaping. Living across from a wooded lot may have made seeing a skunk less surprising, but apparently there was plenty on my own property to interest him.
My yard had amenities.
For several months, I had treated the smell inside the house, the holes beneath the porch and deck, and the mysteriously uprooted plants as separate little mysteries. Eventually, a small skunk wandering through my backyard connected them.
I started out wondering how a skunk could possibly have gotten into my air ducts.
What I learned instead was that he didn’t need to.
Karen Moeller
STLKaren.com
Karen.McNeill@STLRE.com
314.678.7866
About the Author:
Karen Moeller is a St. Louis area REALTOR® with MORE, REALTORS® and a regular contributor to St. Louis Real Estate News, helping clients make informed, data-driven decisions.
