Why a seller's own check misleads
When owners walk their house looking for odor, they usually do it on a normal day: windows cracked, the household moving around, the furnace cycling as usual. That is the least revealing condition there is. Buyers often see a house that has been closed up for hours, sometimes vacant for days, with closet doors open and the basement lights on. Air that sat still in a closed room is where odor concentrates.
Friends and family are a partial fix. Someone who visits often has adapted too, and close relatives tend to be polite. The listing agent is usually a better judge, because agents walk into many houses a week and are used to giving sellers difficult feedback. A pre-listing inspector or an odor assessment provider adds a further layer, since both are looking for the source rather than just the impression.
It also helps to name the odor precisely. 'Musty' points toward moisture in a basement, crawl space or behind a wall. 'Stale' or 'smoky' suggests residue on surfaces and in the HVAC system. 'Sewer' or 'rotten egg' points to plumbing, and rotten egg near a gas appliance means leaving and calling the gas utility or 911 before anything else.
How to stage an honest sniff test
Leave for at least a few hours
Go out for an afternoon so your nose resets. Ideally have the person doing the check arrive from outside, not from another room.
Close the house first
Shut windows and interior doors the evening before, and turn off fans, candles and plug-in fresheners at least a day ahead.
Run the system that matters for the season
In cold months, let the furnace run a full cycle. In summer, run the AC. Both move air out of ducts and soft surfaces.
Enter the way a buyer will
Front door first. Note the first impression in a single word before moving on.
Open what buyers open
Closets, the coat closet, under-sink cabinets, the laundry room, the basement stairwell and any crawl space hatch.
Write it down room by room
A short note per room makes it possible to compare after treatment instead of relying on memory.
Who to ask, in rough order of usefulness
- Your listing agent, asked to be blunt and to compare your house with others at a similar price
- A friend who rarely visits and has no stake in the sale
- A pre-listing home inspector, who may note odor along with moisture clues
- An odor assessment provider, who should identify sources rather than simply rate the smell
- A stager, who sees the house with furniture and soft goods in mind
- Yourself, but only after several hours away and with the house closed up
Common questions
- If I cannot smell it, does it really matter?
- Buyers and their agents can, and they tend to mention it in feedback or to the inspector. It is far cheaper to find out before the listing goes live than after the first round of showings.
- Should I ask the agent to check after every treatment step?
- A recheck after source work and again before photos is usually enough. Ask the same person each time so the comparisons are consistent.
General information for the Denver area, not a quote or professional advice. In an emergency, call 911.