My duct work stinks! Help!


Premium Feather Member
11 Years
Mar 25, 2008
Where the temps. have cooled off here and I haven't ran my heat pump for the last several weeks, my vents / duct work is starting to stink. I'm guessing because of the condensation that built up and mixed with the dirt and muck inside the duct work and has now dried out. Is there anything I can do to make it smell better?
Last edited:
1st....thank goodness you were talking about your heat pump. I almost didnt open this

Have you thought about just running the pump through a cycle of air and then a cycle or 2 of heat just to clear it out? It might help some.

Good luck!
If it is just dust and such blowing out, just turn it on and leave the house for a while. If it is mold, I don't have any good suggestions except talk to someone who really knows what they are doing. That stuff can hurt you.
you can have them vacuumed.. either you or a professional.. also.. do you have the option on the thermastat to have the fan on "ON" instead of "auto" some do , some don't.. this will help keep the air moving everywhere.. Again.. if not, maybe someone could wire it that way for you.. and yes.. its easy..
I run just the fan for an hour or so, and spray Lysol in the intake vent. Makes the whole house smell better. And change the filter too.
I thought of a story that might interest you. A guy I once worked with was driving a van pool. The AC system started to stink and some of the passsengers complained. The next morning, on the way to work across the Lake Pontchartrain Bridge from Slidell, he sprayed Lysol into the air return. You can imagine what happened. The passengers came close to lynching him. He could not figure out what he did wrong. They complained and he tried to fix the problem.
Check at Lowes or Home Depot for a deodorizer sheet. It will be in the aisle with the HVAC products. They are about $3. You only need to hang the oepned package on the intake filter of your unit and let the system run. Be careful though, some of them are really strong! I suggest using the Vanilla. Just try cutting off a small piece of the outside packaging at first until you get to the strength that you want. They last for about a month or two.
We used to have a separate heat pump for a sun room on the back of the house, and the duct work for the sun room ran underneath it in an unheated crawl space. In the fall, condensation would form in the duct, and that in turn caused mildew to form. It was so bad one year that when we turned the heat pump back on, we had black stains forming on the vent cover on the wall. We ended up having to take the ducting down to scrub it out. Eventually, we re-ran the ducts, and we leave the fan running even if we are not heating or cooling.

I'd suggest scrubbing out your duct work, as you may have mildew. When spring and fall hit, and you're not running the heat or the AC, keep the fan running so that you don't have still air allowing condensation to form. The fan costs money for the electricity, but it's better than blowing mold or mildew into your house.

New posts New threads Active threads

Top Bottom