Learn how to prevent mold and mildew from growing in air ducts. Find out how a whole-house air conditioner can help eliminate mold and mildew in ducts and vents.
LESLIE: Judith in South Carolina has a question about mildew . What can we help you with?
JUDITH: Hi. I was wondering about mildew in the venting. We have a heat pump; 16-year-old house; coastal area. So we have a lot of humidity.
JUDITH: And we had the vents cleared, oh about a year ago and we seem to have a lot of dust. So when he did that he said that he saw a bit of mold , mildew back in one area so he would spray for that and that should help control that. We did notice, in our bedroom in the closet more indication of that. We took the vent cover off and it had mold or mildew on it and so we used alcohol. We’re kind of leery about using a Clorox-based solution to clean the inside of a vent that we could see. But really, what should we do? Because obviously it’s like an artery. If you’re carotid artery is clogged you know the rest of the system has some problems. (Tom and Leslie chuckle)
TOM: And you’ve had the ducts cleaned?
JUDITH: We did.
JUDITH: And you know, I think it blew a beer can out and some dust and a bit of that. But that’s all that we saw.
TOM: Well, you have to remember that with the metal ducts you’re not going to have mold grow on the ducts  because it’s – they’re not organic. But what does …
LESLIE: It’s going to grow on the dust.
TOM: It’ll grow on the dust. Exactly. So, cleaning the dust – cleaning the ducts and cleaning the dust off the ducts is the best way to get rid of that.
The other thing that I would suggest is to put in a high-quality electronic air cleaner  like an Aprilaire electronic air cleaner. I think it’s Model 5000, which is incredibly efficient; even picks up virus-sized particles. But in terms of cleaning that, generally we recommend a bleach and water solution. I don’t know why you’re hesitant to use that but, you know, simply – I would say about two parts, three parts bleach to about seven or eight parts water. It’s going to do a good job at killing any mold spores that are left behind or any mildew that’s left behind in that area. So if you see it, I would just spray it down and wipe it out and put in a good-quality electronic air cleaner. That will keep it clean all year long.
JUDITH: OK. We do run – when we built the house we were advised that we would need a humidifier.
JUDITH: That we – we really do find we do need it or else we have problems with noses and throats …
JUDITH: … and everything. But we just use a small cool-air vaporizer that we used for our children when they were growing up.
JUDITH: And so we do put some moisture into the air, but not a lot, during the wintertime.
JUDITH: Do you think that’s exacerbating the problem?
TOM: Not at all. Nope, not at all. What I would suggest you do is put on a good-quality electronic air cleaner and just scrub the air. You will see a marked difference in the quality of the air in the house if you put on a good-quality electronic air cleaner.
LESLIE: And you’ll also notice you’re feeling better.
JUDITH: Right, OK. And you recommended this Aprilaire 5000?
TOM: Aprilaire. Yep, Aprilaire Model 5000. Good unit; not too expensive; can be installed by your local heating and cooling contractor.
JUDITH: OK, and that’s where I should start …
TOM: Yep, absolutely.
JUDITH: … looking for that?
TOM: Yes, call your local heating contractor. Ask for the Aprilaire. Their website is Aprilaire.com . You can read more about it there.