Central AC and mold

We've got central AC with the blower in a closet in the house. Recently we noticed that where the ductwork heads up into the attic it's all turning black and looks like it may be mold. We had one AC guy tell us it would cost over $1000 to clean up.
Is this correct? I don't want to fall victim to a scam. Can we take care of this ourselves?
Thanks for the input.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Is the black on the inside of the duct or on the outside? And is this sheet metal duct?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
It's on the outside. Runs from the top of the blower to the ceiling. I'm guessing sheet. It's like a stiff insulation blanket. Thanks.
Hi Ho Silver wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
To clarify, it's not sheet metal (at least what's visible). It's on something like an insulation blanket aroung the duct.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

This is Turtle.
If it is on the ouitside of the duct work. You being scammed. If this Mold is on the inside of the duct it could cost to get it out.
TURTLE
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
So I need to pull apart the duct work to check?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Use liquid detergent in water to wash the outside of the duct (insulation). If it is less than 10 square feet that is all you need to do. You can add a little clorox if no one in your house is sensitive to the smell.
The real problem is that mold is a moisture problem. Why is there moisture on the outside of the duct? Is there air leakage around where the duct goes through the ceiling? Do you have a roof leak dripping down on the duct in the attic? Is your blower speed set too low? Do you have a dirty air filter restricting air flow. Do you have a restrictive h(high efficiency) air filter? Are you running exhaust fans constantly, which pulls humid outside air into the house to replace the air you exhaust out? Are you running your indoor blower on continuous - that will increase your indoor relative humidity 10 to 15%. Do you have an oversized AC? Do you have a plumbing leak? Do you have a damp crawlspace or basement?
Finding out where the moisture is coming from requires answers to these questions and more and requires a compentent tech. You have to look for one of those, most techs have no clue when it comes to humidity! If you clean up the mold and don't fix the moisture problem, the mold will just come back!
Good luck
Stretch
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

What's to take care of? Do you have any evidence that this is harming you in any way? The planet is covered in mold.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.