Loose or leaky air duct diagnosis and repair questions and answers.

This article series describes the effects of and how to find & repair blocked, clogged, crimped, loose or leaky air conditioning or heating ducts, leaky air duct connections, defective heating or cooling ductwork.

The photo at page top shows what happens when cooling ducts are poorly connected through a crawl space.

HVAC Duct Leak FAQs

These questions and answers about HVAC ductwork air leaks, blockages, or sizing problems were posted originally

at AIR LEAKS in DUCT CONNECTIONS or

at AIR LEAKS in RETURN DUCTS or

at AIR LEAKS in SUPPLY DUCTS -

be sure to check out the HVAC duct air flow troubleshooting and repair suggestions on those pages.

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Should the installer have notified me about the bad leaks in our HVAC ductwork?

@InspectApedia-911, I'm working on the dry out/clean out of the crawl space. It's not been a picnic either since it's literally a "crawl" space. Thank you for your OPINION.

The "savvy contractor" should never have been hired. Lesson learned. I'm going to do as much as i can myself as far as sealing up the HVAC and everything else. This was major money not just a AC unit. new plumbing, drain pipes, and much more... I apologize.

This site is a well of information and im putting myself to the test. I'll call a Professional in if i hit my wall .... thanks again.

Huge gap where the main airflow comes into the ductwork

@ years ago(ish) we had new ac/heat pump installed on our home. Here just recently , we were having issues with some other things, and I had to go into the crawl space to look for said problem and noticed that ,among other things, theres a huge gap under where the main airflow comes into the ductwork .

the penetration hole i guess its called. the sheet metal that forms the "trunk" (outside) has metal tape and screws. but there are clearly gaps where it is not sealed. 100 degree temps outside and my crawlspace was comfy cool.

So Metal trunk sweating... dripping,.. 6 inch i believe off shoots to the vents insulation , soggy diaper type feel ... rusty register or vents into the house.

My questions.

Should the installer have notified me about the conditions of ductwork?

Wouldn't inspecting those for new unit be required? or included ?

I even asked if the ductwork was in good shape or not while they were here doing the install and was told "everything is fine" 2 years .

Is there any recourse ? i have a lot of work to do because of this and other poor work ethics... mold,... this is second unit in 2 years. or less. I can add images if it will help. On 2022-09-13 by Brant F.

by InspectApedia-911 (mod) -

@Brant F.,

"should have" and "obligated to" lead us into mincing words.

In my OPINION, a savvy installer of HVAC equipment inspects all accessible parts of the system so as not to be blamed later for problems not their fault and also to be able to tell you what work is needed for the system to work properly.

But let's focus on what you need to do:

have the duct system inspected and repaired or if necessary in some sections, replaced.

review the conditions in your crawl space and search this website for advice on CRAWLSPACE DRYOUT if needed.

 

Shouldn't the HVAC ductwork be sealed?

My new sublet had a ton of dust accumulate in a few weeks so I checked the filter and found a weird flexible duct setup leading to a wooden box that feeds directly into the AC unit. The box & unit are in the garage, and the box is not sealed.

There was a lot of dust & debris in the intake flexible duct, and I can see a piece of wall protruding out into the air stream path.

Also, there's a duct flap that was hanging open where the cold air returns to the vents. I propped it closed with a board because it was drawing in garage air. My concern was for carbon monoxide, dirt, etc.

Shouldn't this be sealed? Is that "duct box" proper? That portion of wall hanging down also seems wrong, like it's gonna suck out dirt from behind the walls & send it airborne. I have breathing problems as it is.

I hope you have time to answer these questions. I'll send the second picture separately. On 2021-07-30 by GadgetGirl -

Also, this flap was hanging down on the air vent that heads up to the living space. Shouldn't this be sealed?

by inspectapedia.com.moderator - return air path needs to be through clean space

@GadgetGirl,

That may be a slot into which an air filter was to be inserted; ask your service tech to take a look.

Where are the air filters for your system?

Looks like an "upflow" air handler - the blower is designed to move return air in at the bottom of the unit and out at the top.

So someone built a "box" to give a way to connect the return ducts to the air handler's bottom inlet. That design is in concept, correct.

But the return air path needs to be through clean space, not a space contaminated by piles of dust, debris, or whatever;

If that's your situation that area needs to be cleaned, and maybe, if there were rodents, disinfected, and the blower fan itself cleaned.

It is normal to see house dust in the duct system, and good practice to clean that system when it's dirty;

It looks as if the design isn't great - airflow is partly blocked.

Ask your HVAC tech to measure air supply and return flow to assure that it's adequate.

Question: asbestos paper tape on air ducts

I just today discovered that the white tape holding my heating ducts together in my 1940 New Westminster home was asbestos. It appears to be in good shape.

There is none of the white tape on the return air ducts. Should I just leave it? Or is there a hazard I need to deal with?
Many thanks for your help.

Best regards, Jonathan jonathan@baylis.ca 604-375-6570 (Jan 21, 2015) Jonathan Baylis

Reply:

Jonathan

Since supply ducts are under positive pressure (blowing out) it is not highly likely that asbestos from the paper tape wrapping duct joints will be entering the heating system air stream as long as the asbestos paper is left intact and undisturbed.

You can reduce the chances of disturbing the external asbestos paper duct joint paper by using a sealant paint.

When you are ready to remove the material the least costly approach is to remove the entire duct sections and replace them. Most people don't feel rushed to take that step.

See ASBESTOS DUCTS, HVAC for details.

 

Question: who fixes HVAC ducts that became disconnected

I had my ducts cleaned the other day and the man found that my heating and air conditioning ducts have come loose from the furnace from being stretched. Who fixes this? (May 15, 2015) Mary Loar

Reply:

In my OPINION re-connecting and securing HVAC ducts could certainly be part of the job performedf by an HVAC duct cleaning company.

If the cleaner isn't willing to do what should be a trivial task one wonders if the operator is in a bit of a rush - which makes me worry about the thoroughness of the job. Offer to pay the tech for the extra time needed to do the job right.

 

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Continue reading at AIR LEAKS in DUCT CONNECTIONS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

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• ENERGY AUDIT STANDARDS for ENERGY RATINGS - how HVAC system air leaks are measured & quantified
• RETURN AIR, INCREASE
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Suggested citation for this web page

AIR LEAKS in DUCTWORK FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to HVAC DUCT SYSTEMS

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