How to Seal Leaky Ductwork | Ask This Old House 

You know it's getting serious when Richard clips his glasses together! That's some pretty cool tech!

I hope to see this become code with all new forced air systems. Once the whole system is installed, do this procedure as part of the process.

Awesome information. I was wondering if my duct work was in good shape. I got this place this year and the duct work was put in around 1974. I have already done some work to seal the Duct work. After seeing this I know to take a closer look and return and supply duct work. Thank you so much for this video.

It’s just latex and ammonia to seal the holes. It’s a great system with a great explanation.

3:40 Those glasses are slick.

Very informative , just good information, great video.

Good Tech. More people need this info.

The first problem you had was having a bunch of ducks working on your house. Never hire a duck.

Don't worry about breathing it in. If there are leaks in your breathing tubes/lungs, it will seal it too. :D

outstanding great work y'all

Had this done at my townhouse. It really works great. I'll be doing the samething at my new home.

Never knew this technology existed. How cool

Neat system.

Ran hundreds of High Bill Complaints for the gas utility in St Louis, Missouri & I can tell you first-hand this service boils down to ductwork in unconditioned areas and ductwork in conditioned areas. For ductwork in unconditioned areas this service can be advantageous.For ductwork in conditioned areas such as basements or inside soffits there is very little advantage and in some cases big disadvantages. I had a customer that actually had a reduction in basement heat ,much like this installation & the water pipes froze one cold winter night ( I believe the Insurance Company for the duct sealing service picked up that bill).

I'm glad I live in a ranch style home, all my mechanicals are accessible from the basement.

man that Rich T, what a down-to-earth and genuine guy. The whole TOH cast for that matter.

i find this video hilarious so ingenious

wow that's awesome

I’m in the process of finishing my basement on my new construction house and the hvac people didn’t seal any of elbows or connections for the supply pipes that go upstairs. They used uninsulated connector class for all the returns and the sticker on it says “for insulation in length not over 14’” all they used was a zip tie and a screw to connect to the upstairs registers. The stuff feels like cheap tin foil haha. All I wanted was to add a few supplies and returns to basement after removing the sheet rocked ceiling and found more work and stuff to be sealed!!

Amazing 😁

Do you guys do projects in San Antonio? I have a 1945 home with a new HVAC system that doesn't blow that hot of air. Looking closer it seems like they did a shoddy job and also hung some of the ducts to be off the ground. Is that normal?

Cool technology. Better check the fan static pressure before you do this. If the fan is already having to pump against high resistance on leaky duct what do you think the resistance will be once all the leaks are sealed? The key is properly sized and sealed ducts. Old ducts are notorious for being undersized

I've always wondered about something like this. My house was built in the late 60s. Anywhere a branch came off the main duct or return was massive leaks. I cut holes in the supply trunk and return wherever I knew ducts were coming in and out. I then sealed those branches with proper metal duct tape, duct mastic, or a combination of both. I then cut a larger piece of sheet metal to put over the hole, screwed it in and sealed it with more duct mastic. That helped quite a bit. There are still some areas I need to get to that I can't at the moment. Those spaces suffering the most that I can't get to, are above the garage.

Gotta love the voc's from that

I so want this done at my house. When I had the basement remodeled I specified foil tape because I didn’t know about mastic yet. They didn’t even follow that. This technique is the only way I know how to fix that annoying problem

I would like to see a follow up to this video about savings experienced over time.

If you have extra cash to help out contractors then it's nice gesture to call them and pay. If you are tight on budget, don't let contractor takes your $, your ductwork is fine and you don't need insulation. Hot air rises so if there are leaks it keeps your basement warm and will find its way to upper floors anyway. Or you buy a roll of aluminum tape for $5 and tape around the joints. But I leave it alone to warm up the cold water pipes down there so they may not get frozen by accident. Call the city and ask if the product is permitted with building codes and ask any contractor to apply for a repair permit with the city to protect yourself. Where I live, it's by law and the contractor I hired applied and paid for the permit like around $100 for furnace installation. The city sent the inspector over after it was done, he made the guy to come back next day to fix soddy work or license is suspended. That's how to protect yourself from cowboys especially with hot water tank or heating furnace.

Got the quotes for my 1700sqft house 3-4k LMAO LMAO LMAO

I'm really jealous of this basement.

I'm going to spitball here but in addition to all of this. I was a installer and every house we went to the "sales team" always had us install 4.5/5 ton condensers when the original ones were 2 tons. aprox 1500 sq/f houses.I dont work there anymore but school said never to do that and the company said it was "necessary"

The hole he drilled is still there lmao

I could care less about the rest of the video TBH. I just wanna know where to get those glasses you use when seeing the results of the pretest

4:49 your turn to talk there buddy.

I think the best way of preventing this in the first place is sit on the HVAC contractors that installed this in the beginning and make them use that duct putty and seal all the joints as they are installing them.

This is great! Can you tell me what this process is called and approximate costs for a 1200 sq ft home? Where or who do I call to have this done? Thanks.

Im curious would this work in a cement slap cold air return of clay tubing

New to me for sure.

It's like fix-a-flat for your duct work. And about as healthy to breathe.

Wow that was pretty amazing!

0:34 no outside the house 😂😂😂

Dont forget to drill a hole in the duct, so your basement looks like a Cheech and Chong movie while you're sealing...

I’m looking for more consistency in my outside temps. Any tips?

How can I seal this hose that was cut properly and contain whatever fiberglass strands are floating inside the woodwork of the cabinets once I sealed the cut aluminum hose that I cut properly with an airtight seal what should I do with the remainder of the cabinets should I put some type of cork sealantall over the inside edges of the cabinets to help air seal pretty much the entire cabinets structure. I also find it that when the stove is turned on

Should be titled: "How to pay someone else to seal leaky ductwork".

nice and love it!! So, how much??

how can we get more information on this service in our areas. What is the product being used?

Can it work for flexible insulated ducts?

That one the store was turned on the effect that it has on my allergies when I’m in the kitchen when the flame is on and there’s heat on the burner, he’s even worse. Does the heat make the particles of fiberglass sitting inside the woodwork lift Lift off more aggressively

Leaky Ductwork is Richard’s drag cabaret stage name.

What kind of VOCs are in the sealant?

What does this sealant do to the evaporator and heat exchanger? Or did they remove them from the airflow somehow?

What's this process called. That would be helpful. I dont know what to ask for when searching for a company to do it.

How much does something like this cost? I just got a new furnace and AC installed last week. None of my ducts are sealed or insulated. These are on the list of getting done as soon as I can!!

How much does a procedure like this cost? Also doesn't seem very safe to breathe that in at all!

so .. about that 4sqmm hole, can i get that back?

Does this company sell that equipment? After watching this video, I'm thinking it could be a good business startup...

What is this process called and did it ever catch on

Just wondering what something exactly like this would cost? I believe i really need this done as well!!

Can this system work in flexible ducts?

What is this product or procedure called???? I would like to look into this for my home in Mariposa Ca

Why can’t things just be installed right the first time? What a novel ideal.

Great vid! Are there any self seal duct connectors? We have people in our home that have asthma/allergic reactions with such products

what's the name of the system used to atomize the sealant into the homes ventilation?

wow

This is an infomercial for Aeroseal service. Innovative but pricey. Good reviews available online discussing effectiveness and payback time. Certainly makes no sense if you can reach most of your ductwork to seal with mastic from the outside.

Are there any precautions related to the sealant collecting on the coils or blower motor within the air handler? The system does seem very interesting and worth looking into.

5:37 nice that piece of sheet metal fell into the duct.

Is there a commercial LEED requirement to eliminate leakage in HVAC systems? That should become residential building code requirements ? Shortage of residential LEED heat pumps.

That's actually pretty cool! And what about all that airborn sealant myst that the guys were in. Isn't it dangerous?

So I’m assuming this doesn’t effect the evaporator coils or heat exchanger?

Do HVAC installers do this, or is it a specialized thing? I recently had a new furnace and new air conditioning put into my 1939 house with original forced air ducts, and I'm thinking I should probably get this done. My HVAC installers did not mention anything like this, but they did refer me to a duct cleaning service.

So what’s stoping the sealant from getting all over the a-coil and the blower????

Aeroseal would be the best option

When replacing an old round duct with a new round duct, it seems too tight to fit all the way. Can't get the last seem together.

How safe is it to breath this? thanks.

I look forward to seeing the “Did you develop cancer from duct sealant aerosol spray?” commercials as I’m falling asleep in 25 years.

How did they patch the hole?

Hi guys, I made a mistake of cutting a flexible HVAC house. It is the hose that runs on top of the kitchen range that is on top of the stove. It is the hose that runs from the range on top of the stove. It is this hose that runs up through the ceiling of the kitchen and part of it is inside the cabinetry that’s right on top of the kitchen range. So basically it’s there as the kitchen exhaust. The reason that I cut it is because below me there’s people that smoke a lot of pot and a lot of those films going to the kitchen. Those fumes going into the kitchen. One day I got fed up and I just cut the flexible aluminum hose if I can call it that in the middle. I went to seal the end with plastic and regular tape. After a while, I realize that the plastic blocking was not doing his job properly. I went to Home Depot and I asked the people that were there. What can I use the inside of the house to block the order that was coming out of there or the fumes. I was told to use something that looks like a beige colored foam material. I was told to stuff the inside of the pipe with that material. After installing it, I realize that the material might have been composed of fiberglass, such as the one that’s yours for attic insulation. I see all the ants again with a piece of plastic. I realized right away that my allergies in my eyes started burning. My nose started itching. My chest started to get tight. I suffer from allergies. The culprit in this is the fiberglass that was put inside the aluminum hose to block odors. I then went on to remove the fiberglass that was installed in there. But I am still having problems with burning eyes in the same symptoms that I describe earlier when I’m in the kitchen area specially. I tried cleaning the area with a shop vac and wore a 3 AM particle mask. I can’t seem to get rid of the problem. Every time I walk in the kitchen I get like that. I can’t think any other thing, but to think that some of the fiberglass strands flew inside the inner portion of the cabinets . So basically, there’s probably strands of fiberglass flying inside the woodwork of the cabinets. I find it to be particularly a huge issue on windy days and this I can only assume that the wind is blowing inside into that in their area like you know the roof of the house and lifting all those fiberglass particles that are sitting inside.

Will this help lower humidity levels in the house?

Use liquid nails always works great on duct work

Wow that return drop lol

What do I search for to have this done on my house

How much should this type of service cost ?

Whats the cost of such a service?

What is this called and how much would it cost?

I just had complete HCAC system, ask for the interior sealing, all the companies I called they never heard of this system. Hmmmm this call for an investment proposition ?

How does this system not get stuck in the evaporator or other components?

What’s average cost to have this done?

It's basically Elmer's white glue (poly vinyl acetate). The pump for the injector is a cole-parmer peristaltic pump. So with a blower and your kid's glue (or someone else's kid), and a little ingenuity, you can diy this whole thing.

6:37 can just imagine all that aerosol in their lungs!

One thing I didn't hear in this video was whether the duct work needs to be cleaned prior to sealing????

All of this makes sense but how do you know that material isn't toxic over time when heat is applied or over time it breaks down? Not comfortable not knowing what this material is made of.

FLEXTAPE!!!!!!!!!

How much does something like that cost?

Basically, using tubeless bicycle sealant for your ducts.

Very enlightening, but is the white glue liquid safe for our lungs?

I think flexible ducts are the way to go.

Nice video and helpful...for those with basements. We live in a townhouse. How do you find and repair leaks when you can't even see them because they are inside the walls?

Won't the basement be much colder now though, since much less heat is escaping in the basement ? I guess it's worth it to save money on heating bills, but that was never mentioned.

How does someone find a contractor that performs this type of sealing? It is not named in the video or description. Lots of people asking about cost but that would vary by contractor. Typically any reputable contractor would give an estimate at no cost though.