What's Your Opinion on Duct Cleaning?

[2manyrocks]

I am not the only one skeptical about whether there are any real benefits to duct cleaning. Should You Have the Air Ducts in Your Home Cleaned? | US EPA

Would also say that a magnified view of dust particles from a bore scope might tend to blow them out of proportion, too.

 

[jaxs]

There's no shortage of opinions so I'll reserve mine and state a few facts instead.
#1 If supply ducts are dirty your filters aren't working.
#2 If supply ducts are dirty the evaporator coil is caked,100% guaranteed.
#3 They can spit shine ducts but if coil isn't cleaned you were scammed.
#4 You can retrofit a first class filter rack much cheaper than cleaning ducts and good filtration pays for itself several times over in efficiency and extended equipment life. Not to mention there will be no need to clean ducts nor coils going forward.
#5 I wouldn't allow metal duct to be coated inside if it were free.
#6 Whoever has 2 labs in house and can see through filter when changed once per year. One of two things is wrong,intake duct has leaks or air is finding a way to detour around filter. Hair is only half the equation , constant movement keeps far more dust airborne than would be the case for two human occupants( ditto for 5 to 14 year-old kids)

 

[MossRoad]

A lot of times you'll know how bad your duct work is just by looking at the squirrel cage on the on the blower motor. If Those fins are caked with dust / dirt, your duct work is most likely caked with dust /dirt as well.. It's best to have all the cracks and seams sealed up on the return side before the furnace / AH.
The best thing you can have done to the supply side is to have new duct work installed and have the insulation on the outside of the supply duct.
Dust particles in the home is possibly coming from the insulation fibers braking down inside your supply duct, and being blown inside the home.

I used round duct here and it's insulated on the outside with metal supply duct also insulated on the outside. and of course, all seams are sealed with mastic, and or tape .

What are these insulation fibers you speak of?

All we have is 6" round metal ducts going to each floor register in the house. 9 of them.

In several places around the house there are floor mounted air returns. 3 of them. Those are just space between floor joists with a metal sheet nailed up to the bottoms of the joist. So 3 sides wood, 1 side metal. Anywhere they have to go across the joists, there's rectangular metal ductwork hanging below the joists.

No insulation on anything or in anything.

 

[MossRoad]

A lot of times you'll know how bad your duct work is just by looking at the squirrel cage on the on the blower motor. If Those fins are caked with dust / dirt, your duct work is most likely caked with dust /dirt as well.. It's best to have all the cracks and seams sealed up on the return side before the furnace / AH.
The best thing you can have done to the supply side is to have new duct work installed and have the insulation on the outside of the supply duct.
Dust particles in the home is possibly coming from the insulation fibers braking down inside your supply duct, and being blown inside the home.

I used round duct here and it's insulated on the outside with metal supply duct also insulated on the outside. and of course, all seams are sealed with mastic, and or tape .

Oh, and yes, several years ago the fan went out, I pulled it and found it filthy. I cleaned it and replaced the motor. That's around the same time I ditched the electrostatic air cleaner. It's been pretty clean ever since.

 

[kenmac]

What are these insulation fibers you speak of?

All we have is 6" round metal ducts going to each floor register in the house. 9 of them.

In several places around the house there are floor mounted air returns. 3 of them. Those are just space between floor joists with a metal sheet nailed up to the bottoms of the joist. So 3 sides wood, 1 side metal. Anywhere they have to go across the joists, there's rectangular metal ductwork hanging below the joists.

No insulation on anything or in anything.

Main duct work is usually insulated on the inside. your run supply to each room is either flex, or metal insulated on the outside. I have never known of round metal supply run outs to each room insulated on the inside.
Some older homes had square metal supply ducts to supply each room, and I've seen some insulated on the inside, and some not.
It doesn't sound like your return is insulated on the inside like they have been for the last 50 yrs ?.

If you have square main supply duct, and if it's insulated on the inside, When your blower motor comes on, you're most likely getting those insulation fibers blown into your home. That insulation will begin to come apart over the years and ends up in your home where you're breathing those fine fiberglass fibers.

If you have your main duct worked cleaned, all your doing is stirring up those insulation fibers more, and possibly causing more of the insulation to come apart inside your duct work

 

[kenmac]

Oh, and yes, several years ago the fan went out, I pulled it and found it filthy. I cleaned it and replaced the motor. That's around the same time I ditched the electrostatic air cleaner. It's been pretty clean ever since.

if your squirrel cage is clean. your filter is doing it's job of containing most of the dust and dirt being sucked back through the return and re distributed in your home. Of course your A/C will catch some of it, but after the A/C coil there's nothing but duct work and insulation and nothing to prevent those insulation fibers from being blown into your home. Unless you have a filter in each register, which you can purchase for each room

 

[MossRoad]

Main duct work is usually insulated on the inside. your run supply to each room is either flex, or metal insulated on the outside. I have never known of round metal supply run outs to each room insulated on the inside.
Some older homes had square metal supply ducts to supply each room, and I've seen some insulated on the inside, and some not.
It doesn't sound like your return is insulated on the inside like they have been for the last 50 yrs ?.

If you have square main supply duct, and if it's insulated on the inside, When your blower motor comes on, you're most likely getting those insulation fibers blown into your home. That insulation will begin to come apart over the years and ends up in your home where you're breathing those fine fiberglass fibers.

If you have your main duct worked cleaned, all your doing is stirring up those insulation fibers more, and possibly causing more of the insulation to come apart inside your duct work

Ahh. Thanks.

No. We don't have any insulation on or in the 6" round ducts to the room floor registers, or any insulation inside or outside of the returns in the joist spaces or rectangular ducts.

No flex pipe anywhere.

House is 100 years old. Furnace is at least 35 years old.

 

[MossRoad]

Ahh. Thanks.

No. We don't have any insulation on or in the 6" round ducts to the room floor registers, or any insulation inside or outside of the returns in the joist spaces or rectangular ducts.

No flex pipe anywhere.

House is 100 years old. Furnace is at least 35 years old.

Just searched an old thread and found our furnace was installed in 1984. Armstrong. So 40 this year.

 

[Topzide]

I have a filter in the return grate and another at the HVAC unit. The grate filter tends to catch most of the "crap" before getting to the unit, where the other filter lasts 2 - 3 times longer. The ductwork has stayed clean. Have access hatch to keep an eye on it.

 

[ponytug]

FWIW: Putting filters on the distribution registers or grilles does add significantly to the fan back pressure, and that degrades the heating and cooling performance. Back pressure also increases losses from any cracks, or poorly sealed joints in the ductwork, further degrading performance.

I think of register filters as a temporary solution, e.g. while ducts are being cleaned, rather than something that is desirable longer term.

Intake/return filters are a different story in my mind. I have noticed that over the years the filter quality (e.g. MERV) keeps improving (creeping up), but dropping in a higher performance filter in an older system may mean the fan speed needs to be adjusted to maintain the heating/cooling system effectiveness. I'm all for better filtration in the interest of health, but sometimes, it is not simple.

We have an indoor air quality (particle) monitor that has helped me tracked down leaks, and when to turn on portable air filters.

All the best,

Peter

 

[MossRoad]

FWIW: Putting filters on the distribution registers or grilles does add significantly to the fan back pressure, and that degrades the heating and cooling performance. Back pressure also increases losses from any cracks, or poorly sealed joints in the ductwork, further degrading performance.

I think of register filters as a temporary solution, e.g. while ducts are being cleaned, rather than something that is desirable longer term.

Intake/return filters are a different story in my mind. I have noticed that over the years the filter quality (e.g. MERV) keeps improving (creeping up), but dropping in a higher performance filter in an older system may mean the fan speed needs to be adjusted to maintain the heating/cooling system effectiveness. I'm all for better filtration in the interest of health, but sometimes, it is not simple.

We have an indoor air quality (particle) monitor that has helped me tracked down leaks, and when to turn on portable air filters.

All the best,

Peter

I remember my grandma had what appeared to be cheese cloth over the registers in her house. Every time the furnace came on, they'd puff out a bit. I bet I was only 4-5 years old with that recollection.

 

[EddieWalker]

I haven't read all the replies. I'm not an HVAC expert. I am a home remodel and repair contractor.

Unless there is an obvious need, cleaning ducts is a scam that doesn't accomplish anything.

Cleaning the grills on the inside of the unit is worth the money, especially if you have pets. Hair gets through the filter and clogs the grill, which causes the unit to work harder.

It's very common to find a duct in the attic with holes it them, or even split where they join with another duct. An inspection of the ducts in the attic would be worth the money. That can also be the reason a duct need cleaning.

Because I have large dogs that shed a lot, we switched to a 2 inch thick filter. In my case, the 1 inch filter was bending at the edges and allowing dog hair to get past it. The thicker filter fits tighter and doesn't allow any air to get around it.

Probably the biggest mistake most of my clients make is to not add bleach to their drain line when they change their filter. I change my filter once a month. I have a gallon of bleach sitting next to my unit, and when I change my filter, I pour about a shot glass of bleach into the drain. Maybe a little more, I'm just estimating when I pour it in there. A gallon will last me years.

They also don't inspect under their unit. I see this in attic units the most. There will be standing water in the pan under the unit and the water is draining through the secondary line. Once the secondary line clogs up from what grows inside the pipe when bleach isn't added, the pan overflows and their ceiling develops water stains. This is usually when I get called in to fix their ceiling.

 

[paulsharvey]

So, I have never done it, but I know rework electricians and plumbers that would cut a hole in the duct to give them some cold air while working in the 130 degree attic. The better guys would slap some tape over the hole on the way back out, but I don't think most would bother.

 

[bdhsfz6]

Buy a cheap inspection camera for your smartphone like this one:

https://www.amazon.com/Endoscope-Semi-Rigid-Adjustable-Waterproof-Inspection/dp/B0D8W215CX/ref=asc_df_B0D8W215CX?mcid=33fba94efcee3a06b80a1e5b7ccc318b&tag=hyprod-20&linkCode=df0&hvadid=693071814466&hvpos=&hvnetw=g&hvrand=395175774695417520&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9058761&hvtargid=pla-2367976404208&psc=1

I have one and it works amazingly well. Use it to inspect your ductwork in various places. If they're dirty, get them cleaned.

I worked in an office back in the 1980's where half the employees smoked. People began getting respiratory problems and the company eventually had the ductwork inspected. I happened to see a worker when he opened up a section and I almost lost my lunch! It had a half inch thick coating of green gray mold coating the entire duct! They closed the office for 3 days while the ductwork was cleaned, and in some cases, replaced.

I doubt residential ductwork would ever get this bad but it might be worth spending $16 for the above camera to be sure.

 

[MossRoad]

I haven't read all the replies. I'm not an HVAC expert. I am a home remodel and repair contractor.

Unless there is an obvious need, cleaning ducts is a scam that doesn't accomplish anything.

Cleaning the grills on the inside of the unit is worth the money, especially if you have pets. Hair gets through the filter and clogs the grill, which causes the unit to work harder.

It's very common to find a duct in the attic with holes it them, or even split where they join with another duct. An inspection of the ducts in the attic would be worth the money. That can also be the reason a duct need cleaning.

Because I have large dogs that shed a lot, we switched to a 2 inch thick filter. In my case, the 1 inch filter was bending at the edges and allowing dog hair to get past it. The thicker filter fits tighter and doesn't allow any air to get around it.

Probably the biggest mistake most of my clients make is to not add bleach to their drain line when they change their filter. I change my filter once a month. I have a gallon of bleach sitting next to my unit, and when I change my filter, I pour about a shot glass of bleach into the drain. Maybe a little more, I'm just estimating when I pour it in there. A gallon will last me years.

They also don't inspect under their unit. I see this in attic units the most. There will be standing water in the pan under the unit and the water is draining through the secondary line. Once the secondary line clogs up from what grows inside the pipe when bleach isn't added, the pan overflows and their ceiling develops water stains. This is usually when I get called in to fix their ceiling.

What's this drain line you speak of?

The only drain we have is about a foot long from the air conditioner A frame down to a little giant pump that pushes that out into the flower bed in summer. All that is in the basement.

Is this a SW thing with HVAC in the attic?

 

[kenmac]

What's this drain line you speak of?

The only drain we have is about a foot long from the air conditioner A frame down to a little giant pump that pushes that out into the flower bed in summer. All that is in the basement.

Is this a SW thing with HVAC in the attic?

talking about the condensate drain , or your condensate pump.

there are a lot of HVAC systems installed in the attic here.
No where else to put it with a slab built house

 

[EddieWalker]

What's this drain line you speak of?

The only drain we have is about a foot long from the air conditioner A frame down to a little giant pump that pushes that out into the flower bed in summer. All that is in the basement.

Is this a SW thing with HVAC in the attic?

On every indoor system that I've seen, there is a white PVC pipe that's sticking straight up, or has a T in it that's pointing upwards. Usually there is a cap over it. The cap is never glued on, it's just a dust cover. You take it off and pour bleach in there. I do it monthly.

One of the big things that AC unit does is remove humidity from the air inside the house. That humidity becomes water inside the unit. It drains through that pipe. The pipe goes from the bottom of the unit to a sewer line. In attic units, it usually connects to a vent line.

The secondary line goes from the pan in attics. A lot of units in hallways don't have a pan, or secondary line. The attic line usually comes out of a soffit, dead center over a window so you can see the water coming out when the main line is plugged. Clients tell me that they have been seeing water dripping in front of their window for years, but never knew why. Then one day, their ceiling falls in, soaked with water and I get the call to fix it.

AC guys seem to like to put the units in attics because it gives them more flexibility on ducting. Also, a lot of attics have more room in them then a hall closet. When I built my parents house, I hit a wall with several AC companies about putting the unit in a utility area in the garage. They refused to do it. The one I hired agreed to put it where I wanted it. Servicing them, like adding bleach to the drain line is a horrible thing to do here in the middle of Summer. It also ruins your insulation because there is a path that you have to take to get to it. I've had clients hire me to build a plywood path to get to their AC units, with railings.

If your house has the older metal ducting, odds are very good that it's leaking in multiple areas. If it's the new insulated, flexible ducting, the only place I've seen it leak is where they join together, or Y a big line into 2 smaller lines. Most of the time I can fix it with some foil tape. I only notice it when I'm close and I can feel the cold air coming out through the leak.

 

[MossRoad]

Thanks for the explanation. I only know of one slab house around here, and its HVAC stuff is in a closet. One of our kids a couple hours south of us is renting a slab house. Their's is in the garage. Our other kid lives in an apartment complex. Her's is in the closet and is sitting in a drip pan.

 

[ponytug]

On every indoor system that I've seen, there is a white PVC pipe that's sticking straight up, or has a T in it that's pointing upwards. Usually there is a cap over it. The cap is never glued on, it's just a dust cover. You take it off and pour bleach in there. I do it monthly.

One of the big things that AC unit does is remove humidity from the air inside the house. That humidity becomes water inside the unit. It drains through that pipe. The pipe goes from the bottom of the unit to a sewer line. In attic units, it usually connects to a vent line.

The secondary line goes from the pan in attics. A lot of units in hallways don't have a pan, or secondary line. The attic line usually comes out of a soffit, dead center over a window so you can see the water coming out when the main line is plugged. Clients tell me that they have been seeing water dripping in front of their window for years, but never knew why. Then one day, their ceiling falls in, soaked with water and I get the call to fix it.

AC guys seem to like to put the units in attics because it gives them more flexibility on ducting. Also, a lot of attics have more room in them then a hall closet. When I built my parents house, I hit a wall with several AC companies about putting the unit in a utility area in the garage. They refused to do it. The one I hired agreed to put it where I wanted it. Servicing them, like adding bleach to the drain line is a horrible thing to do here in the middle of Summer. It also ruins your insulation because there is a path that you have to take to get to it. I've had clients hire me to build a plywood path to get to their AC units, with railings.

If your house has the older metal ducting, odds are very good that it's leaking in multiple areas. If it's the new insulated, flexible ducting, the only place I've seen it leak is where they join together, or Y a big line into 2 smaller lines. Most of the time I can fix it with some foil tape. I only notice it when I'm close and I can feel the cold air coming out through the leak.

@EddieWalker no criticism of your work, but I don't get the attraction of attic HVAC installs in Texas.

I am aware that attic installs are very common in your neck of the woods. For one, it simplifies ductwork, and if the attic is a conditioned space, it isn't too bad from an energy perspective, but I've seen a bunch of homes with AC evaporator units and ducts in unconditioned attics. They are hard to service, aren't energy efficient, and are a complete production to replace the evaporators on when the AC is replaced. Plus there is the vibration issue from the fans being right over bedrooms, and the perennial risk of the drain lines clogging and taking out ceilings.

Personally, I just don't get the attraction of attics as an HVAC installation location... I would take a closet on the slab, or adjacent to the main slab any day of the week. Flooding my lawn with a bit of condensate is cheap.

All the best,

Peter

 

[HawkinsHollow]

OP here. I just wanted to do a follow up on the duct cleaning we had done after our renovation. I am officially a believer. I just changed the filter after about 4 months and it looked really good. Before the duct cleaning only after a month the filter would be awful, thick visible layer of dust. The one I just changed after 4 months looked really good. Sure it was gray but there was not a pile of dust on it like before. And the air quality is just better. My wife has respiratory issues and she has not had any flair up since moving back in. Put me in the believer category.