Dust can be generated by lots of different indoor and outdoor sources including people, pets, pollen, pests, etc. (I ran out of p's.) Most homes operate at a slight negative pressure due to a combination of undersized return air systems and stack effect.

If your return ductwork is located in the crawl space and isn't well sealed, you can pull dust and contaminants into your HVAC system from the crawl space. The fix here is to seal joints in the ductwork with mastic or tape designed for that purpose and ensure the duct work is designed to return an equivalent flow rate of air to what the HVAC supplies.

With your windows and doors closed, your home is still subject to stack effect-- a chimney-like effect due to differences in air pressure, temperature and density inside and outside a home which will draw outside air into your home. With the windows and doors wide open, the differential is minimized. The fix here is to air seal your home to the extent practical with a focus on weather stripping of doors and windows.

Exhaust-only ventilation such as bath vent fans and range/cooktop vent hoods can depressurize a home and draw air in from outside. Depending on the exhaust flow rate, consider how make up air is supplied. If it's drawn through cracks in walls and around windows and doors, it's unfiltered. You may need a make up air system for your range/cooktop vent hood. The International Residential Code requires make up air be provided when the hood capacity exceeds 400 cfm.

I am having similar issues. Been in house two years. Summers have been very humid in house and I couldn’t breath. Just had my ducts cleaned to see if it would get better. Won’t know until next summer. Anyway they found some pretty big holes in my ducts and some not connected and filled with spray foam that had been put in by previous owners. They also determined that my main trunk had a large hole on the underside and was straight up fiberglass no lining in them. I think they called them JM board. My house is super drafty and some rooms are freezing. Duct people recommended to put a fan on AC in attic to circulate heat. We did that and it got warmer but I felt worse, I couldn’t breath again. So we turned the fan off and then I had this dust all over my house. Getting estimates now to replace the main trunks incase this is fiberglass. Not sure what it is but I guess I don’t want to take a chance.

Oh, that is bad if you're breathing fiberglass dust....

We aren’t sure but I scrubbed the house top to bottom before my kids came home from school. Washed all bedding and curtains. I have been a maniac. I had overnighted a fiberglass test kit and overnighted it back to the lab. Waiting on results. Fan is off and I haven’t seen anymore dust. Estimates to have the ducts replaced is pretty steep. But I have to do it. This expense wasn’t in my budget. I am pretty pissed as I think the home inspector should have caught some of this. He Didn’t see ducts not attached in attic. They were laying right there on top of the spray foam insulation. Not sure if I can make a homeowners claim as the humidity ruined my new hardwood floors. What a mess. Still need to do other important work in house that we knew about. Now I can’t. I just want to move. But where am I going - sell high buy high. Not in my favor. Sorry to hijack your post. Just wanted you to consider if that dust is dangerous. Or others reading the post.

You asked for advice so here it is. Screen contractors before hiring them. Discovering source of dust and remediation isn't difficult for trained, make that PROPERLY trained techs if alowed to work onsite. It's not so easy for interweb buds from 1k miles away. If you hired me then asked me to do what someone on the net advised I'd load up and leave.

"You asked for advice so here it is. Screen contractors before hiring them."

"If you hired me then asked me to do what someone on the net advised I'd load up and leave."

Uh...Someone on the 'net asking for some insight and what intelligent questions to ask when talking to a contractor doesn't deserve the snark. With that attitude, you wouldn't have to leave -- I'd show you the door first.

Do you actually need strangers telling you to ask for referances,insurance and license? Or do you mean intelligent questions like "do you know what you are doing", "can you locate the source of dust settling on things in a home"? By insight are you refering to instructions you can give contractor such as "someone on the web said I should require you to perform a blower door test and a duct blast"? You;ve already wasted money on some sweet talker that lacked skill,do you want to pay for more sweet talk or having problems solved? Suit yourself but an intelligent homeowner know's advice is worth what you pay for it.

"Do you actually need strangers telling you to ask for referances, insurance and license?"

Just because a company has references, insurance, and license doesn't mean they know what they're talking about.

"Or do you mean intelligent questions like "do you know what you are doing"

Seriously? Yea, like someone's going to come out to bid on a job and admit they don't. LOLLOLLOL!!!

"Suit yourself but an intelligent homeowner know's advice is worth what you pay for it."

Now you're just being insulting. I definitely would show you the door.

Is your indoor coil free from buildup?

"Is your indoor coil free from buildup?"

I got both new a/c and furnace in the late summer, so a new coil would come with the set-up, right? If that is not the case, then I'm not sure and is something I should check on.

There is plenty of misinformation provided from this website. There is the saying that goes to the tune of... "If it's on the internet, it must be true." Now there's been fact checkers brought into determining for your benefit or "theirs" that what is said is true or not.

Politics 101. This board has just as much politics to it as the US congress. So with that said...

A dust generation problem in a house as already mentioned is almost always a direct result of negative air pressure. Seems simple enough.... people that don't know the full scope of this problem will often tell you the problem is only due to leaking ducts...

Of which the fact checker in me, will tell you is mostly false. It's so easy to do this job... you hire a company, that company sends you a 20-30 something old kid. A builder would be no different in that scenario (contractual obligations, to put it bluntly).

When you HVAC system comes on, just due to design alone... can create the negative pressure you're trying to fix. IE: the whole house doesn't need to be under a negative pressure to create dust. --- Your HVAC system has duct work -- that dust can be strewn thru your house via the return and corresponding attached supply ducts. I like to call this GIGO. Garbage in = Garbage out. (design as it were)

System Design: the magic ingredient that determines how well or how poorly your system will work or not. In a world of people who say choose a brand name to fix a problem. Like Trane, Amer. Standard, Carrier, Bryant etc.

The conversation I have often goes like this: Hi, I am looking for quotes for new Trane system. Oh why have you chosen this brand? Well I am having alot of problems and I heard that Trane systems are good? Or I have this old Trane system that is still running... not realizing that was a time period in which most of that system was made in America. From now --- things are merely assembled here if that.

People do not stay abreast in changes made over the years of which are many to numerous to mention here. This comes from experience in actually doing these things. Many of the comments you get here are from those who do not do this proffessionally which Klem is trying to tell you "bluntly".

Those same people with an axe to grind will turn around and bash people like me as well as people like Klem.

mxk3 z5b_MI, you have to read alot of this stuff with the thought that someone like Klem is trying to help you. Tough love isn't help? There is plenty of misinformation on the internet, thru amateur advice and other sources. HVAC is a job in which "it looks easy" to many. But that doesn't mean it is.

One method how this can occur...

Another method how this can occur...

So there's only two methods how this can occur? nope.

I service the Katy, Texas area.

Government actions = Politics

EPA = Government (political) DOE = Government (political) Building Codes = Government (local level)

Much of what is allowed or disallowed is related to Government or Politics. So on that level there is no escaping it Charles. You of all people should know better.

Stack effect?

I believe I covered it when I said?

So there's only two methods how this can occur? nope.

See builders often like to read what they want and ignore the rest at the detriment of whom?

Plenty of info here for you to read "between the lines".

No where on this thread do I suggest this problem can be solved by opening a window. Builder trying to create what? Builder Grade info. Nothing new. His next response will be to change the argument to something new because he's lost this one.

"Tough love isn't help?"

There's tough love, then there's being insulting. There's a difference. Gee whiz, I'm just looking for some input on what might be going on, and I feel like I'm getting beat up for choosing the company I did. Ultimately I'm the one responsible for vetting and hiring a company, any company. This particular company put in the HVAC in my other house, the system and installation was stellar and I had not a single problem. Not one. Zip. Nada. So I took my own past recommendation. My complaint this time around and need for a call-back is about the temp difference between areas of the house - he did say if the problem still was present they could come back out and zone it in the future. I didn't want to pay the $5K extra the other company was charging for that work, figured I'd resort to that fix if needed. All that to say -- there's often much that goes into a decision, and insinuating that I'm not intelligent or don't know how to vet a contractor is insulting.

All of the companies mentioned that gravel could be the source of the dust and to get it covered, it wasn't just this company. That did not fix the problem.

Although, now that I re-read, maybe the barbs were aimed not at me but rather between "you guys" - ? IDK. I'm not a regular HVAC poster.

Anyway, I do appreciate the responses about what might be going on and the visuals are helpful for getting a grasp on negative pressure. I think what you all are saying is the dust may be being sucked in by a negative pressure situation, and that might be caused by leaky ducts - ? Or no?

Although, I wonder if there is residual gravel dust in the ducts that simply needs some time to work its way out of the system -- it's only been a week since I had the plastic put down over the gravel. ?

@mxk3 z5b_MI,

Pretty sure klem was taking aim at you. It happens.

With respect to residual dust on the gravel, if it's under plastic and the seams are overlapped and taped as they should be, you've really reduced the potential for that dust infiltrating your home. I'm betting you've still got good dust accumulations lodged in your underfloor insulation, on the plate, block walls, etc. And, assuming it's a vented crawl space, the open vents are a conduit for refreshing the accumulated dusts over time.

It would be a rare HVAC replacement contractor that improved the status quo of your existing ductwork. That's a good place to start. Another benefit of improved duct sealing will be more conditioned air going where it's intended to go. Might not fix the problem in the vaulted areas, but it should help.

Who would I call for specifically ductwork? You know -- the ductwork "experts". Is there such a type of company I can call? Perhaps getting the ducts cleaned again would be a good idea, since, let's face it, it's been 5 years of gravel dust floating around in there since I moved in - ?.

A competent mechanical contractor (they're rare, but they do exist) would be the one to seal your ductwork if your want to use mastic or UL-approved tape, but you could do that as a DIY, too. It's not particularly difficult. Another alternative is to hire a specialty contractor to seal the ducts from the interior using Aeroseal.

I'd like more info on your whole house filter system. It doesn't seem to be doing enough. Is it a media filter? What MERV level of filter are you using now. ? Is it showing any build-up? What size is it. 4". 6" 12" thick ridgid cell. Have you changied it?

Anyway, I do appreciate the responses about what might be going on and the visuals are helpful for getting a grasp on negative pressure. I think what you all are saying is the dust may be being sucked in by a negative pressure situation, and that might be caused by leaky ducts - ? Or no?

It depends, often times "settled dirt" is not the problem unless it gets stirred up regularly.

There is dust in the air already, dust in your home already. Could it be infiltration of outside air or is it problems with the design of your duct system? We can only guess when it comes to that.

IF your system is more or less running as a 'vacuum' it is drawing this air from where? Filtration is part of it, but not an end all be all solution with an improper duct system. As when it comes to dust settled on furniture, a filter alone is not going to alleviate that if dust is continually pulled to this area of the house.

WHY? your system runs / shuts off. Once the system shuts off the filter doesn't do anything.

If your system draws air, shuts off --- dust is heavy and will settle where ever it's drawn in path ends.

That said you could have a multiple of various things causing this. While a remote chance a good source of dust inside the home is your laundry room. The dryer vent system may have a problem. It may not...

If dust is drawn into a room via duct work design problems... the hvac system shuts off, that dust now settles. The system turns on again drawing more dust into the room. The hvac system shuts off, the dust settles.

This however, doesn't answer the question where the dust is coming from. It might just be normal dust in the house that gets pulled to this single area in the home or it could be a bigger problem.

------------------

A competent builder, they are rare... much of the time causing these issues only to be discovered years later after the "middle man festival" has ended... due to "contractual obligations" revolving around fine dining and fine accommodations. ~ They butter my bread. LOL. The argument as it turns out isn't a "ONE WAY" street.

"This however, doesn't answer the question where the dust is coming from."

I would consider the following two excerpts from the OP's posts to be really good hints:

"I live on a dirt road" and "I also suspect leaky windows -- I can feel the drafts, but then again the problem is worse when the house is shut."

Wall-to-wall carpet can generate, catch, hold, and send out an amazing amount of house dust. It is a problem in the family/TV room in our house that has it (the only room with no wood flooring). If you have it too, this might be the primary culprit and not the HVAC system.

Once the heat runs in winter, the air becomes more dry and tiny bits of fibers break off more easily and create dust. This can contribute to the dust in any house. It does in ours. Good 3M pleated filters work better, IMO, than electrostatic household ones (we've had those too.)

I have house dust allergy and learmed all this ages ago.

"I'd like more info on your whole house filter system. It doesn't seem to be doing enough. Is it a media filter? What MERV level of filter are you using now. ? Is it showing any build-up? What size is it. 4". 6" 12" thick ridgid cell. Have you changied it?"

It's a Honeywell high-efficiency, 4 inch, MERV 11. It's this one: F100F2025/U Filtration | Honeywell Home

It was just put in end of summer, so no need to change it yet. I was in the habit of changing the filters September and March on the AprilAire in the other house instead of once a year, which I'll continue to do.

"Wall-to-wall carpet can generate, catch, hold, and send out an amazing amount of house dust."

No carpet inside my home other than rugs/mats in front of entrances and the kitchen sink and stove.

I think we are finally getting some where with preparing op with what she should tell/ask contractors when they show up. To recap,dust might be coming from crawl space,walls,ceiling,windows,attic,carpet floors,dryer,ac ducts and/or ac coils. Hope I didn't miss any and would like to add a few that have been overlooked so far. Dust on the furniture could be origionating from pets bringing it in from yard,from kid's clothing after playing outdoors,shoes and clothing of someone that work's in dirty inviroment or from unwashed visitors. One thing is for certain,we've narrowed it down to alow telling contractor with certainty it's either something minor,something major or a combination of minor and major things. Keep ideas coming so no possibility is overlooked. Surly with this many heads,someone is bound to come up with the answer. In a kinder,gentler time not that long ago people always answered questions like this without the slightest hesitation. It seem's Covid in combination with recent polarization over political opinions has dulled people's analytical capabilities. As an example both OP and moi-même overlooked the possibility dust is brought in by OP after working in her garden.

ça y est!

I have one of those bulky looking HEPA filters on each floor of my home, including basement. They definitely catch quite a bit. I turn all mine on for 12hr when I goto bed each night. The amount of dust they pulled after I moved in to my newly constructed home was insane.

"I live on a dirt road" and "I also suspect leaky windows -- I can feel the drafts, but then again the problem is worse when the house is shut."

The problem is worse when the house is shut? Sorry Charles your reading skills aren't as good as you claim they are.

We can speculate all we want from a forum board... that's all it is -- speculation. There are a myriad number of ways in which this problem exists. Getting to the bottom of it is not likely to be resolved from a forum board, other than to provide clues, with vivid examples. Which only I have done. (talk is cheap, in more ways than one.)

HVAC -- all day everyday is a job that is done on location on a dirt road, gravel road, asphalt road, concrete road --- in a town or city near you. Just because you "don't live" on a dirt road doesn't necessarily make these kinds of problems disappear. HVAC design, what is it worth in a world who chooses things based on a name on the side of a box to solve problems with?

I've already provided different reasons how, what, when, why --- you may be dealing with said problem. While others simply pass it off as leaking ducts, related to stack effect. This doesn't mean leaking ducts won't contribute to said problem.

From a forum board we don't have the ability to know --- outside of guessing. Anyone can play, but that doesn't mean they should. You don't get a job as a quarterback coach, by Monday morning quarterbacking... do you?

I service the Katy, Texas area.

It's a Honeywell high-efficiency, 4 inch, MERV 11. It's this one: F100F2025/U Filtration | Honeywell Home

It was just put in end of summer, so no need to change it yet. I was in the habit of changing the filters September and March on the AprilAire in the other house instead of once a year, which I'll continue to do.

It's quite common that the cure to this problem is reportedly just putting in a new bigger filter. If one inch is good, 4 inches better.

So why didn't this 4 inch filter solve all your problems? (gimmick provided by the filter people get this filter all your problems go away. Skip your iron intake for the day... you're full.)

Design. Dust is in all air, whether you live on a dirt road or not. --- a single return --- creates "air flow" that is drawn where? -- a specific single location in your house.

The dust in that house (whether on a dirt road or not) get drawn to this single area of the home with this "vacuum" of air every time the HVAC cycles on.

So again... what happens with the air when the HVAC cycles off? air stagnates, dust is heavy and now falls where ever it is in the structure. (the vacuum this creates can? pull outside air, or just simply pull air thru walls, floors... air takes the path of least resistance. Close a door, that door acts as a damper that will increase pressure in one area -- create vacuum in others.

Does the dust accumulate everywhere or only a specific area in the home?

Does the dust accumulate everywhere or only a specific area in the home?

Pretty much everywhere but is the worst in the great room, which is over the crawl space. But other rooms are dusty, too (rest of the house is over a basement).

"a single return --- creates "air flow" that is drawn where? -- a specific single location in your house."

I don't think it's been established that the OP has only a single return grill. They noted that they have a pleated MERV 11 filter which would be installed in a filter box at the air handler.

I have air returns in every room and the hallway (single story); exception is the foyer, the two bathrooms, and the small laundry room.

I have air returns in every room and the hallway (single story); exception is the foyer, the two bathrooms, and the small laundry room.

Just so you know that is rare. Upwards of 95% of the homes I have been in, homes that I will go to do not have air returns in every room.

So this will likely make the solution much more complicated, certainly outside of the realm of what a forum board can provide. Only so much can be done from a forum board.

It may be typical in Katy, TX for HVAC systems to have a single return grill at the air handler, but HVAC systems which are properly designed with respect to air distribution will have multiple returns if they serve more than one room with a door. We, well, distribute the returns throughout the level served by the particular air handler and we always put one in each bedroom.

Additional return air grills and the additional ductwork associated with them only provides more locations where ductwork needs to be sealed, I don't think it makes a solution more complicated.

who built the home Charles? The builder grade logic in me that questions comments that are riddled with befuddlement.

That same builder will blame the HVAC guy, that the builder had a hand in hiring. (contractual obligations).

If the solution isn't so complicated, why does the problem exist? Even after installed a 4 inch media filter? A new HVAC system?

You know here where we call a spade a spade. "reality as it were."

Sometimes houzz threads stray off topic. It might be good to restate at least a portion of the OP's original post:

"I had a new furnace and a/c system installed this summer, including Honeywell whole house filter system."

That would suggest to me that the replacement contractor didn't do a complete job, but merely swapped out some equipment, thus the OP is seeking help from houzzers.

"It's quite common that the cure to this problem is reportedly just putting in a new bigger filter. If one inch is good, 4 inches better.

So why didn't this 4 inch filter solve all your problems? (gimmick provided by the filter people get this filter all your problems go away. Skip your iron intake for the day... you're full.)"

I read on the interwebs that one shouldn't use their furnace filter to clean their house, it exists to keep the inside coil clean. I use a typical MERV 8. Mine however is huge, 4x20x25. But this 4" filter can filter out more than a 1" due to the pleats.

And on each floor I have devices that are actually meant to rid the air of dust and other undesirables.

That would suggest to me that the replacement contractor didn't do a complete job, but merely swapped out some equipment, thus the OP is seeking help from houzzers.

----------------

Ironically this doesn't mean the problem didn't exist prior to the new system being installed.

I read right here (quoted below) from the OP, the problem existed before the new system. So again I ask you Charles what about the builder? You know as to prove to you and your "contractually obligated partners" --- just casting blame on the HVAC contractor? Certainly didn't do xyz, but in a land of selecive biding choosing this and that over price? Not hard to draw some conclusions to that?

Plenty of ways to read between the lines here and find someone new to blame. It starts with the builder 9 times out of 10. The house didn't build itself did it?

--------- From the OP -------------

I had a new furnace and a/c system installed this summer, including Honeywell whole house filter system. I also had the gravel floor of the crawl space under the addition covered in plastic (not encapsulated, though). And STILL the dust is ridiculous. --------End Quote------

Still? the dust is ridiculous? Meaning there was a problem before. Not hard to figure that one out. So who do we blame now for this with this new look at the info provided.

We don't know to what extent the problem existed prior to the HVAC replacement nor the extent to which it's better or worse. The problem could trace its roots to the original design and installation or poor maintenance or even damage to the system post installation. What we do know is that the replacement system isn't meeting the OP's needs. The last contractor to touch the system owns the problems. I suspect they didn't take a more comprehensive look at the system, but rather, replaced some bits and pieces. That's not a complete job.

Well the OP took the time to highlight and capitalize the word "STILL". Which of course why I framed the response as I did.

Last contractor to touch: well you can argue that all you want but if the quote didn't include duct work? If he offered some guarantee in writing that would resolve the dust issue, maybe then.

A contractor isn't going to give duct work away for free, these decisions good or bad are decided on price all day everyday.

I doubt it would stand up in court and if it did he'd likely file bankruptcy, start up under a new name. Nothing new there.

So we'll now frame this as how the builder gets away with builder designed problems --- let's blame it on the guy who last touched it?

(only solves the builder's problem... but the builder is off the hook a year or two after the house was built even though they were the last one's to build it / touch it as it were?) So the last one to touch it defense is rather weak IMHO.--example of how to read between the lines...

That being said... it would be *completely* different if HVAC contractor caused this problem directly... meaning it didn't exist before and provided you got right on it to contest it. I believe there would be some sort of time limit, just as a builder gives you after you take possession.

Oh, the problem definitely existed before this new furnace and a/c -- which STILL was meant to convey.

Oh, the problem definitely existed before this new furnace and a/c -- which STILL was meant to convey.

Thanks for chiming back in, but how you worded it... made it very clear to me. Due to the nature of dust everywhere and complexity of such problems, returns in nearly all rooms this is a job to be done in person.

The info provided thus far gives you a better understanding of how such situations occur.

I'd like to reiterate what Cavimum posted regarding rugs really contributing to dust. I moved from a home with mostly wall to wall carpet and the heat was hot water baseboard, no AC. The dust seemed to grow overnight with clumps of dust bunnies weekly. The current house is a hot air system with no carpet or rugs. I vac weekly, sometimes twice due to very light floors. I dust once and find very little on my dust wand although I do every door frame, window frame, and all the baseboard in more than 2000sf.

"We don't know to what extent the problem existed prior to the HVAC replacement nor the extent to which it's better or worse."

I've lived in Texas and realize their version of the English language is different from that in most other states. "Extent" means the degree to which the problem existed and the degree to which it continues to exist. Another, perhaps more simple way of interpreting the above statement is "how much better or how much worse is the problem after the new system was installed?" Was there any noticeable improvement? If it got worse, how much worse?

Something minor,something major or a combination of minor and major things.

I've lived in Texas and realize their version of the English language is different from that in most other states.

LOL. Then there's people in Virginia who don't read what's there to begin with. Even when the operative word is capitalized and highlighted? Before your brain surgery --- get your eyes checked Charles. ha, ha, ha.

Update: Well, it seems as though the plastic over the gravel in the crawl space helped to a pretty fair degree. The last time I dusted was two weeks ago, and there is a small amount of dust but nothing too bad -- previously the entire table in that room would be covered in a layer of dust so thick the entire table looked gray if I went two weeks between dustings; actually, that would happen closer to only one week. So two weeks with just a small amount of dust? A few hundred bucks well spent!!

That doesn't fix the zoning problem though...I'll deal with that down the road.