Lots of dust in home with cathedral ceilings

I own a 2700 square ft house in Minnesota it was built in 1987 it has a cathedral ceiling and i have so much dust I started exploring the air intake vent outside and cold air return vents and the air intake outside is caked on with what looks like dust and in a upstairs bedroom my twin 3 year old daughters room I pulled the cold air return vent off and found spider webs and now I think the dust on the intake vent was spider webs also. Any help I can get I don't know if maybe the cold air return vents are placed wrong but the spider webs really creaped me out

Spider webs are kind of normal. Outside air is filthy IMO, and it's normal to have a lot of dust on the air intake of a 26-year old house. Is the dust inside your house remarkable in any way, i.e., is it like drywall, insulation, or like dust you'd see anywhere? There can be many reasons for having lots of dust; I'm afraid nobody will be able to help you much without a lot more information.

It is normal dust. I have been here for almost 2 years. It is a lot of dust when the sun starts going down and it shines through the window I can see all the dust in the air it looks like fibers but when it lands on furniture it looks just like any other dust but if I do not dust for 5 days there is a layer of dust where in my last house I rarly dusted the house but would dust once a month and in this house I have a 16x25x4 air filter in the furnace it says on the filter to check every 6 months and I change it once a month and it is black I have a 3 zone system in the basement I have transite ducts in the floor I hope this helps thanks again for any help

spider webs are a sign of air leakage. if the inside of the return has spider webs
then it is not sealed.
this leakage brings in dirty air that bypasses the filter.

"I pulled the cold air return vent off and found spider webs and now I think the dust on the intake vent was spider webs also."


so return has spider webs inside, and on the grill itself?
can you take some pics inside of r/a and of the grill?
maybe one where the grill is attached to the wall from
inside the return?

what type of insulation in the attic do you have?

Those fibers you see are likely fiberglass insulation particles from the attic being brought in due to leaks in the duct and holes/cracks in the structure. An energy audit should be your first step. www.comfortinstitute.org , www.bpi.org , www.resnet.us

I agree with the last posts regarding the returns not being sealed. Another possibility is building leakage around things like can lights, electrical boxes, exhaust fan enclosures...etc. If there is a negative pressure for some reason in the building (exhaust fans, door closure with forced air...) insulation or other stuff may be sucked into the building on a very regular basis.