Mid-fall is when our phones get busy. The furnace has been running every day for a few weeks, the windows are shut until April, and people start noticing things: dust on the TV stand a day after dusting, a smell when the heat kicks on, a back bedroom that never warms up. The first question on almost every call is the same — what's this going to cost me? — so here's a straight answer, with three typical jobs broken down line by line.
A quick note on the examples: the three homes below are representative jobs, built from the kinds of houses and findings we see every October and November across Chicagoland. They're not one specific customer's invoice, but the scope and the pricing are exactly how we'd quote them.
How we price duct cleaning (and why it's by furnace)
Every furnace in a house runs its own duct system — its own blower, its own trunk lines, its own set of supply and return runs. That makes the furnace count the most honest way to size a job. It's also why we don't price per vent: per-vent pricing is where a "cheap" quote turns into a big one once someone starts counting registers in your living room.
Each package covers unlimited supply and return vents, every main trunk line, and the furnace blower cleanout. For context, the Better Business Bureau puts a realistic whole-system price range at roughly $450 to $1,000, depending on system size, access, and how dirty it is — so our one- and two-furnace prices sit squarely in the normal band, not the bargain bin and not the premium tier.
The part that surprises people is what happens before we quote. We don't give a final number over the phone, because we haven't seen your system. Instead, every job starts with a $175 home air inspection: we open registers, look into the supply and return trunk lines (with a camera where it helps), check the furnace blower, filter, and coil. You get a written list of what needs cleaning and a locked-in price. If you go ahead, the $175 is credited toward the work — so a one-furnace job is $550 total, not $725. If the ducts don't need cleaning, we tell you that, and you've paid $175 for a straight answer instead of a sales pitch.
Case 1: One-furnace ranch where only the supply side needed cleaning
A classic call from Park Ridge: a homeowner in a mid-century ranch got a "$99 whole-house duct cleaning" flyer in the mailbox and wanted to know whether it was worth it or whether they even needed cleaning. They'd lived in the house eight years, changed the filter every few months, and had no pets. The complaint was mild — dusty supply registers in the bedrooms and a faint "hot dust" smell for a day or two after the furnace first came on.
What the inspection showed:
- Return side in good shape. Regular filter changes had done their job. The return trunk and the big hallway return had light dust, nothing that restricts airflow.
- Supply side dirty. The supply registers looked like the one below, and a look inside showed a visible layer along the bottom of the supply trunk and branch runs — years of fine dust that got past the filter and settled downstream.
- Blower acceptable. Some dust on the wheel, but not the felt-like coating that causes airflow and smell problems.
A supply register typical of a supply-only job — drag the handle to compare. When the returns are clean, this is where the dust ends up.
What it cost: We cleaned the supply side only — every supply register, the branch runs, and the supply trunk — and left the returns alone because they didn't need it. That brought the final price in under the $550 one-furnace rate, with the $175 inspection credited inside that number. The homeowner's takeaway was the useful part: keep changing the filter on schedule and the returns will stay clean, which is what kept this job small.
Case 2: Two-furnace colonial with a burning smell every cycle
This is the October call we get the most. A two-story home with one furnace in the basement for the first floor and a second unit in the attic for the bedrooms. The heat came on for the season, and instead of a normal burning dust smell that fades in an hour, it came back every time either furnace cycled — for four days. Upstairs, the kids' rooms were two or three degrees colder than the thermostat said they should be.
What the inspection showed:
- Both blower wheels coated. The attic unit was the worse of the two — attic systems pull in more dust and get serviced less because nobody wants to climb up there.
- Heavy buildup in the main trunks. Inside, we found the kind of dust you see below, clinging to all four walls of the supply trunk, not just the floor of it.
- Returns dirty too. The filters were the thin fiberglass kind and hadn't been changed since spring, so dust had been getting past them on both systems.
A main supply trunk before and after whole-system cleaning. Buildup on the walls and ceiling of the duct, not just the floor, means dust has been getting past the filter for a long time.
What it cost: Whole-system cleaning on both furnaces — every supply and return, all trunk lines, and both blower cleanouts — for $950, with the $175 inspection credited inside it. There's no separate line for the attic unit being harder to reach, and no per-vent count, even though this house had well over thirty registers. The smell was gone on the next heating cycle, and moving to a better pleated filter was the one change we recommended to keep it from coming back.
Case 3: Kitchen remodel dust — plus a dryer vent we didn't expect
A kitchen remodel wrapped up in September. The drywall crew sanded for two days with the HVAC system running, and by the time the furnace came on in October the homeowner was replacing a filter every two weeks and still seeing a fine gray film on every surface. This is exactly the situation post-renovation duct cleaning exists for: drywall dust is much finer than household dust, and it goes straight through ordinary filters and settles everywhere downstream.
Construction dust looks different from household dust: finer, lighter in color, and spread evenly along the whole run instead of piled in corners.
Since the inspection can include the dryer vent, we checked the laundry room too, because the homeowner mentioned towels were taking two cycles to dry. The dryer vent ran about twenty feet through a finished basement ceiling to an exterior wall, and the flexible transition hose behind the dryer looked like this:
That's not a comfort problem, it's a fire problem: the NFPA lists failure to clean as the leading cause of home dryer fires, and fall is when dryers start running more loads of heavy clothes and bedding. Since we were already on site, we added dryer vent cleaning to the same visit.
What it cost: Whole-system cleaning for the one furnace at $550 — post-renovation jobs use the same furnace-count pricing, no "construction surcharge" — plus the dryer vent, which we quoted at the inspection after measuring the run and checking the exterior hood. One inspection covered both, and the $175 was credited once.
The three jobs side by side
| Job | What we found | What we cleaned | Final price |
|---|---|---|---|
| 1 furnace, ranch | Clean returns, dusty supply side | Supply registers, branches, supply trunk | Under $550 |
| 2 furnaces, colonial | Coated blowers, heavy trunk buildup, dirty returns | Whole system ×2, both blowers | $950 |
| 1 furnace, post-remodel | Drywall dust throughout, lint-packed dryer vent | Whole system + dryer vent | $550 + dryer vent |
In all three, the $175 inspection is already included in the final price, not added on top of it.
What the $99 flyer doesn't tell you
We get asked about the $99 offers every fall, so here's our side of it, plainly. A real whole-system cleaning takes a crew several hours: HEPA negative-air equipment connected to the system, agitation tools run through every branch, the blower cleaned out. Nobody can do that for $99 and stay in business. What the $99 usually buys is a quick pass on a handful of vents — then the extras start: per-vent charges past the first ten, a separate price for the "main line," a blower fee, and a "sanitizer" or mold treatment the technician says you need once they're inside.
The industry's own trade group warns about exactly this; NADCA's homeowner guides on spotting duct cleaning scams are worth five minutes before you book anyone. Whoever you hire, ask these five questions first:
- Is the price all-in, in writing, before you start? Not "starting at," not per vent.
- Does it include the furnace blower? Cleaning the ducts and leaving a dirty blower recontaminates everything on the first cycle.
- Are both supply and return sides covered — and if one doesn't need it, will you tell me?
- What equipment keeps the dust from coming back into the house? You want to hear "negative air" and "HEPA."
- Will you show me what's inside my ducts, before and after? If they won't, you have no way to know what was done.
For what it's worth, those are the same five things every whole-system air duct cleaning in Chicago we do is built around: one price by furnace count, the blower always included, HEPA negative-air equipment, and a walk-through of what's actually inside your ducts.
When duct cleaning isn't worth the money
Not every call ends with a cleaning, and it shouldn't. The EPA's position on when to have air ducts cleaned is a useful filter: it's warranted when there's visible mold growth, pests, or enough dust and debris to clog the ducts or blow out of the registers — not as routine maintenance on a system that's clean. In practice, we tell people to skip it when:
- The home is newer, the filter has been changed on schedule, and the inspection shows only a light film.
- The ducts were professionally cleaned in the last few years and nothing has changed since (no remodel, no new pets, no water event).
- The real complaint is stuffiness, humidity, or allergy symptoms rather than visible dust — those often have causes outside the ductwork.
For that last group, indoor air quality testing is usually a better first step than cleaning. Measuring particulates, humidity, and VOCs tells you what's actually in the air, and sometimes the fix is a better filter or a humidity problem, not the ducts at all.
Why mid-fall is a smart time to book
By late October the furnace is running several times an hour, every hour, and it will keep doing that until spring. Whatever is in the blower and the supply trunk gets pushed through every room on every cycle, with the windows shut. Cleaning now means you start the longest stretch of indoor heating with a clean system instead of finishing it with one — and it's done before Thanksgiving guests arrive and before the December rush, when inspection slots fill up fastest.
Frequently asked questions
How much does air duct cleaning cost in Chicago?
With us, whole-system cleaning is $550 for one furnace, $950 for two, and $1,250 for three, including unlimited supply and return vents, all main trunk lines, and the furnace blower. Every job starts with a $175 inspection credited toward the work, and because many homes only need the supply side cleaned, the final price is often lower than the headline number.
Why is air duct cleaning priced by furnace instead of by vent?
Each furnace serves its own duct system with its own blower and trunk lines, so the furnace count is the most honest measure of the work. Per-vent pricing is where surprise charges come from — the advertised price covers a few vents and every other register gets added on site.
Is a $99 whole-house air duct cleaning deal legitimate?
Rarely. A proper whole-system cleaning takes a crew several hours with negative-air equipment, which can't be done for $99. Those offers typically cover a few vents or a quick vacuum pass, then add per-vent charges, blower cleaning, or chemical treatments once the technician is inside. Get a written, all-in price before any work starts.
Does the $175 inspection add to the price of duct cleaning?
No. If you go ahead, the $175 is credited toward the work, so a one-furnace whole-system cleaning is $550 in total, not $725. If the inspection shows you don't need cleaning, you pay only the $175 and keep the written findings.
Is fall a good time to get air ducts cleaned?
Yes. Once the furnace is running daily, whatever is in the blower and supply ducts is pushed through the house every cycle, and the windows stay closed for months. Cleaning in October or November removes that load before the longest stretch of heating — and before holiday guests arrive.
What is the difference between supply-only and whole-system duct cleaning?
Supply ducts carry heated or cooled air from the furnace to the rooms; returns carry it back through the filter. When the filter has been changed regularly, the returns are often fine and only the supply side needs cleaning, which lowers the price. Whole-system cleaning covers both sides plus the blower and is needed when dust has gotten past the filter or after a renovation.
