Whole-system duct and dryer vent check with before-and-after photos - you see exactly what came out of your vents
That "$99 whole-house special" is a bait ad - the real number appears once they are in your hallway, or the "clean" is a shop-vac at the register. We photograph the inside of your ducts before and after instead.
Rotobrush Vent Sanitizing: The Denver Owner’s Guide
Rotobrush vent sanitizing in Denver typically runs $340-$580 for a whole-system treatment, installed, and we stock the full Rotobrush-compatible chemical line on our trucks. Most Capitol Hill and Wash Park jobs we book are completed same-day because the solution is mixed on-site to match the contamination level the camera finds. Here is what the camera found. Here is what it costs to fix it. You decide.
Owners usually figure out something’s off when the Rotobrush agitation runs but the vent still smells like the previous owner’s cooking, or when a post-cleaning mold test comes back positive despite visible debris removal. The sanitizing step is what kills what brushing leaves behind.
Which Rotobrush Models This Applies To
Rotobrush vent sanitizing attaches at the solution-injection point on the Rotobrush Beast series (model years 2018-present), the classic Rotobrush BrushBeast, and the portable Rotobrush aiR+ models. The Beast and BrushBeast share a 3/8-inch quick-connect port for the sanitizing wand; the aiR+ uses a smaller 1/4-inch fitting that requires a reducer we keep in stock. Check the label plate on the motor housing: “Beast” units show a 14-amp draw, while aiR+ units draw 7.5 amps. That amperage figure is the fastest way to confirm which fitting set you need.
OEM Rotobrush sanitizing solution ships as a concentrated quaternary ammonium compound, EPA-registered for HVAC systems. We also stock a commercial-grade equivalent from Guardsman that matches the 800-1,200 ppm application range and carries the same EPA registration for porous duct surfaces. The OEM bottle runs higher per gallon; the Guardsman equivalent performs identically in our documented photo records and costs less. We quote both in writing before mixing anything.
One compatibility gotcha: pre-2018 BrushBeast units had a brass quick-connect that corrodes in Denver’s low-humidity winter static. If your fitting leaks at the wand joint, the brass has likely crystallized. We carry the stainless retrofit kit on every truck.
Signs Your Rotobrush Vent Sanitizing Is Failing

- Persistent musty odor after agitation. The brushes dislodged debris but the sanitizing agent never reached the full duct run, usually because the solution was diluted below effective ppm or the contact time was under 10 minutes. We meter the concentration and clock the dwell time on every job.
- Visible microbial growth at register edges despite recent cleaning. The Rotobrush scrubbed the main trunk but the sanitizing mist didn’t carry through to the terminal ductwork. This happens in Denver’s older Baker and Berkeley homes where galvanized duct runs have internal corrosion that traps spores.
- Solution foams at the wand but doesn’t atomize. The venturi nozzle is clogged with dried chemical from a previous job. The orifice is 0.4 mm and requires a specific cleaning pin; forcing it with wire destroys the spray pattern permanently.
- Technician reports “sanitizing applied” but no chemical odor during or after. The injection pump failed or the solution tank was empty. We photograph the tank level and the pump operating before we start, and again after.
- Allergic symptoms return within 30 days of service. The sanitizing agent killed surface biologics but didn’t penetrate the biofilm layer. In Denver’s altitude, lower boiling points can cause premature evaporation if the technician rushes the contact time.
Before
AfterReplacement Cost & What’s Included
| Service Component | Denver Price Range |
|---|---|
| Whole-system vent sanitizing (Rotobrush-compatible, up to 12 duct runs) | $340-$480 |
| Heavy contamination / visible mold (extended dwell, higher concentration) | $480-$580 |
| Stainless quick-connect retrofit (pre-2018 brass replacement) | $65-$85 parts + labor |
| Additional sanitizing pass (customer-requested or post-remediation) | $120-$180 |
The range depends on three factors we document before quoting: linear feet of ductwork, contamination type (dust load versus active microbial growth), and accessibility (crawl space trunks in Park Hill Victorians take longer than basement utilities in Stapleton rebuilds). Every quote is written and signed under Haven Standard Clause 1 before we open the first register. The 365-Day Done Right Promise covers the sanitizing application; if odor or visible growth returns, we re-treat at no charge.
DIY or Call Us?

What you can safely check yourself: confirm your Rotobrush model from the motor plate, inspect the quick-connect fitting for green corrosion or cracking, and verify the solution tank has liquid (not sludge from a prior season). What goes wrong fast: mixing quaternary ammonium at the wrong concentration strips galvanized duct lining, and over-application leaves a residue that becomes a new dust adhesive. The EPA registration specifies exact ppm for a reason.
We don’t sell the chemical to homeowners. The liability is real, and the documentation matters more than the product. Call (720) 799-2292 and we’ll put the written price next to any competitor’s quote under our Free Second Opinion.
FAQs
In Denver’s dry climate, a properly applied treatment typically remains effective for 12-18 months, though homes with shedding pets or recent construction may need it sooner. The low humidity here actually extends chemical stability compared to Gulf Coast markets, but dust loading from Front Range wind events accelerates recontamination. Call (720) 799-2292 for an exact quote - estimates are free.
The wand and hose assembly can often be rebuilt if the failure is isolated to the quick-connect or a cracked wand tube; the injection pump and venturi nozzle are replaceable sub-assemblies. We diagnose on-site and quote the repair versus full replacement in writing before proceeding. Call (720) 799-2292 for an exact quote - estimates are free.
A standard Rotobrush vent sanitizing treatment takes 90-150 minutes for a single-family system up to 12 duct runs, including the documented photo record before and after each run. Heavy contamination or crawl space access adds 30-60 minutes. Call (720) 799-2292 for an exact quote - estimates are free.
We stock the full Guardsman-compatible chemical line, stainless quick-connect retrofits, and replacement wands on every truck; OEM Rotobrush solution is available by next-day order if specifically requested. We also carry parts for Lennox, Trane, and Carrier systems. CleanRun Air Duct Cleaning Denver is an independent service provider, not affiliated with Rotobrush. Call (720) 799-2292 for an exact quote - estimates are free.
Written by Tomas Reyes, Owner, CleanRun Air Duct Cleaning Denver at CleanRun Air Duct Cleaning Denver, serving Denver and nearby areas.




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