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.
Guardsman Coil Cleaning: The Northbrook Owner’s Guide
Guardsman coil cleaning in Northbrook typically runs $340-$580 for a full evaporator or condenser coil service, including access, chemical wash, and post-service photo documentation. We stock Guardsman-compatible coil treatments and can schedule most Northbrook homes within 48 hours, including properties near Northbrook Court and along Dundee Road where aging Carrier and Lennox systems share the same cabinet footprints. Most owners realize their coil needs attention when the upstairs never cools below 78°F despite the compressor running nonstop, or when their energy bill jumps 30% in a single July.
Which Guardsman Models This Applies To
Guardsman coils ship under several series designations, and the part you need depends on whether you’re looking at the evaporator coil inside the plenum (the sheet-metal box above your furnace) or the condenser coil in the outdoor unit. The CMQ series and CMS series are the two most common in Northbrook homes built between 1995 and 2010; the CMQ uses a 17-inch cabinet width, while the CMS runs 21 inches. Check the foil label on the right-hand side of the coil pan - it’ll read “Guardsman” followed by a six-digit code starting with CMQ or CMS.
Aftermarket equivalents exist from Aspen and ADP, but we’ve found the fin spacing on Guardsman originals (8-10 fins per inch on the CMQ, 12-14 on the CMS) doesn’t always match the aftermarket density, which changes static pressure across the coil. For Northbrook’s older two-story colonials with original ductwork, that pressure shift can mean weak airflow to the second floor. We stock both OEM Guardsman treatments and verified-match aftermarket options on our trucks, and we’ll show you the fin-count comparison before you choose.
CleanRun Air Duct Cleaning Northbrook is an independent service provider - not affiliated with Guardsman - and we carry Lennox, Trane, and Carrier coil treatments as well for mixed-brand systems common in this market.
Signs Your Guardsman Coil Cleaning Is Failing

- Ice buildup on the refrigerant lines. When the evaporator coil can’t exchange heat because of fin blockage, the refrigerant stays cold enough to freeze condensation on the suction line. In Northbrook, we see this most in late June when humidity spikes and a dirty coil finally crosses the threshold.
- Water pooling below the air handler. A clogged condensate pan or blocked drain line backs up when the coil sheds more water than the system can carry away. The camera showed a 3-inch debris build-up at the first elbow on a Northbrook Court job last summer - the pan had been slowly overflowing for two weeks before the ceiling stain appeared.
- Musty, sour smell from registers. Organic growth on the coil surface pumps into every room. Guardsman’s aluminum fin stock doesn’t corrode easily, but the steel tube sheets will, and that rust holds moisture where mold colonizes.
- Compressor short-cycling or running continuously. The system can’t reach setpoint because heat transfer is choked. We logged a 47-minute runtime on a Dundee Road home where the coil had never been cleaned in 16 years of ownership.
- Visible fin deformation or corrosion spots. Northbrook’s freeze-thaw cycles let outdoor condenser fins collect salt and road grit from nearby arterial roads. Once fins bend flat, no chemical wash restores them - the coil needs replacement evaluation.
Before
AfterReplacement Cost & What’s Included
Our installed coil cleaning service in Northbrook breaks down as follows:
| Service Item | Price Range |
|---|---|
| Evaporator coil cleaning (indoor, includes plenum access) | $340-$480 |
| Condenser coil cleaning (outdoor unit) | $280-$380 |
| Both coils, same visit | $480-$580 |
| Condensate pan/drain flush (if needed) | $85-$120 |
| Biocidal treatment post-cleaning | $65-$95 |
The range reflects access difficulty - some Northbrook basements have the furnace wedged into a closet with a 22-inch door, others have a full walk-out with room to work. Every price is written before we touch a panel, per Haven Standard Clause 1. The 365-Day Done Right Promise covers the work: if airflow readings don’t improve or the smell returns, we return and make it right - backed in writing, not subject to manager approval. Your job record includes the before-and-after photo set from inside the plenum and the coil surface.
DIY or Call Us?

There’s a safe middle ground and a hard stop. What you can do: verify your filter size and change interval (a 1-inch filter past 60 days is often the real culprit), check that the outdoor condenser has 18 inches of clear space on all sides, and listen for the compressor engaging when the thermostat calls for cooling. What you shouldn’t attempt: opening the sealed plenum to reach the evaporator coil, using pressure washers on delicate aluminum fins, or applying foaming chemicals without knowing your system’s refrigerant type. The evaporator sits downstream of the blower in a negative-pressure zone - disturb the wrong seal and you’ve got a duct leak that costs more than the cleaning would have. Tomas Reyes and our crew carry refrigerant-safe tools and the right fin combs for Guardsman density; we’ll show you the camera photo before quoting a dollar figure. The camera doesn’t negotiate - it just shows you what’s there.
FAQs
In our climate, with pollen-heavy springs and road grit from winter salt, a coil cleaning holds 18-24 months before measurable buildup returns. Homes with pets or near construction (the new development along Skokie Boulevard, for example) may need annual service. Call (224) 351-9772 and we’ll put a maintenance interval in writing based on your actual system.
No - “repair” isn’t the right frame. A coil with intact fins and no refrigerant leak is a cleaning candidate; a coil with corroded tube sheets, multiple refrigerant leaks, or fin damage exceeding 30% needs replacement. We photograph both conditions and show you the difference before any decision.
A single evaporator or condenser coil cleaning runs 90-120 minutes including setup, chemical dwell time, rinse, and post-service airflow verification. Both coils in one visit typically takes three hours. You’ll receive the timed photo record as part of the standard job documentation.
Yes - we carry Guardsman OEM fin-safe cleaner, matching fin combs for CMQ and CMS series, and the Aspen/ADP aftermarket alternatives. For Northbrook calls, we confirm your series code when you book so the technician arrives with the right spec, not a guess.
Ready to see what’s actually inside your plenum? Call (224) 351-9772 for a free, written estimate before any work begins. We’ll bring the camera first.
Written by Tomas Reyes, Owner, CleanRun Air Duct Cleaning Northbrook at CleanRun Air Duct Cleaning Northbrook, serving Northbrook and nearby areas.




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