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.
Before
After
Before
After
Before
AfterGuardsman Vent Sanitizing: The Alexandria Owner’s Guide
Guardsman vent sanitizing systems installed in Alexandria homes typically run $340-$580 for a complete service including replacement of the UV-C lamp or photocatalytic oxidation (PCO) cell, full duct-run inspection, and documented before-and-after photography. We stock Guardsman-compatible lamps and cells for same-day replacement on most residential units. Most Alexandria owners discover the system has failed when they notice the indicator light is dark or catch a musty return-air smell that wasn’t there last season.
Which Guardsman Models This Applies To
Guardsman produces two residential vent-sanitizing lines relevant to the Alexandria market: the UV-C Series (GS-UV14, GS-UV18, GS-UV24) and the PCO Series (GS-PCO16, GS-PCO22). The model number is stamped on a metal tag at the lamp housing, visible once you remove the access panel at the plenum - the main distribution box where your ductwork connects to the air handler.
The UV-C lamps are length-specific: 14-inch, 18-inch, or 24-inch, and using the wrong length will either fail to seat in the mounting clips or leave dead-zone gaps where air passes untreated. The PCO cells are width-matched to your system’s airflow rating, not interchangeable across tonnage. We carry both OEM Guardsman lamps and quality aftermarket equivalents from Abatement Technologies that meet the same 253.7 nanometer UV-C output spec. For PCO cells, we stock OEM only - the catalyst coating thickness varies too much between aftermarket brands to guarantee the hydroxyl radical production rate Guardsman designed for.
One compatibility gotcha we see in Alexandria’s 1980s-2000s split-levels: some builders installed Guardsman housings but used generic lamps from a bulk HVAC supplier. The housing fits, but the electrical connector pin spacing differs by 2 millimeters. We verify pin configuration before pulling anything from the truck.
Signs Your Guardsman Vent Sanitizing Is Failing
- Dark or flickering indicator light. The UV-C lamp has a rated lifespan of 9,000 operating hours, roughly one year of continuous use. When the ballast struggles to maintain arc voltage, the lamp flickers before failing entirely - a sign the ballast may also need replacement, not just the lamp.
- Musty or sour smell from registers when the blower kicks on. A working UV-C system suppresses microbial growth on the evaporator coil and in the drain pan. When sanitizing stops, the coil becomes a breeding surface for mold and bacteria that the airflow carries straight to your rooms.
- Visible dust accumulation on the lamp sleeve. The quartz sleeve protecting the UV-C lamp should stay clear. Heavy dust coating indicates either the pre-filter is missing or the lamp has been non-functional long enough for normal particulate to settle undisturbed.
- PCO cell rattling in its track. The titanium-dioxide-coated mesh in PCO units can corrode at the frame welds after 3-4 years of humidity cycling. Alexandria’s Potomac-adjacent summers push that timeline shorter in homes without whole-house dehumidification.
- Increased allergy symptoms after HVAC runs. This is the symptom owners report last, after ruling out pollen seasons and pet dander. A non-functional sanitizing system means the ductwork is circulating untreated air through a dark, moist environment - exactly what dust mites and mold spores need.
BeforeAfterReplacement Cost & What’s Included
| Service Component | Price Range (Alexandria) |
|---|---|
| UV-C lamp replacement (OEM Guardsman) | $180-$260 |
| UV-C lamp replacement (aftermarket, Abatement Technologies) | $140-$200 |
| PCO cell replacement (OEM only) | $220-$340 |
| Ballast replacement (if needed) | $90-$150 |
| Full system service with documented photo record | $340-$580 |
What drives the range: accessibility of the plenum (some Alexandria crawl spaces in the Rosemont neighborhood require us to work around century-old joists), whether the quartz sleeve needs cleaning or replacement, and if the ballast shows voltage drop under load. Every job starts with a written price under Haven Standard Clause 1 - no exceptions. The 365-Day Done Right Promise covers the work in writing, and your job record includes before-and-after photos of every duct run, the lamp housing, and the coil condition.
DIY or Call Us?
What you can safely check yourself: confirm the lamp indicator status, verify the HVAC breaker is on, and inspect the pre-filter for clogging. Do not remove the access panel while the system is powered - UV-C lamps operate at high voltage and can cause serious electrical burns or arc flash. The quartz sleeve is also fragile; a cracked sleeve exposed to the lamp’s ozone production creates a respiratory hazard.
Where DIY goes wrong: homeowners who swap lamps without checking ballast output often burn out the replacement within weeks. Others install the wrong pin-configuration lamp and damage the socket. We test ballast voltage, verify airflow across the lamp axis (critical for UV-C effectiveness - the lamp must face the airstream directly), and photograph the coil condition so you see why the lamp failed in context. The duct doesn’t lie - we just show you what’s in it.
For a written price before any work starts, call (240) 318-7712. Estimates are free, and we stock Guardsman-compatible parts for same-day replacement in Alexandria.
FAQs
UV-C lamps last roughly 9,000 hours of operation, or about 12 months if your fan runs continuously. In Alexandria’s humid summers, we recommend annual replacement regardless of hour count - the mercury vapor degrades faster under thermal cycling. Call (240) 318-7712 to schedule before your current lamp expires.
No. The titanium-dioxide catalyst is a thin coating bonded to the mesh substrate. Any cleaning abrasive enough to remove contamination also strips the catalyst. Once the cell shows reduced odor control or visible frame corrosion, replacement is the only effective option. We verify catalyst integrity with a black-light inspection before recommending replacement.
Most replacements take 45 to 90 minutes, including ballast testing, sleeve cleaning or replacement, and photo documentation. Tight plenum locations in older Alexandria homes add time. We give you a written time estimate with the price before starting.
Yes. We carry UV-C lamps in all three lengths and PCO cells for both residential sizes, plus Abatement Technologies equivalents where appropriate. If your model is a rare commercial variant, we can source it within 24 hours. Call (240) 318-7712 to confirm your specific model before we dispatch.
CleanRun Air Duct Cleaning Alexandria is an independent service provider, not affiliated with Guardsman. We also stock parts for Lennox, Trane, and Carrier sanitizing systems.
Written by Tomas Reyes, Owner & Lead Technician, CleanRun Air Duct Cleaning Alexandria at CleanRun Air Duct Cleaning Alexandria, serving Alexandria and nearby areas.