Duct Leakage Testing and Aeroseal: How Duct Cleaning Contractors Can Add Duct Sealing Services (2026)

You Are Already Inside the Customer's Ducts — The Hardest Part Is Done

Duct cleaning contractors have something no duct sealing-only company has: the ducts are already open, inspected, and documented. Adding duct leakage testing and sealing to your cleaning service can double your per-job revenue with minimal additional customer acquisition cost. The customer who pays $3,000 for duct cleaning will often pay $5,000-$7,000 for cleaning plus sealing — and the sealing addresses the root cause of dust infiltration that brings customers back for repeat cleaning.

The Duct Leakage Problem: Why It Matters to Your Customers

Commercial duct systems typically leak 15-30% of the air they carry. This leakage: wastes 10-30% of HVAC energy (conditioned air leaking into unconditioned spaces), pulls contaminants into ducts from building cavities (dust, insulation fibers, mold spores from wall cavities enter through leaks), causes comfort complaints (uneven temperatures, pressure imbalances), and makes the HVAC system work harder (fans run longer to meet setpoints, equipment wears faster). After you clean a customer's ducts, they are clean — but if the ducts leak, they will be dirty again faster. Sealing the ducts after cleaning addresses the root cause.

Duct Leakage Testing: The Diagnostic Entry Point

Duct leakage testing quantifies the problem and sells the sealing job. Methods: (1) Duct pressurization test (duct blaster): Seal all registers and grilles, pressurize the duct system with a calibrated fan, measure airflow required to maintain pressure. Leakage rate = CFM at reference pressure / total duct surface area. (2) Tracer gas testing: Introduce a tracer gas (SF6 or CO2) into the duct system and measure concentration at supply registers versus in the mechanical room. Detects leaks between supply and return plenums. (3) Thermal imaging: With the HVAC system operating and a temperature differential between duct air and surrounding space, an infrared camera can identify major leaks at duct joints, access panels, and plenum connections. Offering a duct leakage test as a $200-$500 add-on to a cleaning quote creates the diagnostic foundation for a sealing proposal.

Aeroseal: Aerosol Duct Sealing Technology

Aeroseal is the leading aerosol-based duct sealing technology. Process: (1) Block all registers and grilles with foam plugs. (2) Connect the Aeroseal machine to the duct system (typically at the air handler). (3) The machine pressurizes the duct system and injects an aerosol mist of vinyl acetate polymer sealant particles (2-20 microns). (4) As air escapes through leaks, sealant particles are carried to the leak edges, where they accumulate and bridge the gap, forming a permanent seal. (5) The computerized system tracks leakage reduction in real time. Typical results: 80-95% leakage reduction in 2-4 hours for a commercial duct system. Aeroseal is not a DIY add-on — it requires certified equipment and training. The equipment investment is $30,000-$60,000 for a complete Aeroseal commercial system. However, the per-job revenue is significant: $2,500-$8,000+ for commercial duct sealing, with sealant material cost of $300-$800 per job.

Traditional Duct Sealing Methods (No Equipment Investment)

For contractors not ready to invest in Aeroseal: (1) Mastic sealant applied to accessible duct joints, seams, and plenum connections. Effective for accessible ducts in mechanical rooms, attics, and crawlspaces. Labor-intensive. (2) Aluminum foil tape (UL 181-rated) for duct joint sealing. Combined with mastic for high-pressure ducts. (3) Access panel replacement: Many leaks originate at poorly sealed access panels from previous cleanings. Replacing, gasketing, and properly sealing every access panel you cut during cleaning is itself a meaningful sealing service. Price traditional sealing at $3-$8 per linear foot of duct sealed, depending on accessibility.

The Cleaning + Sealing Bundle: Pricing and Positioning

The pitch: "After cleaning, your ducts are clean. But if they leak, they will pull dust, insulation, and contaminants back in from the building cavities. Let's seal them while we're here — we are already set up, the ducts are open, and this is the most cost-effective time to do it." This is not a sales pitch — it is a truthful description of why cleaning without sealing addresses the symptom, not the cause.

Gaolijie robotic inspection with 1080P HD video identifies leak locations in your customer's ducts — every cleaning is a sealing opportunity waiting to be identified and quoted.