Air Duct Sealing & Repair in Fort Collins, CO

Energy Waste

When supply ducts leak in unconditioned spaces (attics, crawlspaces, garages), the conditioned air your HVAC system worked to produce escapes before reaching the rooms it was meant to serve. The equipment must run longer to compensate. For a typical Fort Collins, CO home with $200/month average heating and cooling bills, fixing 25 percent duct leakage can save $50/month, over $600 per year, every year, for the life of the home.

Comfort Problems

Leaky ductwork is one of the most common causes of uneven heating and cooling. Rooms far from the air handler get less conditioned air than rooms close to it, because the air closer to the source has not yet leaked away through duct joints. The result: master bedrooms that never reach setpoint, finished basements that struggle to stay comfortable, and bonus rooms that the HVAC system cannot adequately serve.

Indoor Air Quality Compromises

When return ducts leak, they draw air from wherever they pass through, typically dirty, dusty, contaminated spaces like attics, crawlspaces, or garages. That air mixes with your conditioned air and is delivered through supply registers into your living spaces. Common contaminants pulled into supply air through duct leaks include attic insulation fibers, crawlspace moisture and mold spores, dust accumulation, carbon monoxide from attached garages, and pesticides or chemical storage products. Sealing return ducts is one of the most underappreciated IAQ improvements available.

Equipment Stress

Leaky ductwork forces HVAC equipment to operate longer to satisfy thermostat calls. Longer runtimes mean more wear on blower motors, compressors, and heat exchangers. Sealed ductwork reduces equipment runtime, extends component life, and reduces maintenance and replacement costs over time.

Pressure Imbalances

Significant duct leakage can create whole-house pressure imbalances, particularly when leaks affect supply vs return sides unequally. Negative pressure in a home can pull combustion gases backward through water heater and furnace vents (a safety hazard), pull radon from soil into the home, and increase infiltration of outdoor air at uncontrolled rates.

Disconnected Ducts

Ductwork in attics and crawlspaces sometimes pulls apart at joints over time, typically because the joints were never properly secured during original construction, or because the ductwork was disturbed by other trades (electrical, plumbing, insulation work). Fully disconnected ducts dump 100 percent of supply or return air into the unconditioned space, the worst possible failure mode.

Failed Joint Seals

Original ductwork was typically sealed with duct tape, a material that fails reliably within a few years of installation. Modern ductwork uses mastic (a permanent sealant) or UL-listed foil tape. Older homes with original tape sealing have failed joints throughout their duct systems, with each joint leaking continuously.

Damaged Flex Duct

Flexible insulated ductwork can be crushed by foot traffic in attics, torn during other work, or chewed by rodents. Damaged flex duct loses both insulation value and airtight integrity.

Improper Insulation

Ductwork passing through unconditioned spaces should be insulated to R-6 or R-8 minimum. Older or builder-grade installations often used minimal insulation or none at all, dramatically increasing energy losses even when the ducts themselves are reasonably airtight.

Undersized Returns

Many Fort Collins, CO homes have inadequate return air capacity, which forces the blower to pull harder than it should and effectively creates suction at every duct joint. Increasing return capacity often does as much for performance as sealing leaks.

Crushed or Restricted Trunk Lines

Main duct trunks in basements or crawlspaces can be damaged by other trades, storage items, or settling. Restrictions reduce overall airflow and dramatically affect performance.

Visual Inspection

We physically inspect accessible ductwork, basements, mechanical rooms, accessible attics and crawlspaces, looking for visible leaks, damage, disconnections, and insulation issues. Many problems are immediately apparent to a trained eye.

Pressure Testing

For homes with significant performance problems or where we cannot visually inspect all ductwork, we conduct duct pressure testing. We pressurize the duct system and measure leakage rates, identifying the percentage of total airflow being lost. This quantifies the problem and informs the repair strategy.

Manual Sealing (Mastic and Foil Tape)

Where ductwork is accessible, we seal joints, seams, and small leaks with mastic sealant, a thick, permanent paste applied with brushes. For larger gaps, we use mastic reinforced with fiberglass mesh. UL-181 listed foil tape is used in specific applications. Mastic sealing is durable, code-compliant, and effective when leaks are accessible.

Aeroseal Aerosol Duct Sealing

For ductwork that cannot be easily accessed, sealed in walls, ceilings, or floors, Aeroseal technology blows aerosolized sealant particles through the ductwork at slight pressure. Particles stick at leak edges and gradually seal them from the inside. Aeroseal can seal leaks too small to find manually and is effective for ductwork in finished spaces that cannot be opened up.

Repair and Replacement

When sections of ductwork are damaged beyond sealing, we replace them. New ductwork sections are sized correctly for the duct system, properly sealed during installation, and insulated where they pass through unconditioned spaces.

• Commercial-grade IAQ expertise, we install plasma air ionization and advanced filtration in Fort Collins, CO hospitals, government buildings, and corporate campuses
• Certified Carrier Factory Authorized Dealer, Carrier offers some of the best whole-house IAQ equipment on the market
• Established in 1998, over 27 years of Colorado HVAC and IAQ experience
• Trusted by Denver Health, EPA Region 8, NREL, and the Denver Public Library
• Fully licensed Colorado mechanical and plumbing contractor (P.C.0003362, M.P.00179722)
• BBB Accredited Business
• In-house, factory-trained installers, no subcontractors
• IAQ products that integrate with your existing HVAC system, no separate maintenance schedule
• Free in-home consultations and air quality assessments
• Maintenance plans that include filter changes and IAQ equipment service
• Service, repair, and parts for all major IAQ brands

How much does duct sealing cost in Fort Collins, CO?

Manual sealing of accessible ductwork typically runs $400-$1,500 depending on the extent of work and accessibility. Comprehensive duct sealing including pressure testing typically runs $1,000-$2,500. Aeroseal aerosol sealing for whole-house systems typically runs $2,000-$3,500. Specific pricing depends on the size of your ductwork, accessibility, and the extent of problems found.

How much will sealing reduce my bills?

Most Fort Collins, CO homes see 10-25 percent reduction in heating and cooling costs after comprehensive duct sealing, equivalent to several hundred dollars per year in most cases. The payback period for typical residential duct sealing is 2-5 years through energy savings alone, with continued benefits for the life of the home.

Can I seal my ducts myself with duct tape?

No. The product called "duct tape" is famously inappropriate for duct sealing, the adhesive fails within 1-3 years in HVAC operating temperatures. Proper duct sealing requires mastic, UL-181 foil tape, or aerosol sealing, and proper application techniques. Homeowner DIY attempts typically last a year or two before failing, leaving you with the same problems plus the assumption that sealing didn't work.

How long does professional duct sealing last?

Mastic sealing typically lasts the life of the ductwork, 20-30+ years. Aeroseal carries a 10-year manufacturer warranty and typically lasts much longer. UL-181 foil tape lasts 10-20+ years depending on conditions. Quality duct sealing is essentially a one-time investment for most homes.

Will sealing improve my indoor air quality?

Often dramatically. Sealing return ducts prevents your HVAC system from drawing dusty, contaminated air from attics, crawlspaces, and garages into the supply stream. Many homeowners report significant reduction in dust, allergy symptoms, and musty odors after duct sealing, even without other IAQ improvements.

How long does duct sealing take?

Most manual sealing projects complete in one day. Aeroseal installations typically take 4-6 hours. Comprehensive projects with significant repair work may take 1-2 days. We provide accurate timeline estimates with every quote.

If your home has uneven comfort, high heating or cooling bills, dusty air, or any sign that your HVAC system is working harder than it should, duct sealing is one of the highest-return improvements available. Call MSI for an inspection.