> By: The Cooling Company
Key Takeaways
- Seal visible duct leaks and add insulation to exposed trunks to cut energy loss.
- Inspect attic and crawlspace ducts yearly and after renovations or pest visits.
- Prioritize plenum and air-handler connections, then handle returns and trunk insulation.
- For Las Vegas homeowners call The Cooling Company at 17029308411 for a duct audit and sealing.
Duct leaks, poor insulation, and restricted airflow quietly raise energy bills and lower comfort. Fix visible seams, insulate exposed attic runs, and test for hidden leakage to find the biggest savings. Start with the air handler and main trunks, then plan targeted repairs or selective replacement for worst-case sections. (ASHRAE Technical Resources)
Why does ductwork matter for my energy bills?
Ducts carry the heated or cooled air that keeps rooms comfortable. When ducts leak, the conditioned air goes into unconditioned spaces instead of rooms. That wasted air still costs energy to produce and shows up on your utility bill.
Leaky ducts also cause uneven comfort and added wear on equipment. Poor airflow can make some rooms too hot or cold and force the system to run longer. For many homes, sealing and insulating ducts is one of the fastest ways to lower energy use.
What components make up a duct system?
A duct system includes the supply and return trunks, branch runs, plenums, and registers. The air handler connects to a plenum that feeds the supply trunk. Returns collect room air back to the handler. Dampers, boots, and flexible connectors help route and balance flow.
Insulation and sealants are part of the system too. Insulation keeps conditioned air at set temperature, and mastic or rated foil tape seals seams. Each part matters for energy and comfort, so inspect them all regularly.
How does an air handler affect duct losses?
The air handler is the source of pressure for the whole network. If the plenum or handler collar is loose, a large share of conditioned air can leak right at the source. That loss often costs more than leaks at distant boots or seams. (ASHRAE Technical Resources)
Fan speed and filters change system pressure and can hide or reveal some leaks. A clogged filter reduces flow, which may lower leakage but also reduces comfort. Keep the handler sealed and maintain filters to protect efficiency.
Where do ducts most commonly leak?
Common leak sites include plenum seams, boot-to-duct joints, and flex-duct collars. These points move with temperature changes and can lose sealant. Small gaps at many joints add up to big losses across a house.
Ducts in unconditioned spaces leak the most energy. Attics and crawlspaces expose ducts to heat, pests, and accidental damage. Routine checks in these spaces catch many easy repairs and reduce seasonal energy loss.
How much energy can leaks waste?
Leaky ducts can waste a large share of heating or cooling energy in a home. Losses of ten to thirty percent are common in older or poorly sealed systems. When ducts sit in hot attics, the energy penalty goes up because supply air gets heated before reaching rooms.
A targeted sealing and insulation effort usually returns big savings. Fix the big leaks first, then seal the smaller joint leaks. Measured results after sealing help confirm actual savings.
Which parts fail first?
Plenum seams and collars at the air handler often fail first because they see the most movement and pressure. Flex-duct connections at register boots also wear out from bending and foot traffic in attics. Poor initial fastening or tape use speeds the failure.
Inspect these high-risk spots during each service visit and after attic work. Replacing worn collars and resealing seams prevents small failures from growing into major energy loss.
How can homeowners inspect ducts themselves?
Homeowners can find many problems with simple visual and hands-on checks. Start in attics, crawlspaces, and near the air handler. Look for crushed or sagging runs, loose connections, and missing insulation on exposed trunks.
Run the system fan and feel around seams for leaks. A tissue or thin ribbon held near a seam will move if air is leaking. Mark problem areas and decide which you can fix yourself and which need a pro.
How do I check for visible leaks?
Turn the fan to on and hold a tissue near seams, boots, and collars to find escaping air. Use a flashlight to look for daylight through seams in attics or crawlspaces, which signals gaps. Also check screws and fasteners for loose hardware at boots.
Document visible leaks in photos and notes so you can prioritize repairs. Simple repairs like mastic and foil tape at these spots often give immediate, noticeable improvements in comfort. (ASHRAE Technical Resources)
What tools reveal hidden leakage?
A smoke pencil, incense, or a small smoke stick shows subtle airflow at joints when the fan runs. Infrared thermometers map temperature differences along duct runs and help spot missing insulation. Professionals use a duct blaster to measure total leakage.
Thermal imaging also reveals heat gain or loss quickly in attics. If bills stay high after basic fixes, plan for professional testing to find hidden, high-impact leaks.
Can you test ducts without special tools?
Yes, simple tests help find clear problems without special gear. Use the tissue method, check for dusty streaks along seams, and watch how doors react when the system runs. These hacks point to pressure or flow problems.
Simple checks do not replace a measured leakage test. Use home methods to triage and fix obvious spots. For large or persistent problems, hire a pro with test equipment.
Which duct issues cost homeowners most?
Large leaks at the plenum, long uninsulated trunk runs in attics, and disconnected returns cause the most lost energy. Wrong-sized trunks that force the system to run inefficiently also add to bills. These faults often have the fastest payback when fixed.
Many small leaks across many joints can equal a single large leak. Prioritize repairs that stop the most loss first. That approach gives quick bill relief and improves comfort in the rooms you use most.
How do connection leaks form?
Connection leaks form from poor initial sealing, thermal movement, and mechanical wear. Tape adhesive can fail, and gaskets compress over years. Vibration from the fan can open seams that were tight at installation.
Pest damage and attic work also break seals. Reseal collars and seams with proper HVAC mastic or UL-rated foil tape to stop leaks for the long term.
Why do undersized ducts reduce comfort?
Undersized ducts restrict airflow and create high static pressure in the system. That reduced flow prevents rooms from getting the planned volume of conditioned air. As a result, the system runs longer but still fails to meet set temperatures.
High pressure can also strain the blower and shorten equipment life. Proper sizing matters for both efficiency and longevity, and correcting size faults may require selective replacement.
Repair ducts or replace the system?
Decide based on duct layout, age, and the severity of damage. Repair is cost effective when leaks and insulation issues are local and the layout and sizing are otherwise correct. Full replacement fits when ducts are corroded, badly undersized, or poorly routed across the whole house. (ASHRAE Technical Resources)
An energy audit or duct pressure test helps make the call. Many homes do best with a mix of sealing, insulation, and targeted replacement of the worst runs. Budget plans help spread larger work over time.
How much does sealing typically cost?
Sealing costs vary by home size and access. For many single-family homes, professional sealing ranges from several hundred to a few thousand dollars depending on severity. The job often includes access, mastic application, and testing before and after.
DIY sealing is cheaper but gives mixed results. Hiring a pro yields verified numbers and tends to use longer-lasting materials. Many homeowners recover costs within a few years through lower energy bills.
When is partial replacement smart?
Partial replacement makes sense when only a few runs are damaged or badly sized. Focus on major trunks and long attic runs. Replacing those sections can restore balance and airflow without the cost of full system rebuild.
Use professional sizing for the new segments so you do not create new pressure issues. Targeted work often delivers most of the comfort and efficiency gains at a lower cost.
What ROI can sealing and insulation deliver?
Return on investment depends on climate, duct location, and energy prices. Typical savings range from ten to thirty percent on heating and cooling bills when leakage is significant. Attic ducts often yield the fastest payback because they lose the most energy.
Combine sealing with correct insulation and thermostat tuning for the best result. Measured savings after professional sealing give confidence in the investment.
How should you prioritize duct repairs?
Start with high-impact fixes: plenum seams, air-handler connections, and main trunk leaks. These sites handle most of the air and often yield the biggest energy savings when sealed. Fix any disconnected returns next to restore circulation.
After the main fixes, add insulation to exposed trunks and repair crushed flex runs. Balance urgent repairs with planned replacements. Keep a log of repairs and follow-up measurements to check progress.
What sealing methods work best?
Mastic paste applied with a brush gives the longest-lasting seal on seams and collars. Foil-backed mesh tape is useful for some repairs, but choose UL-181-rated products for HVAC use. Aerosol sealing works well for many small hidden leaks in hard-to-reach systems.
Match the method to the problem. Use mastic for structural seams and aerosol for broad leakage where access is limited. Good contractors explain trade-offs and show test results. (ASHRAE Technical Resources)
Is foil tape acceptable for long-term sealing?
Foil tape is acceptable when it is UL-181-rated and applied correctly to clean surfaces. Many common cloth or cheap tapes fail quickly. Use rated foil tape for insulated ducts and pair it with mastic in high-stress spots.
Avoid standard duct tape; it degrades and loosens. Proper materials and prep lead to seals that last for years.
When should you use mastic instead of tape?
Use mastic where joints move or surfaces are irregular. Its thick paste fills gaps and resists cracking from thermal cycles. Mastic bonds well to metal and flex duct collars and creates a durable air barrier.
Apply a generous bead over seams, smooth it, and allow it to cure before adding insulation. That practice ensures a reliable long-term seal.
How often should ducts be inspected?
Inspect ducts every one to three years in most homes, and more often if ducts are in attics or crawlspaces. Homes with pets, recent renovations, or unexplained high bills benefit from annual checks. Frequent inspection catches small issues before they grow.
Pair duct checks with seasonal HVAC service for convenience. An hvac technician can spot early leaks and recommend the right fixes for the money.
What questions should you ask contractors?
Ask how they test leakage, what materials they use, and whether they provide before-and-after numbers. Request warranty details and references for similar jobs. Also ask if they use UL-rated products and follow local code. If you're exploring hvac careers, look for companies that invest in training and certifications.
Good contractors explain trade-offs clearly and show photos and test numbers. Avoid vague bids that do not include testing or clear scope.
Ready to schedule a duct audit?
Las Vegas area homeowners can book a duct audit and sealing with The Cooling Company by calling 17029308411. The team serves Las Vegas, Henderson, and North Las Vegas and offers duct blaster testing, aerosol sealing, and mastic repairs. Request documented before-and-after leakage numbers and a written plan.
If you live outside the area, ask any contractor for duct blaster testing and NATE-certified technicians. These credentials help ensure trained staff and reliable results when you compare bids.
Call The Cooling Company at 17029308411 to schedule a duct inspection and start saving on your energy bills today. Our crews in Las Vegas, Henderson, and North Las Vegas provide testing, sealing, and insulation work with clear documentation and a focus on lasting results.
About The Cooling Company
The Cooling Company has been serving the Las Vegas valley with professional HVAC services for over a decade. Our team of licensed, NATE-certified technicians specializes in air conditioning repair, heating system maintenance, and complete HVAC installations. We're committed to providing honest, reliable service with upfront pricing and a 100% satisfaction guarantee on all work performed.
- Phone: (702) 930-8411
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Service Areas
We proudly serve homeowners and businesses throughout the Las Vegas metropolitan area, including Las Vegas, Henderson, and North Las Vegas. Our service technicians are available for same-day appointments in most areas, with emergency service available 24/7 for urgent HVAC issues.