Short answer: Installing a new AC system without first assessing your ductwork is one of the most expensive mistakes a Las Vegas homeowner can make. The average pre-2010 home in this valley loses 20-35% of conditioned air through duct leaks, crushed flex runs, and degraded insulation — meaning your brand-new 20 SEER system performs like a 13-15 SEER system from the moment it is turned on. A professional duct assessment takes 1-2 hours, costs $150-$300 (often credited toward repairs), and reveals exactly what is stealing your comfort and your money. The right time to fix ductwork is BEFORE or DURING your AC replacement — not after you have spent $10,000 and are still wondering why the upstairs bedroom is 82 degrees.
Ready for a duct assessment before your AC replacement? Call (702) 567-0707 or book online.
Key Takeaways
- A new AC connected to old, leaky ductwork wastes 20-35% of its cooling capacity. That $10,000-$15,000 investment is delivering $6,500-$12,000 worth of performance from day one. The most expensive system on the market cannot compensate for a broken delivery system.
- Las Vegas attics amplify every duct problem. With attic temperatures reaching 150-170 degrees F, even minor duct leaks and insulation gaps become catastrophic. Cool air that leaves your AC at 55 degrees can arrive at your registers at 68-75 degrees — barely cooler than the room it is supposed to cool.
- A professional duct assessment costs $150-$300 and takes 1-2 hours. It includes a visual inspection, duct leakage test, static pressure measurement, register temperature checks, and insulation evaluation. Many companies credit the cost toward repair work.
- Duct sealing costs $1,500-$3,000 and typically pays for itself in 2-4 years through reduced energy bills. Over the 15-year life of your AC system, fixing 30% duct leakage can save $10,000 or more in wasted energy.
- The best time to fix ductwork is when you replace your AC. Bundling saves $500-$1,500 in labor overlap, and your contractor can properly size the new system based on improved duct performance — which may mean you need a smaller, less expensive unit.
- If your HVAC contractor says "your ducts are fine" without testing, that is a red flag. No one can assess ductwork from the living room. A quality contractor inspects ducts before finalizing any equipment recommendation.
The Dirty Secret of HVAC Replacement
I am the co-CEO and CFO of The Cooling Company. I have sat with thousands of Las Vegas families during the AC replacement process — and the pattern I see repeated breaks my heart every time.
A homeowner's AC fails in June. They are desperate. They call two or three companies. Every contractor walks in, looks at the outdoor unit, checks the model number, and starts talking about equipment: tonnage, SEER ratings, brands, financing. The homeowner picks one, writes a check for $10,000 to $15,000, and the crew installs a beautiful new system.
Six weeks later, the homeowner calls back. The upstairs is still five degrees warmer than the downstairs. The system runs for hours. The energy bill barely changed. They are frustrated. They feel cheated. They ask: "Did you install a defective unit?"
No. The unit is perfect. The problem is the same one that existed before the replacement: the ductwork. And nobody talked about it.
Here is what most HVAC companies will not tell you, because it complicates the sale: in Las Vegas, the average home built before 2010 loses 20-35% of its conditioned air through duct leaks and poor insulation. That means your brand-new 20 SEER system — the one you researched for weeks, compared across three contractors, and financed for 60 months — is actually performing like a 13-15 SEER system. You paid for a luxury sedan. You are driving a base model. And you will drive that base model for the next 15 to 20 years because nobody bothered to check the tires before they swapped the engine.
I have seen too many families spend $10,000 on a beautiful new system and then call us a year later because their upstairs is still hot. The answer is almost always ductwork.
This is the conversation most HVAC companies skip. We do not. Because selling you a new AC without assessing your ductwork is not serving you — it is just moving inventory.
What Ductwork Actually Does and Why It Matters So Much
Your AC system has two jobs: create cold air and deliver it to every room in your house. The outdoor unit and evaporator coil handle the first job. Your ductwork handles the second. If the delivery system is broken, it does not matter how efficient the source is.
Think about it this way. A brand-new water heater connected to leaky pipes still delivers lukewarm water. A high-performance engine with a cracked radiator hose still overheats. The source can be world-class, but if the path between the source and the destination is compromised, performance collapses.
Your ductwork is that path. It consists of a network of insulated tubes — typically flexible duct in Las Vegas homes — running from the air handler in your garage or attic through the attic space and down into the walls to supply registers in every room. Return ducts pull air back to the system to be recooled and recirculated. The entire loop must be sealed, insulated, properly sized, and unobstructed for your AC to deliver what you paid for.
In Las Vegas specifically, this delivery system operates in one of the harshest environments imaginable. Your ducts run through attics that reach 150-170 degrees F on a typical summer day. That is not a metaphor. I have measured attic temperatures above 170 degrees in North Las Vegas and Henderson homes during July. Any weakness in your duct system — a loose connection, compressed insulation, a kinked flex run — is amplified by the extreme temperature difference between the air inside the duct and the air outside it.
In a mild climate, mediocre ductwork might cost you 10% efficiency. In Las Vegas, the same ductwork costs you 30% or more. The stakes are higher here than almost anywhere else in the country.
The 5 Ways Las Vegas Ductwork Fails
Every duct system I inspect tells a story. After two decades in this business, I can walk into an attic and identify problems within minutes because the same five failures show up in home after home across this valley. Here is what we find — and why each one costs you money.
1. Duct Leaks: The Biggest Culprit
Duct leaks are the single most common and most expensive ductwork problem in Las Vegas homes. Over time, the joints where flex duct connects to metal boots, plenums, and takeoffs loosen and separate. The strap clamps that secure these connections lose tension. The inner liner of flex duct tears at stress points. And every one of these failures sends cooled air directly into your attic.
You are literally air conditioning your attic. That 55-degree air your system worked hard to produce? It is dumping into a 160-degree space where it does absolutely nothing for your comfort — except make your system run longer trying to compensate for the loss.
Typical leakage rates in Las Vegas homes built before 2010: 20-35%. Some homes I have tested exceeded 40%. That means for every 100 cubic feet of cool air your system produces, only 60-80 cubic feet actually reaches your living space. The rest vanishes into the attic.
The worst part: you cannot see duct leaks from inside your house. Air still comes out of your registers. The system still runs. Everything appears normal — except your bills are high, your comfort is poor, and your system is working twice as hard as it should be. For a deeper look at how to spot leaks, see our guide on leaking air ducts.
2. Inadequate Insulation
Even sealed ductwork loses performance if the insulation around it is insufficient. Flex duct comes wrapped in insulation — typically fiberglass with an outer vapor barrier. The R-value of that insulation determines how much heat transfers from the attic into the cool air traveling through the duct.
Here is the problem: most Las Vegas homes built in the 1990s and 2000s were installed with R-4.2 insulated flex duct. That was code-minimum at the time. But R-4.2 insulation in a 160-degree attic is grossly inadequate. The cool air traveling through that duct gains 8-12 degrees before it ever reaches the register.
You set your thermostat to 76 degrees. Your system produces 55-degree air at the coil. By the time that air travels 20-30 feet through R-4 insulated duct in your attic, it arrives at the bedroom register at 63-67 degrees instead of 55 degrees. That is a massive loss of cooling capacity.
In longer duct runs — the ones serving upstairs rooms, back bedrooms, or rooms at the far end of the house — the heat gain is even worse. The air might arrive at 68-72 degrees. You wonder why that bedroom is always warm. Now you know: the air reaching it was never cold enough to cool it effectively.
Modern code requires R-8 insulation for attic ductwork. Homes built to current standards have significantly better duct performance. But if your home is 15 to 25 years old, your duct insulation is almost certainly underperforming — and it has only gotten worse as the fiberglass has compressed and degraded over years of extreme heat cycles.
3. Crushed or Kinked Flex Duct
Flexible duct is exactly what it sounds like — a soft, bendable tube. That flexibility makes it easy to install. It also makes it easy to damage.
Every time someone enters your attic — HVAC technicians, insulation installers, cable and internet technicians, pest control — they are walking near or over your ductwork. One misplaced step crushes a duct run. One heavy tool bag dropped on a duct kinks it flat. And once flex duct is crushed, the airflow to that room drops by 50-80%.
Every time I go into a Las Vegas attic, I find at least one kinked or partially collapsed run. It is that common. The homeowner has no idea. They just know that bedroom is always warm, or that bathroom fan does not work as well as it used to, or that one register barely produces any air while the others blow strong.
A crushed duct also creates turbulence and noise. If you hear a whistling or rushing sound from a particular register, a restriction upstream is a likely cause.
4. Undersized Ductwork
When you upgrade to a larger or more powerful AC system, your ductwork has to be able to handle the increased airflow. If the original ducts were designed for a 3-ton system and you install a 4-ton or 5-ton system, the ducts become a bottleneck.
The analogy I use with homeowners: trying to drink a milkshake through a coffee stirrer. The milkshake machine works fine. The cup is full. But the delivery path is too narrow, so you get frustrated and the machine works harder than it needs to.
Undersized ducts create high static pressure in the system. High static pressure reduces airflow, which reduces the amount of heat the evaporator coil can absorb, which can cause the coil to freeze. A frozen coil means no cooling at all — and potential damage to the compressor, which is the most expensive single component in your AC system.
I have seen homeowners spend $12,000 on a premium 5-ton system, connect it to 6-inch duct runs designed for a 3-ton, and then wonder why the system keeps freezing up. The system is trying to push 2,000 CFM through ducts sized for 1,200 CFM. Something has to give, and it is usually the equipment.
This is exactly why a duct assessment should happen BEFORE the new system is ordered. If your ducts are undersized, your contractor needs to know that before they recommend equipment tonnage. Fix the ducts, and you might need a smaller — and less expensive — AC system than you thought.
5. Disconnected Runs
This is the worst-case scenario, and it is more common than you would expect. A flex duct connection to a boot or plenum fails completely, and the duct separates. Now 100% of the cooled air intended for that room is dumping directly into the attic.
The room served by that duct gets zero cooling. Not reduced cooling — zero. The homeowner closes vents in other rooms trying to redirect air. They set the thermostat lower. They buy portable fans. Nothing works, because the air never makes it past the attic.
I have walked into attics and found disconnected ducts that had been separated for years. The homeowner thought they just had a "hot room." They did not — they had a completely disconnected duct run that was hemorrhaging cooled air into the hottest part of their home.
A disconnected duct also acts as a massive hole in the system, pulling superheated attic air into the return side when the system runs. This means every room suffers, not just the disconnected one.
What a Professional Duct Assessment Includes
A proper duct assessment is not a technician glancing at your vents and saying "looks fine." It is a systematic evaluation of your entire duct system using specific diagnostic tools and measurements. Here is what should happen during a professional assessment.
Visual Inspection
The technician enters the attic (or crawlspace, if applicable) and physically inspects every visible duct run. They are looking for disconnected sections, crushed or kinked flex duct, damaged insulation, improper support, and visible gaps at connections. This takes time. A thorough visual inspection in a typical Las Vegas home requires 30-45 minutes in an attic that is often 140-160 degrees. It is demanding work, and it is the only way to find problems that no instrument can detect from inside the house.
Duct Leakage Test (Duct Blaster)
This is the most important diagnostic tool in a duct assessment. A duct blaster test pressurizes your entire duct system and measures total leakage in CFM25 (cubic feet per minute at 25 Pascals of pressure). This gives a precise, objective measurement of how much air your duct system is losing.
| Duct Leakage Rate (CFM25) | Rating | What It Means |
|---|---|---|
| Under 6% of total airflow | Excellent | Minimal air loss. System operating near peak efficiency. |
| 6-12% | Acceptable | Minor leakage. Sealing would improve performance but is not urgent. |
| 12-20% | Needs improvement | Noticeable comfort and efficiency loss. Sealing recommended, especially with a new system. |
| Over 20% | Significant performance loss | Major comfort problems. Substantial energy waste. Sealing or replacement strongly recommended before installing new equipment. |
Most Las Vegas homes I test fall in the 18-35% range. That is a lot of conditioned air going nowhere useful.
Static Pressure Measurement
Static pressure tells you whether your ductwork is properly sized for the airflow your system needs. Think of it as measuring the "blood pressure" of your duct system. High static pressure means the ducts are too small, too restrictive, or too convoluted for the volume of air the system is trying to move. Low static pressure can mean the ducts are so leaky that they cannot maintain pressure at all.
A properly sized duct system for a residential AC should operate between 0.3 and 0.5 inches of water column (IWC). Above 0.5 IWC, the system is working harder than it should, reducing efficiency and shortening equipment life. Above 0.7 IWC, you likely have a serious sizing or restriction problem.
Temperature Measurement at Registers
The technician measures the temperature of the air at the supply plenum (where it leaves the air handler) and at each supply register throughout the house. The difference between these two measurements reveals heat gain in each duct run. A well-insulated, sealed duct run should show no more than 2-4 degrees of heat gain. Runs showing 8-15 degrees of gain have insulation or sealing problems — or both.
Insulation Assessment
The technician checks the R-value and condition of the insulation wrapped around your flex duct. R-4 duct insulation in a Las Vegas attic is insufficient. R-6 is the old minimum. R-8 is the current standard. Beyond the R-value, insulation condition matters: fiberglass that has compressed, gotten wet, separated from the duct, or been torn during previous service calls no longer provides its rated protection.
Documentation and Recommendations
A professional assessment ends with a written report documenting findings — leakage test results, static pressure readings, register temperatures, insulation condition — and specific recommendations. This report should explain what needs to be fixed, the priority of each repair, estimated costs, and expected performance improvement.
How Long It Takes and What It Costs
A thorough duct assessment for a typical Las Vegas home takes 1-2 hours. Cost ranges from $150 to $300, and many reputable companies credit this fee toward repair or replacement work if you proceed. It is one of the highest-value services you can buy, because the information it provides can save you thousands in avoided waste and guide smarter decisions about your AC replacement.
The Cost of Ignoring Ductwork
I am a numbers person. I am the CFO of this company for a reason. So let me walk you through the financial reality of ignoring ductwork during an AC replacement.
The Annual Waste
The average Las Vegas homeowner spends $2,400 to $3,600 per year on cooling. If your ductwork is leaking 30% of the conditioned air, 30% of that spending is literally disappearing into your attic. That is $720 to $1,080 per year — gone.
But the waste compounds. When your system loses 30% of its cooling capacity through the ducts, it runs longer to compensate. Longer run times mean higher electricity consumption beyond the 30% direct loss. Factor in the extended runtime penalty and total waste climbs to 35-40% — closer to $840 to $1,440 per year.
The Lifetime Cost
The average AC system lasts 15-18 years in Las Vegas. Using conservative numbers — $900 per year wasted over 15 years — you are looking at $13,500 in wasted energy over the life of the system. And that assumes energy prices do not increase, which they will.
But the financial damage does not stop at energy bills.
The Hidden Costs
Shortened equipment lifespan. A system running 35-40% harder than it needs to wears out faster. Instead of 15-18 years, you get 10-13 years. That means replacing a $10,000-$15,000 system 3-5 years sooner than necessary.
Higher repair frequency. Overworked systems break down more often. Compressor failures, frozen coils, blower motor burnout — all are more common in systems fighting against leaky ductwork. A single compressor replacement costs $1,500-$3,000.
Uneven comfort. Rooms that never reach setpoint. Second floors that are always 5-8 degrees warmer. Family members arguing over the thermostat. Portable AC units purchased in desperation. These are not line items on a spreadsheet, but they are real costs to your quality of life.
The Math on Fixing It
| Scenario | Annual Energy Cost | 15-Year Energy Cost | Duct Fix Cost | 15-Year Net Savings |
|---|---|---|---|---|
| Do nothing (30% duct leakage) | $3,200 | $48,000 | $0 | Baseline |
| Duct sealing ($2,000) | $2,300 | $34,500 | $2,000 | $11,500 |
| Partial replacement ($4,000) | $2,100 | $31,500 | $4,000 | $12,500 |
| Full replacement ($8,000) | $1,900 | $28,500 | $8,000 | $11,500 |
Every option pays for itself. Duct sealing is the highest ROI — a $2,000 investment returning $11,500 over 15 years. Full replacement costs more upfront but delivers the greatest annual savings and also extends equipment life, adds comfort improvements, and eliminates future duct maintenance issues.
The question is not whether you can afford to fix your ductwork. The question is whether you can afford not to. For more on how these numbers play out with different efficiency levels, read our guide on real efficiency savings in Las Vegas.
Duct Repair vs. Replacement: When Each Makes Sense
Not every duct system needs to be ripped out and replaced. Some need targeted repairs. Some need comprehensive sealing. And some genuinely need a full replacement. Here is how to know which category your home falls into.
Duct Sealing (Aeroseal or Manual)
Duct sealing is appropriate when the ductwork itself is structurally sound — the flex duct is intact, properly supported, and correctly routed — but the connections are leaking. This is the most common scenario in homes built in the 2000s and 2010s.
Manual sealing involves a technician physically accessing each connection point and sealing it with mastic sealant and metal-backed tape. It is labor-intensive but effective for accessible ductwork.
Aeroseal is a newer technology. The system temporarily seals all registers, pressurizes the duct system, and blows aerosolized sealant particles through the ducts. The particles collect at leak points and build up to seal them from the inside — including leaks that are impossible to reach manually. Aeroseal can reduce duct leakage by 80-90% and is particularly effective for ductwork buried in walls, between floors, or in tight attic spaces where manual access is impossible.
Cost: $1,500-$3,000 depending on home size and leak severity.
Best for: Homes built after 2000 with intact duct material, moderate leakage (12-25%), and accessible ductwork. Also ideal when the ductwork is properly sized and routed but simply has age-related connection failures.
Partial Duct Replacement
Sometimes the problem is concentrated. Three of your eight duct runs are in good shape, but the five that run through the hottest part of the attic are deteriorating. Or the trunk line from the plenum is undersized, but the branch runs are fine. Partial replacement addresses the worst sections while preserving what still works.
Common scenarios include replacing attic runs while keeping wall-cavity ducts intact, upsizing the main trunk line while retaining properly sized branch runs, or replacing specific damaged sections that have been crushed, disconnected, or repeatedly patched.
Cost: $2,500-$5,000 depending on the scope of replacement.
Best for: Homes with specific problem areas rather than system-wide failure. Homes where some duct runs were already replaced or repaired. Situations where budget constraints prevent full replacement but critical improvements are needed.
Full Duct Replacement
Full duct replacement means removing the entire existing duct system and installing new ductwork from the plenum to every register. This is the most comprehensive solution and makes sense when the existing ductwork is beyond repair.
When full replacement is the right call:
- Ductwork is more than 25 years old and showing widespread deterioration
- Original ductboard (fiberglass board duct) is installed — ductboard degrades, grows mold, and cannot be effectively sealed
- Ductwork is severely undersized for the new system being installed
- Previous repairs and patches have created a system that is more tape than duct
- The home is getting a complete HVAC overhaul and the homeowner wants maximum performance for the next 20 years
Cost: $5,000-$12,000 depending on home size, number of runs, attic accessibility, and insulation specification.
Best for: Pre-1995 homes, homes with ductboard, homes upgrading to significantly larger or higher-efficiency systems, and homeowners who want a clean start. If you are upgrading an older home, our older homes guide covers additional considerations.
Comparison Summary
| Repair Type | When It Is Appropriate | Typical Cost | Expected Improvement |
|---|---|---|---|
| Duct sealing (manual or Aeroseal) | Sound ductwork with leaky connections | $1,500-$3,000 | 15-25% efficiency gain, more even temperatures |
| Partial replacement | Specific damaged sections, mixed condition | $2,500-$5,000 | 20-30% efficiency gain in affected zones |
| Full replacement | Widespread deterioration, undersized, or ductboard | $5,000-$12,000 | 25-40% efficiency gain, complete comfort transformation |
The Best Time to Fix Ductwork
The answer is straightforward: fix your ductwork when you are replacing your AC system.
This is not just a convenience recommendation — it is a financial and performance optimization. Here is why.
Labor overlap saves money. When your AC is being replaced, a crew is already in your attic disconnecting old equipment, running new refrigerant lines, and connecting the new system. Adding duct repairs or replacement to the same project eliminates duplicate labor costs. Bundling ductwork with an AC replacement typically saves $500-$1,500 compared to doing them as separate projects.
System sizing becomes more accurate. If your contractor assesses and fixes your ductwork BEFORE finalizing the new AC system recommendation, they can size the equipment based on improved duct performance. A home that needed a 5-ton system with 30% duct leakage might only need a 4-ton system once the ducts are sealed. That downsize saves $1,000-$2,000 on equipment cost and delivers better performance — because a properly sized system runs longer, steadier cycles that distribute air more evenly and control humidity better.
Everything gets tested together. When the new AC and repaired ductwork are commissioned simultaneously, the technician can verify that the complete system — equipment, ducts, and controls — works as an integrated unit. Static pressure, airflow balance, register temperatures, and refrigerant charge can all be checked against the design specifications for the combined system. Issues are caught immediately, not six months later when you realize the master bedroom is still warm.
One disruption instead of two. Your attic gets accessed once. Your system gets shut down once. You deal with one project, one timeline, one invoice.
The most common regret I hear from homeowners: "I wish I had done the ductwork at the same time as the AC." They save $500 during the installation by skipping the duct assessment, and then spend $3,000 six months later when the new system does not perform as expected. Do it right the first time. For a broader view of how to approach a total system upgrade, see our complete comfort upgrade guide.
What to Ask Your HVAC Company About Ductwork
If you are getting quotes for a new AC system, these questions will tell you whether the contractor actually cares about your long-term results or is just trying to sell equipment.
"Will you do a duct leakage test before sizing my new system?" A quality contractor performs diagnostic testing to understand the full picture before making recommendations. If they have not tested your ducts, they are guessing about a factor that affects 20-35% of system performance.
"What insulation level will you install on new or replacement ductwork?" The answer should be R-8 at minimum for Las Vegas attic installations. If they say R-4 or R-6, they are installing to an outdated standard that will cost you money every month.
"Can I see the static pressure readings after installation?" Post-installation static pressure verification proves the duct system is properly matched to the new equipment. If a contractor cannot or will not provide this, they are not commissioning the system — they are just turning it on and leaving.
"Are you going to check existing connections to the new equipment?" When a new air handler is connected to existing ductwork, every connection point between old and new must be properly sealed and secured. This is where lazy installations create the leaks that haunt you for years.
"What does your quote include for ductwork?" Some contractors include basic duct inspection in their standard replacement quote. Others charge extra. Either is acceptable, but you need to know before comparing bids.
If a contractor says "your ducts are fine" without going into the attic, without running a single test, without even looking at the ductwork — that is not an assessment. That is a sales tactic designed to keep the quote simple and the close fast. Walk away.
For a complete list of questions to vet any HVAC contractor, read our 17 questions to ask before buying a new HVAC system.
How Duct Problems Affect Two-Story Homes
If you have a two-story Las Vegas home, ductwork problems are amplified. The duct runs serving second-floor rooms are the longest, passing through the hottest part of the attic. They experience the greatest heat gain, the most potential for leaks, and the longest path for air to lose pressure and temperature.
This is why the second floor of so many Las Vegas homes is 5-8 degrees warmer than the first floor — even with the AC running constantly. The duct runs to those upstairs rooms might be losing 30-40% of their cooling capacity through a combination of leaks and heat gain. The air that finally arrives at the second-floor register is barely cooler than the room itself.
A duct assessment is especially critical for two-story homes. In many cases, sealing and insulating the second-floor duct runs resolves the temperature imbalance that homeowners have been fighting for years. It is often a more effective solution than zoning systems or supplemental equipment — because the root cause is not too little cooling capacity but too little of that capacity reaching the rooms that need it.
For a detailed exploration of two-story home cooling challenges, see our guide on two-story home cooling solutions.
Frequently Asked Questions
How do I know if my ductwork is leaking?
Common signs include uneven room temperatures (some rooms 3-5 degrees warmer than others), high energy bills despite a newer AC system, excessive dust in the home, weak airflow from certain registers, and the system running long cycles without reaching the thermostat setpoint. You can do a simple check by holding a tissue near register grilles to compare airflow strength, or by feeling around exposed duct connections in the attic for escaping air. However, the only way to measure total duct leakage accurately is a professional duct blaster test, which pressurizes the system and quantifies the exact leakage rate. If you suspect leaks, start with our leaking air ducts guide for DIY diagnosis steps, and then schedule a professional assessment for precise measurement.
How much does duct sealing cost in Las Vegas?
Professional duct sealing in Las Vegas typically costs $1,500 to $3,000 depending on home size, accessibility, and the severity of leakage. Manual sealing (mastic and tape applied at each connection) is on the lower end of that range. Aeroseal duct sealing, which uses aerosolized sealant blown through the system to seal leaks from the inside, is on the higher end but reaches leaks that manual sealing cannot access. Both methods pay for themselves in 2-4 years through reduced energy bills. When bundled with an AC replacement, the cost is often lower because the crew is already working in the attic.
Should I replace ductwork when I replace my AC?
It depends on the condition of your existing ductwork, which is exactly what a duct assessment determines. If your ductwork is less than 15 years old, structurally sound, and testing below 12% leakage, sealing is likely sufficient. If the ductwork is original from the 1990s, has ductboard construction, shows widespread deterioration, or is undersized for the new system, replacement makes more sense. The key is to make this decision BEFORE the new system is installed — not after. Bundling duct work with AC replacement saves $500-$1,500 in labor and ensures the new system is sized correctly for your actual duct performance.
How long does ductwork last in Las Vegas?
Flex duct in Las Vegas attics typically lasts 15-25 years before significant degradation occurs. The extreme heat accelerates the breakdown of insulation, inner liners, and connection materials. Ductboard (rigid fiberglass board duct) has a similar lifespan but is more prone to mold growth and interior deterioration. Metal ductwork lasts longest — 25-30+ years — but is less common in residential Las Vegas construction. The actual lifespan depends heavily on installation quality, insulation grade, and whether the attic has been accessed frequently (which increases the chance of physical damage). If your home was built before 2000, your ductwork is approaching or past the point where a professional assessment should be considered mandatory before any equipment investment.
Can I seal my own ductwork?
You can address some visible issues — reattaching a loose strap clamp, applying foil-backed HVAC tape to an accessible connection, or repositioning a kinked flex run. Do NOT use standard cloth "duct tape" for duct sealing; despite the name, it fails quickly in attic heat. Use UL-listed foil tape or mastic sealant for any DIY repairs. However, most duct leaks occur at connections that are buried under insulation, located in tight spaces, or impossible to see without removing duct sections. A professional with proper equipment can identify and seal leaks you will never find on your own. Aeroseal technology can seal leaks throughout the entire system — including inside walls and between floors — without manual access to each leak point. For anything beyond basic visible repairs, professional duct repair is the reliable path.
What is Aeroseal duct sealing?
Aeroseal is a patented duct sealing technology that works from the inside out. The process involves temporarily blocking all registers, pressurizing the duct system, and injecting aerosolized sealant particles into the ducts. These particles are carried by air to leak points, where they accumulate and form a permanent seal. The system monitors leakage in real time, so the technician can verify exactly how much leakage was eliminated. Aeroseal can seal leaks up to 5/8 inch in diameter and typically reduces total duct leakage by 80-90%. It is particularly valuable for ductwork that runs through inaccessible spaces — inside walls, between floors, or in tight attic areas where manual sealing is impossible. The sealant is UL-tested, meets fire safety standards, and carries a 10-year warranty.
How much can I save by fixing leaky ductwork?
A Las Vegas home with 30% duct leakage and annual cooling costs of $2,400-$3,600 is wasting roughly $720-$1,440 per year in lost conditioned air and extended system runtime. Reducing that leakage to under 10% through professional sealing saves $500-$1,000 annually. Over the 15-year life of an AC system, that totals $7,500-$15,000 in energy savings — far exceeding the $1,500-$3,000 cost of the sealing work. Additional savings come from reduced system strain (fewer repairs, longer equipment life) and improved comfort (potentially eliminating the need for supplemental cooling equipment like portable AC units or fans that many homeowners buy out of frustration).
What is the difference between a duct assessment and a duct cleaning?
A duct assessment is a diagnostic service that evaluates the physical condition of your ductwork — measuring leakage, static pressure, heat gain, insulation condition, and airflow distribution. It tells you what is wrong and what needs to be fixed. Duct cleaning is a maintenance service that removes dust, debris, and contaminants from inside the ducts. Cleaning does not fix leaks, repair insulation, or improve airflow. Both services have value, but they serve completely different purposes. If you are preparing for an AC replacement, a duct assessment is the priority — it directly affects equipment selection, sizing, and long-term performance. Cleaning can follow once the ductwork is in good structural condition.
Will fixing my ductwork reduce hot spots in my house?
In most cases, yes. Hot spots — rooms that are consistently warmer than the rest of the house — are almost always caused by ductwork problems: a leaky connection reducing airflow to that room, inadequate insulation causing heat gain in the duct run serving that room, a crushed or kinked section restricting flow, or an undersized duct run that cannot deliver enough air. A duct assessment identifies which specific problem is causing each hot spot, and targeted repairs address the root cause rather than the symptom. I have seen duct sealing resolve temperature differences of 5-8 degrees between rooms — turning a frustrating, unevenly cooled home into a consistent, comfortable one.
Protect Your Investment
A new AC system is one of the largest investments you will make in your home. In Las Vegas, it is also one of the most important — your family depends on that system for safety and comfort during months of extreme heat.
Do not let that investment perform at 65-70% because nobody checked the delivery system. A duct assessment before your AC replacement is the difference between buying a system that delivers its full rated performance and buying one that fights its own ductwork every day for 15 years.
The assessment takes two hours. It costs less than a single month of wasted energy. And it gives you the information you need to make a decision that protects your comfort and your wallet for the life of the system.
If you are considering a new AC system — or if you already have one that is not performing the way you expected — call The Cooling Company at (702) 567-0707 or request a free estimate. We will start with the ductwork, because that is where the truth is. Comfort Club members receive priority scheduling and discounted diagnostic fees.
This is the conversation most HVAC companies skip. We believe it is the most important one.