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Ductwork sealing & insulation stops air leaks and improves comfort by keeping heated and cooled air inside your home.
20-30% of conditioned air escapes through duct leaks in typical Chicago homes—especially those with unfinished basements. We find the leaks, seal them properly, and insulate where needed.
Most Chicago homeowners are paying to heat their basement ceiling and attic instead of their living space.
Air Loss:
20-30% of heated/cooled air escapes through gaps and cracks
Where Leaks Happen:
$300-$600/year wasted heating/cooling your Chicago home
Common Symptoms:
Chicago-Specific Problem:
Bungalows with unfinished basements lose massive heat through uninsulated supply ducts running through 50°F basements in winter. You're heating concrete, not your kitchen.
We don't just seal visible gaps and hope for the best. Here's Bernie's systematic approach:
Check all accessible ductwork in basement, attic, and crawlspace for obvious gaps, tears, and disconnected sections.
Cost: Included in tune-up or free with sealing quote
Run system and feel for air leaking at joints. Low-tech but effective—you can feel a 20% leak easily.
Cost: Included in inspection
Infrared imaging shows temperature differences where conditioned air escapes into unconditioned spaces. We have one.
Cost: $50 add-on (optional, helpful for hidden leaks)
Visual proof of leaks—smoke gets sucked into return leaks or blown away from supply leaks. Great for showing homeowners the problem.
Cost: Included when needed
Pressurize entire house, measure total air leakage. Helps quantify duct leakage vs building envelope leaks. Most useful for energy audits.
Cost: $200 (not always necessary for basic duct sealing)
Not all duct sealing is equal. Here's what works and what doesn't.
Mastic Sealant
Professional-grade paste brushed on joints. Dries flexible, moves with ducts, lasts 20+ years. This is the gold standard.
DIY-friendly: Available at Lowe's for ~$40
Foil Tape
Metal-backed adhesive tape for rigid ductwork connections. Lasts 15-20 years. NOT the same as duct tape.
Aeroseal (Automated)
Pressurized polymer blown through system, seals from inside. Gets inaccessible leaks. Expensive but effective.
Cost: $1,500-$2,500 whole home
Duct Tape
Despite the name, cloth duct tape fails in 1-3 years on HVAC systems. Heat cycles dry out the adhesive. We see it peeling off constantly.
Lifespan: 1-3 years (terrible ROI)
Spray Foam (Overused)
Spray foam can seal gaps but restricts airflow if overdone. Some contractors spray first, ask questions later. We use it sparingly for specific situations.
"Sealing" Without Inspection
If we can't see or access the leak, we can't seal it properly. Aeroseal solves this problem, but manual sealing requires visual access.
Bernie's take: If you have an unfinished basement and can see all your ducts, buy mastic at Lowe's and DIY it. You'll save $400-600. We'll inspect your work during your next tune-up and tell you if you missed anything. Attic ducts and inaccessible runs? Call us—that requires experience and safety equipment.
Sealing stops air from escaping. Insulation stops heat from transferring through duct walls. Both matter, but insulation is only needed in specific situations.
Unfinished Basements
Supply ducts running through 50°F basements lose 20-30% of heat through metal duct walls even if sealed. R-6 minimum insulation required by Chicago code.
Attic Ductwork
140°F attics in summer, 10°F in winter. Uninsulated ducts work against your AC/furnace. R-8 insulation minimum, higher is better.
Crawlspace Ducts
Vented crawlspaces act like outdoor spaces. All ductwork needs R-6 wrap minimum.
Garage Runs
Ducts passing through attached garages (unconditioned space) must be insulated.
Labor + Materials:
$3-6 per linear foot
Installed (R-6 or R-8 wrap)
Typical home: 50-100 linear feet of basement ducts
Total: $400-800 installed
When insulation ISN'T needed: Ducts running through conditioned space (finished basement, interior walls) don't need insulation. You're already paying to heat/cool that space. Insulation only matters in UNconditioned areas.
Transparent pricing. No surprises. Here's what different levels of service actually cost.
Accessible basement ductwork (20-30 connections)
Best for: Unfinished basements with accessible ductwork
Basement + attic ductwork sealing
Best for: Homes with both basement and attic ductwork
50-100 linear feet of duct insulation
Best for: Already-sealed ducts in unconditioned spaces
Complete sealing + insulation whole home
Most popular: Addresses both air leakage AND heat transfer
What It Is:
Pressurized polymer sealant blown through entire duct system. Seals from inside, reaches inaccessible leaks behind walls and in ceilings.
Process:
Cost:
$1,500-2,500
Whole home (typically reduces leakage by 60-90%)
When It Makes Sense:
Average Investment
$1,200
(seal + insulate)
Annual Savings
$300-500
(energy bills)
Payback Period
2.5-4 years
(then pure savings)
Lifespan: 20+ years for mastic sealing and insulation. After payback, you're saving $300-500/year for the next 15+ years. Total ROI: $4,500-7,500 on a $1,200 investment.
Different Chicago housing types have different duct problems. Here's what we see most often:
The Problem: Supply ducts running through 50°F basements in winter. You're heating your basement ceiling instead of your living room. Most common duct issue we see.
The Fix: Seal all joints with mastic + R-6 insulation wrap on all supply ducts. Cost: $800-1,200 for typical bungalow. Savings: $400-600/year.
ROI: 1.5-2 years (best payback of any home type)
The Problem: Leaky ducts hidden behind finished ceilings. Can't access without demolition.
The Fix: Aeroseal is only realistic option for hidden ducts. Seals from inside without demo. Cost: $1,500-2,500.
Alternative: Live with it until you remodel, then seal during drywall removal
The Problem: Upper unit too hot in summer, lower unit too cold in winter. Usually caused by duct leakage between floors and poor return air balance.
The Fix: Seal floor penetrations + balance dampers + possible return air upgrades. Cost varies widely ($500-2,000 depending on accessibility).
Often need both duct sealing AND zoning controls for two-flats
The Problem: Rare in Chicago but some ranch-style homes have attic-mounted furnaces. Ductwork in unconditioned attic fights against 140°F summer heat.
The Fix: R-8 insulation minimum on all ducts + seal all connections. Some homes benefit from moving equipment to basement (expensive but best solution).
Attic duct insulation: $800-1,500 depending on attic access
We're honest: Sometimes sealing ducts won't solve your comfort or efficiency problems. Here's when you need more than sealing:
Symptom: Room gets little to no airflow even though ductwork is sealed.
Cause: Flex duct crushed under insulation, rigid duct collapsed, or physical damage from rodents/construction.
Fix: Duct replacement for damaged sections. Can't seal a crushed duct back to life.
Cost: $500-1,500 per section depending on accessibility
Symptom: System struggles to heat/cool, runs constantly, loud airflow noise at registers.
Cause: Original system was 2-ton, homeowner upgraded to 4-ton, but ducts stayed the same size. Or home addition added rooms without upgrading ductwork.
Fix: Duct redesign and replacement. Sealing won't help if your ducts are physically too small for the equipment.
Cost: $2,000-5,000 for major duct upgrades (we'll tell you if this is the issue)
Symptom: Rooms get hot/cold, door gaps whistle, pressure imbalance when doors close.
Cause: Room has supply register but no return air path. Air can't circulate properly. Common in bedroom additions and finished basements.
Fix: Add return air grilles, install transfer grilles above doors, or undercut doors. Sometimes requires new ductwork runs.
Cost: $200-800 per room for return air solutions
Bernie's Promise: We'll tell you if duct sealing won't solve your problem. We'd rather be honest and recommend duct replacement or redesign than take your money for sealing that won't fix the root issue. If your ducts need replacement, we'll explain why and quote it properly.
Unlike most HVAC companies, we'll actually tell you when you can save money doing it yourself.
Savings: $400-600 in labor. We'll inspect your work during your next tune-up for free.
Bernie's approach: Start with DIY if you're handy and have accessible ducts. Seal what you can reach. Then call us for a $89 tune-up—we'll bring a thermal camera and show you what you missed. If you got 80% of it, great. If there are attic ducts or inaccessible leaks causing problems, we'll quote the professional fix. You save money, we earn your trust.
Basic sealing of accessible basement ducts runs $400-$800 (20-30 connections). Comprehensive whole-home sealing (basement + attic) costs $800-$1,500. Full service including insulation runs $1,200-$2,500. Aeroseal automated sealing is $1,500-$2,500. Average payback is 2.5-4 years through energy savings.
If you have an unfinished basement and can see all your ducts, yes—buy $40 of mastic at Lowe's and brush it on yourself. Save the money. Professional service is needed for attic ducts (access/safety), inaccessible runs behind walls, Aeroseal system, and proper insulation installation. We'll tell you during a tune-up if you missed anything.
Properly applied mastic sealant lasts 20+ years. Foil tape on rigid ductwork also lasts 15-20 years. Aeroseal sealing is permanent (as long as ducts aren't damaged). Duct tape fails in 1-3 years and is NOT recommended for HVAC ductwork despite the name.
Typical Chicago homes lose 20-30% of heated/cooled air through duct leaks. Sealing and insulating ducts saves $300-$500 per year on average. Biggest savings come from homes with uninsulated basement or attic ductwork. You'll also notice better comfort—fewer hot/cold spots between floors.
Yes. A new high-efficiency furnace still wastes energy if your ducts leak. In fact, the problem gets worse—higher efficiency = hotter supply air = bigger temperature difference when it leaks. We recommend sealing ducts BEFORE installing a new furnace for maximum ROI.
Schedule a duct inspection. We'll show you where you're losing money, quote the fix honestly, and tell you if DIY makes sense for your situation.
Inspection included with comprehensive sealing service. Thermal camera available for $50 add-on.