What You’ll Learn
How can you improve home comfort and reduce energy waste?
By addressing leaks and insulating ducts, you can ensure that heated air reaches your living spaces efficiently, leading to more consistent temperatures and lower energy consumption.
In this post:
Your office might as well be a walk-in freezer.
The hallway outside is not much better.
But the rest of your home is quite toasty.
Yet, you’re still in the cold.
Your propane furnace might be fine—your heating ducts are not.
How Heated Air Slips Away Before It Reaches You
Your home’s HVAC system moves heated air through a network of ducts to deliver comfort to every room.
But when ducts leak or go uninsulated, much of that heated air escapes into:
- Attics
- Crawlspaces
- Basements
That’s how you end up heating spaces you don’t use while the rooms that matter stay chilly—all the while unknowingly paying more than you want or need to.
Your ducts may be hidden behind walls, ceilings, and floors—but you can feel their effects:
- Inconsistent room temperatures
- Furnace or heater running longer than needed
- Excess dust or declining air quality
- Whistling, rattling, or air noise from duct areas
Return ducts can also pull cold air from unconditioned areas, forcing your furnace to reheat the air before sending it back out.
Up to 20-30% of heated air can be lost through ducts and return ducts. Sealing and insulating ducts helps stop that hidden waste—keeping your warmth where it belongs.
What Happens During a Duct System Inspection and Sealing
Fixing ductwork is NOT a DIY job.
Professional duct sealing pinpoints and repairs leaks, properly seals joints and transitions, and often insulates ducts that run through unconditioned spaces.
The result? That 30% of lost air is yours again.
A certified HVAC technician can help you get that conditioned air back.
Step 1: Inspecting the Duct System
The technician begins by examining your entire duct network: supply and return paths, joints, connections, insulation, and how the ducts are routed through attics, basements, and crawlspaces.
They use specialized tools to find leaks and quantify loss, such as:
- Manometer to conduct pressure tests
- Blower door/dump-fan to create a pressure difference to force air through the leaks
- Flow hoods to measure airflow coming from each vent
These tests reveal where your duct system is losing air and guide the best next steps for repair.
Step 2: Sealing the Ducts
After finding the leaks, the technician seals all gaps and holes using materials designed to create airtight connections:
- Mastic sealants (a thick, durable adhesive paste)
- UL-approved foil/metal tape (not hardware store duct tape)
- Aeroseal or aerosol-based sealants (for advanced applications)
Sealing prevents air from escaping before it reaches your rooms.
Step 3: Insulating the Ducts
Last comes insulation. Ducts that run through unconditioned spaces need insulation to slow down heat loss (or gain) as the air travels through them.
Technicians typically use:
- Fiberglass duct wrap (flexible, wraps around ducts, and is secured with tape or wire)
- Foam board or spray foam (applied around ducts in tight or hard-to-reach spaces)
On occasion, they may install pre-insulated ducts for maximum efficiency if the current ones need replacement.
Together, sealing and insulating your ducts can reduce whole-house air leakage by 11.4%.
Sealed Ducts Pay Off—Especially in PA Homes
Leaky ducts are more than just an efficiency issue—they cost you comfort, money, and air quality.
Once your ductwork is sealed and insulated, you’ll notice the difference fast:
- Reduce heating and cooling energy: reduce them by 10-16%
- Lower heating bills: your propane furnace isn’t running nonstop
- Improved comfort: no more freezing home offices
- Healthier air: keeps dust out of your HVAC system
- Smaller carbon footprint: reduces energy waste and emissions
This is particularly important for Pennsylvania homes, which oftentimes face ductwork challenges. The houses vary in age and build, from historic homes in Kennett Square to brand new modern houses in Chester Springs.
Many older homes were retrofitted with ductwork not originally designed into the structure. That means:
- Uninsulated ducts in attics or crawlspaces
- Aging, disconnected duct joints
- No sealing from the original installation
Even in newer homes, sometimes duct sealing and insulation is overlooked.
With our long, cold winters and hot, humid summers, HVAC systems have to work hard year-round, and these duct leaks do not make it easy.
Don’t Let the Heat Slip Away
You’ve been fighting invisible heat loss, shivering in your home office, not knowing what to do.
Start with a furnace inspection from Kauffman Gas to see what’s really going on.
As part of our inspection, we can test your furnace to tell if duct leaks may be wasting your heat.
We’ll help you understand your results and next steps.
Get efficient, reliable comfort back in your home.
FAQs
How do duct leaks affect my home’s heating efficiency?
Your home’s efficiency can decrease when heated air escapes through leaks, holes, or uninsulated ducts before reaching your living spaces.
This forces your furnace to run longer to maintain temperature.
Finding and sealing those leaks can save you money.
How much energy is lost through leaky ducts?
20-30% of heated air can be lost through duct leaks.
This means that a third of the energy you pay for may never reach the rooms you’re trying to warm.
What are common signs of duct leaks?
Some common signs of duct leaks include inconsistent temperatures between rooms, a continuously running furnace, noises like whistling or rattling from ducts, and more dust than usual.
If you’re experiencing these, have someone inspect your ducts.
Can you fix duct leaks yourself?
No. Duct sealing requires special tools and training.
Professional HVAC technicians use pressure tests, sealants, and insulation materials for a long-lasting, effective result.
Attempting DIY fixes could cause further damage.
How much energy can you save by sealing ducts?
Sealing ducts reduces air leakage by 11.4% and can cut heating and cooling expenses by 10-16%.
You’re throwing less money out the window and increasing the efficiency of your heating and cooling system.