The ventilation system in your home is responsible for keeping your home comfortable, but it’s one of the most overlooked HVAC systems.
The ductwork distributes air within your heating and cooling system to keep your indoor living areas conditioned.
But if you have leaking air ducts, you are also conditioning spaces that you might otherwise not want to condition.
These could be basements, attics, crawl spaces, wall cavities, etc.
These can manifest themselves in various ways, which we will cover shortly.
Keep reading to learn more about air duct leaks, how to spot them and what you can do to fix them.
🌬️ What Are Duct Leaks?
Duct leaks occur when air within your duct system leaks through cracks, gaps, and seams in your ductwork system.
University of Florida research states that “leaky ducts make your HVAC work much harder—ducts leaking just 20% of the conditioned air passing through them cause your system to work 50% harder.”
That’s significant when you spend your hard-earned dollars on heating or cooling.
There are three types of duct leaks.
Understanding these will help you efficiently track down leaks and figure out a fix.
🔧 Supply Leaks:
Supply leaks occur with the supply air ducts. These ducts move conditioned air from your indoor air handler to the living space.
🔧 Equipment Leakage:
This occurs in and around the core of your central air conditioning system. If you have a central HVAC system, this would be the indoor air handler, sometimes known as furnace cabinets.
🔧 Return Leakage:
This occurs when unconditioned air around the ducts gets sucked into the ductwork and moved back into the airflow, returning to the indoor air handler.
This strains your HVAC system as you are not conditioning air from unconditioned spaces instead of reconditioning air that’s already been through the heating or cooling cycle.
🌬️ How Do You Know if Your Ducts Are Leaking?
There are a couple of things to look out for when trying to ascertain whether you have a duct leak in your home.
Here are the top three signs of leaking air ducts.
🔧 Higher Utility Bills
Higher energy bills seem to be all the rage lately.
But if you see a spike in your bills, your AC or furnace might use more energy for the same output.
Leaky ductwork can have a huge effect on your system’s energy efficiency.
If your air ducts are leaking and reflected in your energy bill, then it’s time to fix them.
🔧 Hot and Cold Spots In Your Home
Are you having difficulty cooling rooms in summer and heating them in winter? Do you also have cold or hot spots in specific areas of your home?
This is a major sign of an air duct leak.
Depending on the air leak, you will experience reduced airflow in certain rooms, causing some areas to feel hot or cold simultaneously.
🔧 Poor Indoor Air Quality
Leaking ducts can have a major effect on your home’s indoor air quality.
If your leaky ducts pull nonconditioned air from crawlspaces or attic, you are introducing a lot of dust and debris into the conditioned airflow.
In fact, Energy Star stated that 20 to 30 percent of air traveling through ducts is lost due to leaks, holes and poorly connected ducts.
✅ PRO TIP: Constantly clogged air filters are a dead giveaway that you have a leaky duct.
🌬️ Tips on How to Conduct a Visual Duct Leakage Test
🛠️ Run your HVAC System on High
You can do a quick visual check for air leaks by running your air conditioning or heating on full blast.
This will quickly show up duct leaks.
🛠️ Visual Ductwork Inspection
Check your ductwork for obvious holes or tears.
Mark problem areas with a grease pencil to help you remember where you found them.
Once the visual inspection is complete, you can come back and fix them.
Or give your local HVAC professional a heads up to help with their repair.
Also, check your air filter. If dust and debris have been introduced into the airflow, hopefully, your air filter is capturing it.
It will clog quicker than usual with duct leakage.
🛠️ Carefully Check Duct Joints
Duct joints are notorious for being the source of an air duct leak.
Joints are where ducts meet and are not always sealed correctly or have shifted over time.
Run your hand over them when doing your visual inspection with your HVAC system on.
🛠️ Check For Existing Duct Tape
If you weren’t the first person to own your home, there might be duct tape on your ducts highlighting a previous attempt at repair.
Contrary to its name, duct tape isn’t actually for repairing ducts.
As you are conducting your visual duct leakage test, be sure to take note of any duct tape you find and check for leaks.
If there is a leak, it will need to be repaired. But not with duct tape!
🛠️ Use a Smoke Pencil
A smoke pencil is what professionals use when looking for air leaks.
It produces a small stream of visible smoke that you use to check for leaks.
If a leak is present, the smoke trail will either be pulled into the duct or blown away if it’s an outward leak.
These are great at finding less obvious leaks. You could also use an incense stick the same way.
Mark the air leak with that grease pencil so it can be addressed later during the repair.
🛠️What To Do If My Ducts Are Covered With Insulation?
There is no easy answer to this question.
You will have to pull up all the insulation around ducts and vents to have access.
Insulation that’s moved or been blown away may identify the leak if it’s a large enough leak.
Once you have finished your visual inspection, you can replace the insulation.
Be careful not to put the insulation back if any of your ducts have been sealed with liquid products and isn’t quite dry yet.
Related Reading: Homeowners Guide to Duct Insulation
🌬️ Call in an HVAC Professional
Some leaks might be obvious, while others are not.
The leak may not be in an easily identifiable area with the above techniques.
This is where a professional is required to conduct a duct leaking test.
HVAC technicians know what they are looking for and all the tips and tricks for correctly identifying and repairing leaks.
A duct leakage test involves connecting your ductwork to specialized equipment that uses a computer and a fan to measure airflow.
The technician will then repair the leaks with either of these three duct treatments or a combination of the first two:
- Specialized Tape
- Mastic Sealant
- Aeroseal Treatment
Related Reading: Duct Repair: A Homeowners DIY Guide
🌬️ Why Do We Want Sealed Ducts?
💰 Save Money!
You can save a bunch of money on your energy bills by sealing duct leaks.
Your furnace, air conditioner, or heat pump doesn’t have to work as hard to move heated or cooled air around your home to meet your desired temperature.
🛠️ Avoid Costly HVAC Repairs
Duct leaks increase the chances of a future problem with your heating and cooling system.
Constant run time can reduce the lifespan of your HVAC system.
Introducing air pollutants such as dust and other debris into the conditioned airflow can easily contribute to more frequent breakdowns.
🏭 Maintain Good Indoor Air Quality
Air leaks in your ductwork can suck up a whole range of bad stuff from attics and crawl spaces, all of which contribute to poor indoor air quality.
You don’t want that stuff floating around in the air for you and your family to breathe, especially if any one of them has allergies or suffers from asthma.
Related Reading: How to Improve Your Indoor Air Quality
Related Reading: IAQ Guidelines for Single-Family Renovations
🌬️ How Do You Fix a Leaky Air Duct?
Our advice: call a local and reputable HVAC company for professional testing and duct sealing services.
Even if you follow the steps above, it can be difficult to find those smaller leaks in not so easy to get to places.
If you have completed a though inspection and find that you still have leaks in your air duct system, it’s time to call a duct leakage expert.
They have the know-how and the equipment to find leaks beyond a visual inspection.
You will be surprised what a positive impact fixing a leaky air duct can have on your HVAC system performance.
If you live in or around Central and North Okanagan regions, check out Phyxter Home Services.