By Commercial Service Company · November 4, 2026
You run the thermostat, the rooftop unit kicks on, and the dining room still feels off while the office down the hall is freezing. Before anyone assumes the unit itself is failing, it's worth looking at what's happening between the equipment and the room: the ductwork. In a lot of commercial buildings around central Arkansas, leaking supply and return ducts are quietly pulling conditioned air out of the system before it ever reaches the space it's meant to cool or heat.
Ductwork doesn't get much attention because it's hidden above ceilings, behind walls, or run through unconditioned attics and mechanical spaces. But every joint, seam, and connection is a potential leak point. Over years of vibration, settling, temperature cycling, and the occasional bump from maintenance work in a ceiling, those connections loosen. Once that happens, your system is working to condition air that never makes it to the dining room, sales floor, or walk-in cooler area.
How Duct Leaks Waste Conditioned Air
A duct system is only as good as its seal. When a supply duct leaks, cooled or heated air escapes into a ceiling cavity, attic, or wall space instead of reaching the register. Your rooftop or split system still has to run long enough to satisfy the thermostat, so it cycles more often and for longer stretches to make up for what's being lost along the way.
Return-side leaks cause a different problem. They pull in hot attic air, dusty ceiling air, or kitchen exhaust instead of pulling conditioned room air back to the unit. That mixed air throws off the system's read on actual room conditions, which can mean uneven heating and cooling throughout the building and a unit that runs more than it should just to keep up.
The Rooms That Suffer Most
Leaky ducts rarely cause problems evenly. You'll usually notice it in specific spots:
- Rooms at the far end of a duct run, where leaks upstream have already drained away part of the airflow
- Spaces below or near ceiling access panels, attic hatches, or recent electrical or plumbing work where ductwork may have been disturbed
- Dining areas or sales floors with high ceilings, where weak airflow is harder for customers and staff to ignore
- Back-of-house areas like prep kitchens or storage rooms, which often get the leftover airflow after the rest of the building is served
- Offices or breakrooms on long duct branches furthest from the air handler
If one part of your building never seems to match the thermostat setting no matter how the system is adjusted, duct leakage is one of the first things worth ruling out.
What a Technician Looks For
Diagnosing duct leakage isn't guesswork. A technician inspecting your system will typically check:
- Accessible duct joints, elbows, and takeoffs for separated or loose connections
- Flex duct sections for crushed runs, sagging, or torn outer jacketing
- Sealant and tape at seams that has dried out, cracked, or pulled away over time
- Airflow readings at registers compared to what the equipment should be delivering
- Pressure differences between rooms that suggest air is escaping before it reaches the space
- Return air paths for gaps that let in unconditioned attic or ceiling air
This kind of inspection usually happens alongside a broader look at the equipment itself, since duct problems and equipment strain tend to show up together. Any work involving electrical connections, refrigerant lines, or gas-fired equipment attached to the ductwork should always be handled by a licensed technician rather than in-house staff.
Why Sealing Ducts Pays Off
Sealing leaks and reconnecting loose joints keeps the air your system conditions actually moving to where it's needed. For an occupied building, that generally means more even temperatures from one room to the next, less strain on the equipment trying to compensate for lost airflow, and a system that doesn't have to run as hard or as long to hit the same setpoint. Over time, less runtime on a unit also means less wear on components that are expensive to replace.
Sealing ductwork isn't a one-time fix you do and forget, either. Buildings settle, ceiling work happens, and connections loosen again. Having duct condition checked as part of a regular equipment inspection catches small leaks before they turn into a comfort complaint or a bigger utility bill.
If certain rooms in your restaurant, store, or facility never seem to get enough heating or cooling, or your system seems to run constantly without catching up, give Commercial Service Company a call at 501-548-2374. We'll take a look at your ductwork and equipment and tell you plainly what's going on.