When you picture the comforts of summer in Austin, it’s easy to focus on the sleek thermostat on your wall or the hum of a brand-new condenser outside. But the star of the show—the network that actually delivers all that cool air—is your ductwork. Because it’s hidden above ceilings and behind walls, homeowners often underestimate how vital a flawless installation really is. To keep you from dealing with weak airflow, sky-high energy bills, or a never-ending dust party, here are the biggest mistakes to steer clear of when installing central AC ductwork—and how to dodge them like a pro.
1. Skipping a Proper Load Calculation
Don’t let anyone tell you that “eyeballing” room sizes is close enough. A Manual J load calculation considers square footage, insulation levels, window orientation, and even Austin’s infamous heat index. If your installer guesses, you could end up with undersized ducts that choke airflow or oversized trunks that never reach optimum velocity. Either way, efficiency tanks and comfort suffers.
2. Choosing the Wrong Duct Size or Shape
Round, rectangular, oval—each style has its own friction rate and space requirements. Homeowners sometimes default to whatever fits between joists, but a mismatch can create pressure imbalances. When ducts are too small, air whooshes loudly and the blower strains. When they’re too big, velocity drops, and conditioned air never travels the full distance. Your installer should size each run using ACCA Manual D calculations, not guesswork.
3. Forgetting to Seal and Insulate
Even perfectly sized ducts waste energy if joints are left unsealed. Mastic or UL-181 foil tape is non-negotiable—regular cloth duct tape peels off in Texas heat faster than you can say “high utility bill.” After sealing, R-8 insulation (the local code minimum) keeps attic temperatures from cooking your cooled air before it reaches the rooms below.
4. Poor Placement of Supply Registers and Returns
Putting supply registers behind heavy furniture or forgetting to add proper returns in each major living area disrupts circulation. You’ll notice temperature swings from room to room, forcing your AC to over-cycle. A well-planned layout balances air delivery and extraction so every corner of your home feels equally comfortable.
5. Excessive Turns, Long Runs, and Dead-Ends
Every elbow, reducer, and tee adds resistance. Ducts should follow the shortest, straightest path possible. Long spaghetti runs or abandoned “future” branches trap dust, encourage mold, and sap airflow. A streamlined design saves on both installation costs and monthly energy use.
6. Using Bargain-Basement Materials
Galvanized steel and quality flexible ducting almost eliminate air leakage when installed correctly. Thin, off-brand flex lines or recycled sheet metal seem thrifty at first, but they tear, sag, and separate under attic heat. You’ll pay far more in repairs and wasted energy down the road.
7. Ignoring Building Codes and Permits
Austin’s code department isn’t just red tape—they’re your first line of defense against unsafe work. Bypassing permits risks fines, insurance headaches, and, worst of all, hidden fire hazards. Reputable installers welcome inspections because they know their work will pass.
8. Skipping the Final Test-and-Balance
Good installers don’t pack up after the last duct hanger is screwed in. They measure static pressure, tweak dampers, and verify CFM at each register. This commissioning step ensures your new system hits the efficiency ratings on the box—and gives you a baseline for future maintenance checks.
The Smart Way Forward
Avoiding these pitfalls might sound like a full-time engineering gig, but you don’t have to tackle it alone. Central AC Ductwork Installation is widely recognized as the best ductwork installation service in Austin, TX, because they obsess over the details homeowners miss. From laser-accurate load calculations to airtight sealing, their team treats every attic like a custom project, not a cookie-cutter job. If you’re planning a new system or replacing leaky old ducts, give them a call. Your future self—relaxing in perfectly balanced, cool air—will thank you.