Duct Replacement & Sealing

In most Austin-area homes, the air handler and ductwork sit in a vented attic that can top 130°F on a summer afternoon. Every leak in a supply duct pushes cooled air into that attic. Every leak in a return duct pulls hot, humid, dusty attic air into your system. ENERGY STAR estimates that a typical home loses 20 to 30 percent of the air moving through its ducts to leaks, holes and poorly connected ducts. Here, that shows up as long run times, rooms that never cool off and humidity that will not come down.

Ducts also pick up heat through their walls. Thin, damaged or missing duct insulation means air that left the coil cold can arrive at the register noticeably warmer.

Most homes in the Austin area use flexible duct. Installed right, pulled tight, supported at proper intervals and run with gentle bends, it performs well. Installed poorly, or left alone for years, it sags between supports, kinks around framing and gets crushed during other attic work.

Every sag and tight bend adds resistance and cuts airflow to that room. Over time the outer jacket can become brittle in attic heat, and connections at boots and collars can loosen or pull apart. Pinching straps, runs far longer than needed, and ducts lying on hot attic surfaces are all problems we find and fix.

Not every duct problem needs new ducts.

• Sealing makes sense when the ducts are in reasonable shape and sized correctly. Sealing leaks at the plenums, boots, collars and connections with mastic and proper tape can make a big difference, and it is usually faster and less expensive than replacement.
• Replacement makes sense when ducts are crushed, torn, deteriorated, contaminated or badly undersized, or laid out so poorly that sealing will not fix the comfort problem. It is also the time to fix design problems, such as adding a return, resizing trunks or moving registers.

We will explain what we found and recommend the fix that actually solves the problem.

If your ducts are in good shape and just dirty, air duct cleaning may be all you need.

ACCA Manual D is the industry-standard method for designing duct systems. It uses the room-by-room loads from a Manual J calculation and the blower’s available airflow to size each trunk, branch and return so every room gets the air it needs. Many existing Central Texas homes were never designed this way.

When we replace ductwork, we design it instead of copying what was there. A well-designed duct system also lets a new high-efficiency AC or heat pump deliver the performance it is rated for. Learn more in Smart HVAC Design: Manual J, D and S Explained, and see our ductwork services and AC services.

The main things that drive the cost of duct work are:

• The size of the home and the number of supply and return runs
• Sealing only, partial replacement or full replacement
• Attic access, height and working conditions
• Design changes, such as added returns or resized trunks
• Replacing plenums, boots and registers
• Mold protocol requirements, if any

Call for a quote at 512-489-4653 or schedule online. Austin Energy customers may qualify for rebates on duct sealing through its whole-home efficiency programs; see our rebates page and check current terms.

Want to understand your options before you call? Our homeowner guides on ductwork are written by our team for Central Texas homes.

• Smart HVAC Design: Manual J, D and S Explained
• Understanding Your Home’s Duct System
• Why Properly Sized Ductwork Matters
• Duct System Optimization: Boosting Efficiency and Comfort
• Where Your Home Actually Leaks: A Central Texas Guide to Air Infiltration

Browse all homeowner guides in the Gold Eagle Resource Center