How to Confidently Create a Duct Renovation Scope of Work w/ David Richardson

Residential air balancing is largely a development of National Comfort Institute’s (NCI’s) late, great Rob Falke, and it was a major step forward for performance-based HVAC system design. Nowadays, we can think of HVAC systems as puzzles with four large pieces and several smaller ones each; the four broad categories are design, installation, verification, and communication. HVAC professionals bring life to the system during the installation; incorrect installations lead to premature system failure.

Duct renovation is not easy work, but it is a profitable upgrade for homeowners. Older duct renovation practices started and ended with repairs, but we can give customers much better HVAC systems by following a detailed process of testing, diagnosing, and prescribing a solution before repairing.

During the starting phase, perfectionism is a common obstacle for many technicians who worry about missing their airflow targets; we need to prioritize progress over perfection. Other obstacles include customers that are unwilling to purchase duct renovations, expensive tools, and the labor shortage. Scheduling can mitigate some of these, as seasonal price fluctuations (lower in shoulder seasons and winter) and lighter winter schedules can make duct renovation more attractive for your company and the customer.

There are two duct renovation approaches: air upgrades and duct optimization. Typical air upgrade features at the equipment include reducing static pressure drop across the filter, improving duct fittings, system cleaning, adjusting fan speed, and charging/recovering refrigerant. Air upgrades in the ductwork include adding one oversized return duct and grille into a large area, using 8” ducts with balancing dampers, sealing leaky ductwork, supporting the ducts with proper strapping, replacing restrictive fittings, and upgrading the grilles and registers. Duct optimization requires us to customize an existing duct system so that it can deliver individual rooms’ BTU targets, often including the installation of balancing dampers and grille and register upgrades.

Testing is the starting point for a duct renovation. You can get a solid start by performing airflow tests. Thermal imaging cameras are also useful tools to look for signs of building envelope leakage that needs to be addressed.

The five basic rules for duct renovation are (1) don’t renovate ducts on oversized equipment, (2) involve the customer in the process, (3) focus on one thing, (4) get paid for the time and effort you put into your designs, and (5) use all the puzzle pieces (i.e., go through all of the testing and steps required to produce a duct renovation scope of work).

As with the basic rules, there are five questions to ask about any duct renovation: (1) Why are you there? (2) What are you trying to accomplish? (3) What does the customer want you to solve? What is their pain? (4) What access do you have? (5) How many people need to be involved in the renovation (for communication purposes)?

For best results, make sure you know your customers’ goals and let them make decisions. You’ll also need to make sure information is communicated effectively between salespeople and installers (and anyone else who is involved in a duct renovation). As you serve your customers, you may have to renovate some systems you installed due to improvements in technology and our understanding of HVAC design over time; duct renovations on systems you designed should not be free.

David presents seven steps for a duct renovation: (1) perform a visual inspection of the entire system and the building, (2) measure the system to identify duct inefficiencies, (3) diagnose your readings, (4) conduct an interview with your customer, (5) communicate the scope of work to the customer and your team, (6) perform the duct renovation, and (7) test out and generate an assurance report.

A visual inspection gives you the opportunity to find issues in plain sight that you’ll want to address. After your visual inspection, start taking readings of the HVAC system’s “vital signs,” including total external static pressure, component pressures (coil and filter pressure drops), duct pressures, fan airflow, and system airflow. You will use those readings to diagnose the problem.