If you already own the tools, this DIY is a no-brainer.
Need professional help with your project?
Get quotes from top-rated pros.
What you'll need:
TOOLS
Tin snips
Reciprocating saw
Angle grinder
Duct cutter
Safety gloves
Safety goggles
Dust mask
Ear protection
Metal file
When it comes to modifying or repairing your HVAC (heating, ventilation, and air conditioning) system, cutting ductwork in place is a skill that can come in handy. Whether you need to resize ducts, make alterations, or fix damaged sections, this guide will walk you through the process of how to cut ductwork in place step by step. While it's essential to take safety precautions and use the right tools, cutting ductwork in place can save time and money compared to replacing entire sections. Read on to learn more.
Prepping to Cut Ductwork in Place
Before cutting ductwork in place, prioritize safety. Put on safety goggles, gloves, ear protection, and a dust mask to shield against debris and noise. Confirm that the HVAC system is powered off entirely before you begin to prevent accidental starts and keep you out of harm’s way. It's also wise to inspect the ductwork for signs of asbestos. If any suspicion arises, stop immediately and seek professional assistance to handle potential asbestos-containing materials.
Prep the Room
Create a well-lit and well-ventilated workspace. Adequate lighting ensures precision, while good ventilation minimizes the inhalation of dust and fumes. Then, clear the area of any obstacles and ensure there's enough room to maneuver comfortably. Lay down protective coverings, such as tarps or drop cloths, to safeguard your flooring from metal shavings and debris. Having a clutter-free workspace enhances your focus and safety.
Measure and Mark Carefully
Photo: Tomasz Zajda / Adobe Stock
Accurate measurements are the cornerstone of successful ductwork modifications. Use a measuring tape and pencil to mark the specific sections you intend to cut. Double-check these measurements to avoid errors. Precision at this stage significantly simplifies the cutting process and ensures the new ductwork fits seamlessly into place.
Choose the Right Cutting Tool
Select an appropriate cutting tool based on the thickness and type of the ductwork. Tin snips are excellent for smaller cuts and precise adjustments. For larger or more robust ducts, a reciprocating saw or an angle grinder equipped with a metal-cutting blade offers efficiency and accuracy. The right tool makes a substantial difference in the quality of your cuts and the overall success of the project.
Make the Cut
Photo: djevelekova / Adobe Stock
Now it’s time to start cutting. If using tin snips, carefully follow the marked lines, applying steady pressure. For power tools like reciprocating saws or angle grinders, ensure a secure grip and guide the tool steadily along the marked lines. Pay attention to your technique, aiming for clean, straight cuts. Precision here directly impacts the ease of installation for the new duct sections.
Inspect and Clean Up
After making the necessary cuts, inspect the edges of the ducts for any sharp or uneven spots. Smooth out these edges using a metal file to prevent injuries during installation. Dispose of the cut pieces responsibly, and clean the air ducts and area thoroughly. Remove metal scraps, dust, and debris from your workspace. Store your tools safely, returning them to their designated places. A well-maintained workspace ensures future projects start on a clean slate.
Install the New Duct Sections
Photo: Serhii / Adobe Stock
If you're replacing a section of ductwork, you will have to fit the new piece into the cut-out area. Use appropriate fasteners, such as screws or bolts, to secure the new section to the existing ducts. Insulate the seams with foam insulation tape, ensuring an airtight seal.
Proper installation is crucial for efficient airflow, so take your time to align and secure the new sections accurately. Improperly installing these sections can lead to poor heating/cooling, an overworked system, and high energy bills.
Test the HVAC System
Once the new duct sections are in place, it's time to test your HVAC system. Power it on and observe the airflow. Listen for any unusual sounds and check for air leaks around the modified areas (here is a quick lesson on how to do a DIY duct leakage test). Ensuring the system functions correctly validates the success of your ductwork modifications.
DIY vs. Hiring a Pro
When it comes to cutting ductwork in place, the decision between DIY and hiring a professional involves a balance of cost, expertise, and time. DIY enthusiasts can save significantly on labor costs, focusing mainly on the price of materials and tools, which range from $100 to $300. However, the DIY approach requires time, patience, and the right skills. It's essential to invest in quality tools and safety equipment, ensuring precision and safety throughout the project.
On the other hand, hiring a professional HVAC technician can provide peace of mind and expertise. Professionals often charge between $200 to $500 for labor, making the total cost, including materials and labor, range from $400 to $800. Professionals bring years of experience and have all the necessary tools to ensure the work is done efficiently and correctly. They can save you time, energy, and potential frustration.
If you already own the supplies, you can save a lot by going the DIY route, but if you need to start from scratch, you may find paying a bit more to hire a professional duct installer near you is worth the extra money.
Frequently Asked Questions
Cutting round ductwork requires precision and the right tools. A duct cutter, specifically designed for circular ducts, is ideal. First, mark the cutting line on the duct using a measuring tape and pencil. Then, position the duct cutter's blade on the marked line. Apply steady pressure, rotating the cutter around the duct. The sharp blade creates a clean, precise cut. Alternatively, a reciprocating saw with a metal-cutting blade can be used for larger round ducts. Ensure the duct is securely held in place while making the cut to prevent slips and maintain accuracy.
The best tool for cutting metal ducts depends on the duct's shape and thickness. For round ducts, a duct cutter provides accurate, clean cuts. Reciprocating saws equipped with metal-cutting blades are versatile and suitable for both round and rectangular ducts. They offer speed and precision, especially for thicker metal.
Tin snips are handy for intricate cuts or smaller ducts. However, an angle grinder with a metal-cutting wheel is powerful and efficient for large or thick metal ducts.
Cutting rectangular ductwork requires careful measurements and the right technique. Use a measuring tape and pencil to mark the cutting lines accurately. Tin snips are excellent for straight cuts on smaller ducts. For more extensive or thicker rectangular ducts, a reciprocating saw with a metal-cutting blade is effective.
Ensure the duct is well-supported and secure while cutting to prevent wobbling and maintain precision. After cutting, use a metal file to smooth any sharp edges, ensuring safety during installation.
Yes, you can cut flexible ducting to the precise measurements you need. Stretch out the piece of ductwork, mark the length you need with a permanent marker, and use a long knife or hacksaw to cut through the material. Then, use a file to smooth out any rough edges before installing the duct.
Jacqueline DeMarco, a Northern California-based freelance writer specializing in sharing home decor and DIY tips, particularly focused on organizing and decorating small spaces. She has contributed to sites like Apartment Therapy, The Everygirl, and Orchard.
Jacqueline DeMarco, a Northern California-based freelance writer specializing in sharing home decor and DIY tips, particularly focused on organizing and decorating small spaces. She has contributed to sites like Apartment Therapy, The Everygirl, and Orchard.
The homeowners guide to Heating and Air Conditioning
From average costs to expert advice, get all the answers you need to get your job done.
