Ductwork replacement is a complex undertaking. Getting it right avoids costly delays and HVAC performance issues. You need a professional for ducting services to ensure a successful installation, but the planning process is just as important. Here are some pro tips for planning ductwork replacement to help you make informed decisions and get more out of your investment.
Duct Placement and Layout
The layout of your ductwork has a significant impact on cooling and heating system performance. Whenever possible, air ducts should follow the shortest path to a room. If a duct is too long, the room it serves may be too cold or too warm.
Aside from the shortest route, ducts should have as few turns as possible. Sharp turns can restrict airflow and increase static pressure, wasting energy. Air ducts should also be insulated and placed behind walls, above ceilings, or below floors to protect them from extreme temperatures and heat loss (or heat gain).
The Basics of Duct Sizing
Duct sizing is one of the most essential steps to ductwork replacement. If your air ducts aren’t sized properly, your HVAC system will struggle to move air, and your energy bills will increase. Improperly sized ducts can also strain your AC and heating units, leading to major repairs and early system replacement.
Your local HVAC contractor should never take any shortcuts when calculating duct sizes. Online duct calculators make it seem simpler but relying on them can lead to errors. A licensed contractor should perform a Manual D duct size calculation from the Air Conditioning Contractors of America (ACCA).
The ACCA’s guidelines for duct size calculations consider the following:
- Square Footage: A technician can measure the square footage of your home directly or by checking its floor plans. The length and width of each room are multiplied to get its square footage; if a room is oddly shaped, it’s divided into smaller rectangles to obtain accurate measurements. The numbers for each room are added together to determine the total square footage of your home.
- Cubic Feet per Minute: The HVAC unit’s capacity in tons must be known to calculate the cubic feet per minute (CFM) needed. First, the technician multiplies its tonnage by 400. The total is then divided by your home’s square footage to obtain the CFM, a primary factor in determining the duct size needed.
- Friction Loss Rate: A professional has the knowledge and training to measure the friction loss rate, which refers to the pressure loss in a channel like an air duct. Various factors must be considered, including duct length and the number of coils, grilles, turns, filters, registers, and dampers. Accurate measurements help to achieve optimal airflow.
The following signs can mean your existing ductwork isn’t sized correctly:
- Constant Noise: Whistling, rattling, or other noises can mean the ductwork can’t handle the volume of air being pushed through it.
- High Utility Bill: If your monthly energy bill is higher than expected, your HVAC system may be working harder to compensate for improperly sized ducts.
- Decreased HVAC Performance: Parts of your home may be warmer or cooler, airflow from vents farther from the HVAC unit may be less, and air pressure may differ in each room.
Materials Selection
Several types of ductwork materials are available. When planning ductwork replacement, you have an opportunity to find the best material for your home’s cooling and heating needs. The most common materials include galvanized steel or aluminum, which are strong and durable. Insulated fiberglass is well-sealed but can break down more easily over time. Flexible, easy-to-install options include plastic, polyester, and PVC.
Insulating Your Ductwork
Insulating air ducts maximizes efficiency, especially when they’re in unconditioned spaces. Uninsulated ducts in attics and garages can lose energy and heat, overworking your HVAC system. Your local contractor can explain the best-suited types of insulation for your home so your duct system works more efficiently.
Common types of duct insulation include:
- Fiberglass: An affordable option, fiberglass duct insulation is highly efficient. It is also flexible, making it convenient for use in round and rectangular ducts. When wrapped in aluminum or perforated foil, it absorbs sound very well.
- Polyethylene: Polyethylene duct insulation effectively minimizes heat loss or gain. This lightweight, flexible foam can be applied inside or outside of air ducts. Like fiberglass, it’s resistant to condensation but costs more to install.
- Mineral Wool: This high-performance thermal insulation is spun into fibers and bound into rigid or semi-rigid boards, batts, or blankets. It can be installed with a sheet metal liner. Aside from its thermal and acoustic insulation, mineral wool is also highly resistant to heat and fire.
Another insulation consideration is the R-value. The higher the R-value of a material, the more insulating it is against extreme temperatures. Recommended insulation values vary depending on the regional zone you live in. Minimum R-value requirements may also be set by local building codes and regulations.
Sealing Your Air Ducts
Before ductwork replacement, a contractor should consider how they will seal air ducts. It can help in the design process. For example, fewer connecting components can reduce potential leak points and result in better-sealed ducts. Longer duct sections can also help reduce air leakage.
Other sealing methods include securing duct sections with screws or other strong fasteners. In many cases, joints and seams can be sealed with mastic and fiberglass mesh. Leaky seams can be precisely located by performing an air leakage test, which should be a part of every ductwork installation project.
Choose Compatible Filters
A large central HVAC system may have multiple air filters. For effective filtration, every filter must be compatible, meaning it must match in type and size. Finding the right solutions requires a trained technician. They can perform calculations room-by-room that help find matching filters. This should be a part of the planning process, as all filtration elements can be in place once your new ductwork is installed and the HVAC unit is turned on.
Balanced Airflow
Including air balancing in your ductwork replacement plan ensures your supply and return ducts have the same airflow capacity. You also need the appropriate number of registers for the system. With balanced airflow comes the following benefits:
- Proper heating/cooling for each room.
- Reduced wear and tear, which increases your HVAC system’s lifespan.
- Improved indoor air quality, as mold is less likely to grow.
- Increased energy efficiency.
- Reduce utility and repair costs.
Cost of Ductwork Replacement
Your budget is also a big factor in planning ductwork replacement. This step does take time. However, if air ducts aren’t the correct size, you’ll have to pay to replace them. Every project is unique, but your contractor can provide an estimate once they evaluate your home. The main factors affecting the cost of replacing HVAC ducts include:
- Home Size: Larger homes typically need more ducts and more complex layouts; therefore, ductwork replacement is more expensive.
- Duct Location: Ductwork in more difficult-to-access locations, such as cramped crawlspaces, requires more work, so an HVAC contractor will charge more.
- Material: Some duct materials are on the low end of the price scale, while others are more expensive yet longer lasting and more efficient.
- Labor: A professional’s hourly rate and how long the project takes have a significant impact on the total cost of the project.
Call Trilogy AC for Ductwork Replacement
At Trilogy AC, our licensed contractors are experienced in AC, heating, and ductwork services. Our team provides high-quality solutions that improve comfort, energy efficiency, indoor air quality, and your HVAC system’s lifespan. From duct sizing to materials selection to duct sealing, they help make the right decisions and ensure ductwork replacement goes smoothly. Let us get started in helping you plan your project. Call (832) 662-0866 or contact us today.
