Does Ductwork Design Impact the Performance of a Furnace or AC Unit?

Yes – improper ductwork design will have a noticeable impact on temperature control in your home, especially when it comes to consistency. Ductwork issues combined with units that are under or overpowered can lead to a variety of problems, such as parts of your home far away from the HVAC unit receiving too little heated or cooled air circulation while vents closer to the unit push out too much hot or cold air.

Ductwork design is a vital component of overall system design, and there’s a specific science to the process of planning out an effective ductwork layout.

The Basics of Home Ductwork Design

There are a few key design considerations that are primarily responsible for the overall effectiveness of ductwork in a home:

• Sizing
• Layout
• Material selection

Although it’s not technically part of the ductwork design process, ensuring proper ductwork insulation and sealing can be equally important to the overall performance of the ductwork.

Ductwork Sizing

Ducts that aren’t big enough for the system’s output or appropriate for the size of the home will cause restricted airflow, which will put extra strain on the HVAC system and reduce overall system efficiency. Ductwork that’s too big will result in reduced air velocity, which will make circulation ineffective and reduce temperature control performance.

Ductwork Layout

There are two primary layout issues that can drastically reduce the consistency of vent output: sharp bends and long runs. The placement of the HVAC unit (or units) and the design of the ductwork should ideally minimize the use of either long runs or bends in the ductwork.

Material Choice

Not all ductwork materials are equal for every application – some materials are more expensive, more prone to degradation or damage over time or have lower insulation value. Common ductwork materials for homes include fiberglass, sheet metal and flexible ductwork.

Common Ductwork Design Mistakes in Arlington Homes

Improper Sizing

There are a number of factors that go into ductwork sizing decisions, including the HVAC system’s output and the length of the ductwork. Most residential HVAC units are compatible with either rectangular sheet metal ducts or round flexible ductwork. The diameter of round ductwork and the height and width of rectangular sheet metal ductwork is important for both performance, insulation and energy efficiency.

Unbalanced Air Distribution

Ductwork that’s not properly sized, meaning the diameter or the height and width measurements are too large or small, won’t be able to properly carry cooled or heated air at an adequate velocity to maintain a consistent temperature throughout the home. Your HVAC system may be forced to work harder than it would otherwise need to in order to maintain the temperature set on the thermostat throughout your home.

Long Duct Runs

Air in long run ductwork will lose pressure and volume as it travels further from the HVAC unit’s blower fan to the furthest vents in the home. In practical terms, the cooled air or heated air that reaches far away rooms won’t be the same temperature as the air coming out of vents closer to the furnace, air conditioner or heat pump. Depending on where the thermostat is located in your home, this could lead to inaccurate readings, with the temperature of some rooms being significantly higher or lower than the room with the thermostat and rooms closer to the HVAC unit.

Inadequate Return Ducts

HVAC output may be the more obvious indicator of system performance, as it’s the one variable you can feel, but returns play a vital role as well. Your HVAC system needs to pull indoor air through the return and reheat or cool it before circulating it back through the ductwork. Either not having enough return capacity or having returns poorly placed or obstructed can lead to insufficient return air pathways, leading to whole-home pressure imbalances.

Impact of Ductwork Design on AC Efficiency

Poor ductwork design can impair the efficiency of your home’s furnace or air conditioner, meaning increased energy consumption and higher utility bills. Your HVAC system will run more than it should need to as it attempts to maintain your desired temperature, which will accelerate wear and lead to reduced system longevity.

Get the Right Ductwork Design for Your Home

The team at Tom’s Mechanical has extensive experience in ductwork design and installation. We understand the most common duct issues that negatively impact HVAC performance and efficiency and know how to solve those problems. We’re also the local Arlington experts to call if you ever need reliable and safe duct cleaning services to enhance your indoor air quality.

If you need to replace the HVAC system in your Arlington home but think you may require ductwork redesign or repair, give us a call at 817-277-4493.