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How to Achieve Good Ductwork Design

ductwork designThe air ducts in your Vidor area home perform more tasks than just holding air. They serve as the avenue for heated and cooled air and increase the quality of your home’s indoor air. As a result, good ductwork design isn’t a luxury; it’s a necessity. 

How to Plan Good Ductwork Design Step By Step

When you’re planning a new home or an addition to it, you need to include a mechanical contractor early in the process so that your heating, ventilation, and air conditioning (HVAC) systems are integrated into the home, rather than being patched in as afterthoughts. 

A mechanical contractor will work with your architect or general contractor to ensure good ductwork design leads to real energy savings and efficient use of a new furnace and central air conditioner. The process begins with a few manuals. 

Start Ductwork Design Process with Manuals J, S and D

The Air Conditioning Contractors of America (ACCA) association produces three manuals guiding the selection and installation of HVAC equipment. An experienced mechanical contractor begins with Manual J to calculate each room’s heating and cooling load. These calculations take into account such things as the number of windows, expected room usage, expected number of occupants, orientation (southern-facing rooms gain more free radiant energy from sunlight) and even the anticipated landscaping outside. 

Manual J tells the contractor what levels of heating and air conditioning will make the home comfortable for years to come. The heating and cooling loads lead to Manual S, in which the exact models of furnace and central air conditioner are determined. 

Possible Ductwork Additions

At this stage, engage with your mechanical contractor to discuss desirable options for the HVAC equipment: 

  • Thick media air filter
  • Whole-house humidifier
  • HEPA air filtration
  • Zoning and programmable thermostats
  • UV germicidal lights
  • Electrostatic air filter
  • Air-handling equipment

Some of these additions may be necessary if anyone in your home is sensitive to indoor air quality issues. All of these additions change airflow requirements and can affect the efficiency of the heating and cooling units. Manual S helps a contractor select the perfect size equipment — too big wastes energy and money while too little makes for an uncomfortable home. From Manual S, the contractor moves to Manual D, which yields good ductwork design. 

Benefits of Good Ductwork Design

The goal of a good HVAC installation is invisibility and efficiency so that you don’t even realize it’s there while it’s working. You just enjoy living in a comfortable, clean home. Good ductwork design contributes to that in several ways:

  • Ductwork will be silent on furnace or central air conditioner startup
  • Fewer visits for duct cleaning
  • No room will be too hot or too cold
  • No room will feel blasts of air
  • Airflow throughout the home will be efficient
  • Furnace and central air conditioner won’t be overworked

Good ductwork design works smoothly with the home’s architecture and ensures maximum efficiency in airflow and equipment use. For example, no ducts should run in exterior walls, and all ducts should be invisible in occupied areas. 

Install the Ductwork Correctly

Once Manual D determines the right cross-section (amount of air each duct must move) for each room, the manual contractor routes the ducts for maximum efficiency and minimal intrusion. Registers and vents are located for ideal airflow. Optional equipment is located correctly in the plans. 

Some contractors, eager to move on to another job, will minimize crew time and labor by replacing the designed duct sizes for branch ducts with six-inch flexible ducts off the main duct. Ensure every duct, main and branch alike, is installed according to Manual D calculations. 

Duct sealing should be done with mastic. This reduces dust intrusion and prevents untreated air from entering the ducts. Check that ducts are securely fastened to the home structure at registers and vents. This minimizes vibration at startup. 

Perform Duct Maintenance

An experienced HVAC contractor will follow up installation with some quality control checks such as a blower door test. Maintenance after the installation should include system balancing, an annual cleaning and inspection, as well as a check to see if dust has built up in the ducts. 

For more ideas on good ductwork design, contact us at Thermacon Service Company

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