How to Size HVAC Ducts

Save

HVAC duct sizing can seem like a challenging task. If the duct is too small, air velocity will be too high which will cause increased restriction, decreased airflow and noise in your HVAC system. If the duct is too large, air velocity will be too low which will cause premature warming/cooling of the air and low airflow through your HVAC registers. However, with the proper resources, HVAC duct sizing is a fairly easy thing to determine.

Things You'll Need

  • Ductulator or computer with Internet access

Instructions

  • Purchase a Ductulator. Trane makes a wonderful one that retails for around $13.00. (See Reference 2.) As a lower cost alternative, there are a few websites out there where you can perform the same calculations. (See Reference 1.)

  • Figure out the CFM (cubic feet per minute) you want to flow through your duct. You want to maintain your airflow between 600 and 900 FPM (feet per minute). Higher than that will cause noise and decreased efficiency. Lower than that will cause premature warming/cooling of the air and decreased efficiency.

  • Using the Ductulator, or online calculator, match the CFM requirement to the friction rate you plan on using. Standard friction rate is 0.1" water column per 100 feet. It will then give you an equivalent duct size in both rectangular duct and round duct.

  • Purchase and install the duct size that is given to you by the Ductulator or online calculator.

Related Searches

References

Promoted By Zergnet

Comments

You May Also Like

  • How to Calculate CFM in HVAC

    In order to have a comfortable living space or room, you need to have a properly designed HVAC system. If you have...

  • How to Size a Flex Duct

    Flex duct allows easy connection from the main duct trunk to the HVAC grille. Without it, there would be tons more labor...

  • How to Calculate an Air Conditioning Duct

    Installing the right size HVAC duct is crucial for an efficient HVAC system. Ducts that are sized too large will have too...

  • How to Calculate Heating Duct Sizes

    To maintain a house's energy efficiency, the correct heating duct sizes are crucial. Some houses have ducts that are too large or...

  • How to Calculate Residential Duct Size

    Duct work that is an incorrect size can cause unnecessary noise, increased energy costs and lower air quality. Duct systems distribute air...

  • HVAC Duct Design and Calculation

    Calculating and designing the heating, ventilation and air-conditioning duct system for a home is a challenging task. Many considerations have to be...

Related Searches

Check It Out

22 DIY Ways to Update Your Home on a Small Budget

M
Is DIY in your DNA? Become part of our maker community.
Submit Your Work!