What Is a Manual D and J

Manual D — This procedure is used to design ductwork for a new HVAC system. It can only be done after Manual J is used to determine the heating or cooling load in each room. The ducts must be designed carefully to match the HVAC system; otherwise airflow velocity will be too great or too little.

Is manual D required?

DUCT DESIGN & SIZING In many municipalities, Manual D is a mandatory requirement.

What is manual D load calculation?

What is Manual D? Manual D is the industry standard for sizing home HVAC return and supply duct & registers. Manual D duct design distributes the correct amount of heating and cooling to each room based on the Manual J load calculation results.