Wrightsoft is the original technical partner of the ACCA (Air Conditioning Contractors of America) for developing computerized versions of the Manual J and Manual D manuals. Our calculations are ACCA-certified, giving contractors the information they need to properly size an HVAC system for your home. A properly sized system will mean better air quality and energy efficiency for you and your family.

Manual J Load Calculations

Why are Manual J load calculations important?

• They are required for utility, local, and government rebates and incentives.
• Increasingly more and more building inspectors require them for meeting code requirements.
• To ensure you have a properly sized system for your home. Factors that need to be considered to ensure the proper size for your comfort needs include:
  • The local climate
  • The number of occupants
  • Size, shape, and orientation of the home
  • Window area, location and type
  • Building construction materials, including insulation
  • Air infiltration rates

Why is a properly sized HVAC system important?

• Energy Efficiency: If the system is too small or too large, you'll be paying more to operate it. If it's sized just right, it will run steadily and therefore be more affordable to operate.
• Comfort and Air Quality Assurance: An over-sized air conditioner will not adequately remove the moisture from the air, which can cause air-quaity issues like mold and mildew. An over-sized heating system will produce more air than necessary, creating drafts and discomfort.

Manual D Duct Designs

Why are Manual D calculations important?

• Manual D helps the contractor accurately size duct-work to ensure proper airflow from the heating and cooling systems, meaning the house will be sufficiently cooled and heated when needed to maintain comfort.
• Proper ductwork, when combined with an appropriately-sized system, will reduce operating costs.