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A Right‑J® calculation refers to performing a Manual J load calculation using Wrightsoft’s Right‑J software.
Manual J is the ACCA‑approved industry standard for determining the heating and cooling loads of a residential building. It ensures HVAC systems are sized correctly for comfort, efficiency, and code compliance.

What a Right‑J Calculation Does

• Determines Heating Load: How much heat the home needs in winter.

• Determines Cooling Load: How much cooling the home needs in summer.

• Accounts for:

  • Square footage and layout

  • Insulation levels (walls, attic, floors)

  • Window and door types, sizes, and orientations

  • Infiltration/ventilation rates

  • Local climate data

  • Internal gains (people, appliances, lighting)

Steps in a Right‑J Calculation

1. Collect Building Data

   • Floor plans, dimensions, ceiling heights

   • Construction materials and insulation R‑values

   • Window/door specifications

   • Orientation (north, south, east, west)

2. Input Data into Right‑J

   • Enter all building envelope details

   • Select climate zone or nearest weather station

   • Add occupancy and appliance load data

3. Run the Calculation

   • Right‑J applies ACCA Manual J8 algorithms

   • Produces block load (whole house) and optionally room‑by‑room loads

4. Review Reports

   • Heating BTU/hr requirement

   • Cooling sensible and latent loads

   • Recommended equipment sizing

   • Ventilation requirements

Why It’s Important

• Prevents oversizing (short cycling, humidity issues)

• Prevents undersizing (comfort problems)

• Meets building code and ENERGY STAR requirements

• Provides documentation for permits and inspections