Manual J Residential Load Calculation. What is it? What does it cost? How long does it take?

Published by Jobe Leonard of and the Reschexpert blog. Jobe enjoys all things related to Rescheck reporting and the study of home energy audit softwares for creating Reschecks, Comchecks, and Manual Js.

Jobe Leonard

Jobe Leonard

Today on the Reschexpert blog we want to discuss, what is a Manual J Residential Load Calculation? What is it? What does it cost? How long does it take?

Manual J is a calculation method used to determine the heating and cooling load of a residential or commercial building. It is the most widely used method for sizing HVAC equipment in the United States. The calculation takes into account the following factors:

  • The size and orientation of the building
  • The climate zone your project is located in.
  • The insulation levels of your ceiling, walls, windows, skylights, doors, and foundation.
  • The number of occupants that will be in your structure.
  • The type of appliances and lighting that will be located in your home.
  • The solar gain or amount of heat that the sun’s energy adds to your house

The results of the Manual J calculation are used to determine the size and capacity of the HVAC equipment needed to maintain a comfortable temperature in the building, when combined with a Manual S equipment sizing report.

Manual J Service (Step by Step Guide)

Manual J is a complex calculation, and it is often done by HVAC professionals like However, there are also software programs and online calculators that can be used to do the calculation. These vary in cost from free Manual J calculators with varying degrees of accuracy, all the way to $5000 Manual J software suites.

The cost of a Manual J calculation varies depending on the size and complexity of the building. In general, it costs $79 when it is prepared by

The total amount of time needed for a Manual J calculation is 4-6 hours when it is prepared by

If you are considering having a Manual J calculation done, it is important to email your PDF plans, jobsite address and square footage to You should also make sure that the contractor is qualified to do the calculation and that they use a reputable software program or calculator.

Manual J versus Manual S

Here are some of the benefits of doing a Manual J calculation:

  • It can help you to avoid oversizing or undersizing your HVAC equipment (in conjunction with a Manual S equipment sizing).
  • It can help you to save money on your energy bills. Our Manual J shows what time of day the sun’s energy will have the most affect on your home.
  • It can help you to ensure that your HVAC system is operating efficiently.
  • It can help you to comply with building codes. Many building codes like IECC 2009, IECC 2012, IECC 2015, IECC 2018, IECC 2021, and IECC 2024 will require a Manual J Heat Loss and Gain Report.

Comcheck versus Manual J

If you are planning to install a new HVAC system or upgrade your existing system, it is a good idea to have a Manual J calculation done. This will help you to choose the right size and capacity of equipment for your needs and ensure that your system is operating efficiently. Email PDF plans, jobsite address, and square footage to and we will get you taken care of.

Review Date
Reviewed Item
Manual J Residential Load Calculation
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Software Name
Free ACCA Manual J Residential Load Calculation
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Free ACCA Manual J Residential Load Calculation