Having the right size heating and ac unit in a home or building is important. Balanced Comfort can work with you or your designated Architect to calculate how much heating or cooling a house will need. Our ASHRAE certified mechanical engineer is ready to assist you with your next project.

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Manual J Load Calculation Services

A manual J load calculation is used to calculate not only how much heating and cooling a house or building will require throughout the year, but also determines the correct size of the heating and air conditioning units that will be required for those homes or buildings. In particular, the manual J load calculation takes into consideration a variety of different pieces of information.

  • The thermal characteristics of each wall, door, and window.
  • The location of the home
  • The number of occupants
  • The number of appliances and lights being used
  • Possible duct leakage

Once this calculation has been finalized, you then will be able to figure out the properly sized heating unit and air conditioning system for that home or building. There are many benefits of installing perfectly sized heating and cooling units.

  • If your units are undersized you simply will not be able to keep the heat in during the cold months and out during the hot ones.
  • If your units are oversized you will end up with the phenomenon known as short cycling, in which your units perpetually turn on and off since they cool or heat the house so quickly. Short cycling, however, will not only drive up your utility bills but will also significantly shorten the lifespan of your heating and cooling units.

The manual J load calculation is a tool developed by the Air Conditioning Contractors of America (ACCA). There are primarily two different methods used for an ACCA approved manual J load calculation:

Whole House Calculation

This method takes into account all of the various considerations listed above (the thermal characteristic of the walls and windows, etc.) within the entire house and makes its calculations based on these.

Room By Room Calculation

This is the most accurate method. Rather than taking into account the entire house at once, this method looks at the considerations within each room and makes a room by room analysis.

Contact Balanced Comfort for any HVAC design and load calculation services.