Manual N — Commercial Load Calculations
We prepare Manual N load calculations for commercial buildings of every kind across the USA.
What is Manual N ?
Manual N formally known as the Commercial Load Calculation — is the ACCA-approved method for determining the precise heating and cooling loads in light commercial buildings up to around 3 stories. It accounts for the unique thermal characteristics of commercial spaces: higher internal heat gains from equipment and occupants, variable occupancy schedules, diverse space types under one roof, and commercial-grade envelope assemblies.
The result is a room-by-room and zone-by-zone load profile that tells your mechanical engineer or HVAC contractor exactly how much capacity each area of the building requires — so equipment is sized correctly, energy costs stay in check, and occupants stay comfortable.
What we need to prepare your load calculation:
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Floor plans — dimensions and ceiling heights for every room and zone, all levels
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Envelope specs — wall, roof, and floor assembly R-values or construction details
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Window & door schedule — size, orientation, U-factor, and SHGC for each unit
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Project address — for local design temperatures and climate zone data
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Space use & occupancy — type of business, number of occupants per zone, hours of operation
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Internal heat sources — lighting wattage, major equipment, and appliances generating heat in the space
Why HeatLoad USA?
Since 2008, we've prepared thousands of Manual N reports for HVAC contractors and builders across all 50 states. Our reports are accurate, code-compliant and accepted by building departments nationwide.
Certified by ACCA we are one of the few firms qualified to prepare both residential (Manual J) and commercial (Manual N) load calculations.