Load planning
HVAC Load Calculator
Aggregate documented preliminary load components; this is not a Manual J or final equipment-selection result.
Preliminary load inputs
Enter documented component values. Zero is allowed only when a component is genuinely absent or included elsewhere.
How this calculation works
The tool sums user-supplied envelope, solar, people, lighting, equipment, and outdoor-air sensible components. Lighting and equipment watts are converted using 3.412141633 BTU/h per W. Outdoor-air sensible load uses 1.08 × CFM × delta T in US customary units.
Inputs and limits
Envelope and solar values must come from a documented method. Window area, orientation, insulation, exterior exposure, climate, infiltration, humidity, occupancy, schedules, and equipment can materially change the result. Latent loads, hourly heat storage, duct losses, and codes are not resolved here.
Result interpretation
The calculator reports preliminary cooling and heating BTU/h, nominal tons, thermal kW, and a sensible supply-air CFM estimate. Tonnage and thermal kW are conversions, not electrical input or equipment-selection instructions.
Use as a transparent planning worksheet
For a detailed residential load and equipment selection, use the appropriate recognized method and qualified review. Continue to the BTU to Tons Calculator, CFM Calculator, and Duct Size Calculator only after reviewing the load basis.
Frequently asked questions
Can I enter zero for a component?
Yes, only when the component is genuinely absent or already included in another documented input.
Does the CFM result set ventilation?
No. It is a sensible cooling airflow estimate based on your supply-air delta T. Ventilation must follow applicable project and code requirements.
Can this replace Manual J?
No. It is a preliminary component aggregator, not a full residential load procedure or equipment selection method.