All-in-One HVAC Load & System Performance Calculator

Quickly estimate cooling/heating loads, system size, and key performance metrics. Use Simple mode for fast estimates or Advanced mode for detailed analysis.

Load & Performance Calculator

Results are approximations. Always confirm with Manual J/D and OEM guidelines.

How This Calculator Helps

This tool combines cooling & heating load estimation with system performance checks to guide sizing and efficiency decisions. While it simplifies Manual J and performance calcs, it provides a fast starting point for homeowners and technicians.

Interpreting Results

  • Cooling Load: Total BTU/hr needed to maintain indoor setpoint.
  • Heating Load: BTU/hr required to heat in winter conditions.
  • System Size: Recommended capacity in tons (1 ton = 12,000 BTU/hr).
  • Efficiency (EER/SEER2): Higher = lower operating cost per BTU.
  • Capacity Utilization: Compares actual sensible load vs equipment capacity.

FAQ

What is a Manual J calculation?

Manual J is the ACCA standard for residential load calculations, considering walls, windows, insulation, infiltration, and more for precise sizing.

Why does ΔT matter?

The temperature difference between supply and return shows how well the system removes heat; typical ΔT is 16–22°F for cooling.

What is SHR?

Sensible Heat Ratio = sensible capacity ÷ total capacity. High SHR means more sensible cooling vs latent (humidity) removal.

How accurate is this tool?

It provides quick estimates. Always confirm final sizing with a full Manual J/D/S and manufacturer specs.