Free Online HVAC Calculators – Heating, Cooling, Duct & Energy Tools

Quick, accurate HVAC calculators for load sizing, BTU estimates, duct design, airflow, and SEER energy savings.

Easily calculate heating and cooling loads, duct sizes, airflow requirements, and energy efficiency with our free HVAC calculator tools. Whether you’re planning a new system, upgrading equipment, or checking energy savings, our calculators help homeowners, contractors, and HVAC professionals make smarter decisions.

HVACR Calculators List

Heat Pump & AC

Core tools for residential/light-commercial AC & heat pump workflows.

SEER / Energy Savings Calculator Live

Estimate energy use & savings when upgrading system efficiency.

Duct Sizing & Airflow

Manual D helpers, fittings loss, balancing tools.

Duct Sizing & Airflow (Manual D) Live

Size ducts, estimate airflow, friction rate, velocity & equivalent length.

HVAC Load & System Sizing

Room-by-room loads, block loads, selection workflows.

HVAC System Sizing Calculator Live

Quick load-based capacity estimate to guide equipment selection.

Energy & SEER Savings

Payback, incentives, lifecycle cost calculators.

Coming Soon

Ventilation & IAQ

ACH, CO₂, filtration & fresh air sizing tools.

Coming Soon

Refrigeration (Superheat & Subcool)

Targets, charge optimization, refrigerant data.

Coming Soon