What is this hub?
An HVAC calculator hub groups tools for BTU estimates, cooling tons, furnace size, CFM, duct dimensions, and load planning.
Calculator hub
HVAC Calculators.
HVAC calculators help estimate heating and cooling loads, airflow, duct sizing, equipment tonnage, and furnace capacity.
Why use these tools?
HVAC sizing depends on room size, insulation, climate, windows, airflow, equipment efficiency, and comfort targets. Calculators provide early planning numbers before formal design.
How to choose
Use BTU or HVAC load tools for room load estimates, tonnage to convert BTU and AC capacity, furnace size for heating, CFM for airflow, and duct size for air distribution.
Available calculators
Choose a hvac tool
HVAC Load Calculator
Estimate heating and cooling load in BTU per hour from room size, climate, insulation, air tightness, windows, and internal heat factors.
Open calculatorFurnace Size Calculator
Estimate heating BTU and suggested furnace size using area, climate, insulation, and efficiency.
Open calculatorBTU Calculator
Estimate room cooling BTU per hour using room size, climate, insulation, sun exposure, occupants, and windows.
Open calculatorTonnage Calculator
Convert BTU per hour to cooling tons, convert tons to BTU, or estimate AC tonnage from area and room conditions.
Open calculatorCFM Calculator
Calculate airflow in CFM from room volume and air changes or from duct size and air velocity.
Open calculatorDuct Size Calculator
Size round or rectangular HVAC ducts from airflow and target velocity, or check velocity in an existing duct.
Open calculator
Common questions
Are HVAC calculators the same as a Manual J load calculation?
No. They are planning estimators. Final HVAC equipment sizing should use the appropriate professional load calculation method and local design conditions.
What does CFM mean?
CFM means cubic feet per minute. It measures airflow and is commonly used for ventilation, duct sizing, and HVAC distribution planning.