Cooling & Airflow

Air-conditioner sizing in BTU and tons, ventilation rates and duct sizes.

• BTU Calculator — Air Conditioner Sizing Works out the cooling capacity a room needs in BTU, tons and kW, and the nearest air-conditioner size to buy.
• CFM Calculator — Airflow and Air Changes Airflow in CFM, m³/h and L/s — from room volume and air changes per hour, or from cooling capacity.
• Duct Size Calculator Round duct diameter and the rectangular equivalents for a given airflow and air velocity.