design
Natural Ventilation Opening Calculator
Estimate minimum openable window area as a percentage of room floor area.
Target openable area
2 m²
Floor area
20 m²
Opening target
10%
How this works
Target openable area = floor area × selected ventilation percentage.
Worked example
A 20 m² room using a 10% target needs about 2 m² of openable area.
FAQ
What is the Natural Ventilation Opening Calculator used for?
Estimate minimum openable window area as a percentage of room floor area. It is intended for quick planning, checking, and everyday decisions.
Can I use the result for a final contract or design?
Use it as a planning estimate. Local code, room use, cross-ventilation, obstructions, climate, and mechanical systems may require more.
How can I improve the accuracy?
Use measured quantities, current supplier or lender rates, the correct units, and compare the result with drawings, invoices, or professional advice where the decision is safety-critical.