R-Value, Wind, and Air flow Imperial to Metric Converter

R-Value, Wind Speed/Pressure and permeability rate values can get really confusing with imperial and metric versions, so we thought we would dedicate some easy to use calculators to help people make these calculations. Enjoy…

Enclosed are some Calculators that may be very handy to some, researching air-tightness of commercial and residential buildings around the world. Converting a permeability rate in the United States of America so that the rest of the world can understand it, and vice versa.

Fill in any value in each table, and the calculated equivalent will automatically be populated in above or below fields.

Calculation converting permeability rate CFM/ft² to m³/h/m²

cfm/ft²@50Pa:
m³/h/m²@50Pa:

Insulation R-Value Conversions, Imperial R-value is very very different to Metric R-values. If you come across any tables in the US, sharing R-value performance of materials, use this calculator to convert them to a more recognisable value.

Calculation converting R-value Metric to Imperial

US R Value:
Metric R Value:

Wind speed calculation with induced pressure calculation. This can be really helpful when understanding the average overall pressure that might be affecting a building in a particular area by using weather bureau data. Windspeed/Pressure (Pa) induced on building facades, on wind experienced on a day or via an average. ACH/Permeability rate @ an average induced pressure(pa) designated as ambient. Use this calculator to work out what the ambient pressure may be, using wind speed values.

Wind Effect Diagram