Air Changes Per Hour to Cubic Metres Per Hour Converter
Instantly convert your required air changes per hour (ACH) into the cubic metres per hour (m³/h) airflow you need, based on your room’s volume. Accurate, free, and easy to use.
Convert Your Airflow Rate
Enter your room’s dimensions (or volume directly) and the target air changes per hour to get an instant m³/h airflow figure — perfect for sizing extractor fans, MVHR units, and ventilation systems.
ACH to m³/h Converter
Fill in your room details to see the required airflow
Target ACH for this room type
Auto-fills a typical ACH value
Required Airflow
Converted from ACH to cubic metres per hour
Recommended ACH by Room Type
Typical recommended air changes per hour for common spaces, along with the resulting airflow for an average-sized room of that type.
| Room Type | Typical ACH | Avg. Volume (m³) | Approx. Airflow (m³/h) |
|---|---|---|---|
| Bedroom | 3–4 | 30 m³ | 90–120 m³/h |
| Living Room | 3–6 | 45 m³ | 135–270 m³/h |
| Kitchen | 6–10 | 35 m³ | 210–350 m³/h |
| Bathroom / En-suite | 8–15 | 10 m³ | 80–150 m³/h |
| Office | 4–8 | 60 m³ | 240–480 m³/h |
| Commercial Kitchen | 15–30 | 80 m³ | 1,200–2,400 m³/h |
| Plant Room / Workshop | 10–20 | 100 m³ | 1,000–2,000 m³/h |
| Laboratory | 15–30+ | 70 m³ | 1,050–2,100+ m³/h |
ACH to m³/h FAQ
Everything you need to know about converting air changes per hour into cubic metres per hour, and choosing the right ventilation rate.
Multiply the air changes per hour (ACH) by the room volume in cubic metres. The formula is m³/h = ACH × Room Volume (m³). For example, a 50 m³ room needing 6 ACH requires an airflow of 300 m³/h.
Recommended rates vary by space. Living rooms and bedrooms typically need 3 to 6 ACH, kitchens and bathrooms need 6 to 15 ACH due to moisture and odour, and commercial kitchens or plant rooms can require 15 to 30+ ACH.
Multiply the room’s length, width, and height, all measured in metres. If you only have measurements in feet, convert each to metres first by multiplying by 0.3048, then multiply the three figures together.
Extractor fans and ventilation units are rated in m³/h. Converting your required ACH into m³/h lets you match the room’s ventilation needs to a fan with sufficient airflow capacity, avoiding under-ventilation or an oversized, noisy, and wasteful unit.