What is air change? - Air change is the movement of a volume of air in a given period of time.If a house has one air change per hour, it means that the air in the house will be replaced in a one-hour period.
Ventilation Calculator
* indicates minimum
The actual amount of air changed in a well-mixed ventilation scenario will average around 63.2% after 1 hour and 1 air change per hour (ACH).
The higher the value the better the ventilation.
In simple terms, change the CFM (Cubic Feet per Minute) into Cubic Feet per Hour(CFH). Then calculate the volume of the room by multiplying the room height times the width times the length. Then simply divide the CFH by the volume of the room.
For a more extensive overview and to give you a better understanding, here’s a table of the average air changes depending on the room;
| Room Type | Air Changes |
|---|---|
| All spaces in general | min 4 |
| Assembly halls | 4 - 6 |
| Attic spaces for cooling | 12 - 15 |
| Public Auditoriums | 8 - 15 |
| Bakeries | 20 - 30 |
| Banks/Building Societies | 4 - 8 |
| Barber Shops | 6 - 10 |
| Bars | 20 - 30 |
| Bathrooms | 6 - 10 |
| Beauty Shops | 6 - 10 |
| Bedrooms | 5 - 6 |
| Pool Halls | 6 - 8 |
| Boiler Rooms | 15 - 30 |
| Bowling Alleys | 10 - 15 |
| Cafeterias | 12 - 15 |
| Canteens | 8 - 12 |
| Basement | 3 - 10 |
| Changing Rooms Main area | 6 - 10 |
| Changing Rooms Shower area | 15 - 20 |
| Churches | 8 - 15 |
| Cinemas and theatres * | 10 - 15 |
| Classrooms | 6 - 20 |
| Clubhouses | 20 - 30 |
| Cocktail Lounges | 20 - 30 |
| Compressor rooms | 10 - 20 |
| Computer Rooms | 15 - 20 |
| Conference rooms | 8 - 12 |
| Copy Room | 10 - 12 |
| Court Houses | 4 - 10 |
| Dairies | 8 - 10 |
| Dance halls | 12 minimum |
| Dental surgeries | 12 - 15 |
| Large Shops | 6 - 10 |
| Dining Halls | 12 -15 |
| Restaurant Dining Area | 12 |
| Dress Shops | 6 - 10 |
| Chemists | 6 - 10 |
| Dye works | 20 - 30 |
| Electroplating shops | 10 - 12 |
| Engine rooms | 15 - 30 |
| Factories and workshops | 8 - 10 |
| Factory buildings, with fumes or moisture | 10 - 15 |
| Fire Stations | 4 - 10 |
| Food Staging Area | 10 - 12 |
| Foyer - public buildings | 15 - 20 |
| Metal Workshop | 15 - 20 |
| Galvanizing plants | 20 - 30 |
| Garages | 6 - 8 |
| Garages repair | 20 - 30 |
| Garages storage | 4 - 6 |
| Greenhouses | 25 - 60 |
| Gymnasiums | 6 minimum |
| Hairdressing salons | 10 - 15 |
| Homes, night cooling | 10 - 18 |
| Hospital rooms | 4 - 6 |
| Hospitals - sterilising | 15 - 25 |
| Hospitals - wards | 6 - 8 |
| Jewelry shops | 6 - 10 |
| Kitchens - commercial | 30 minimum |
| Kitchens - domestic | 15 - 20 |
| Laboratories | 6 - 15 |
| Laundrettes | 10 - 15 |
| Laundry Room | 8 - 10 |
| Lavatories | 6 - 15 |
| Lecture theatres | 5 - 8 |
| Libraries | 3 - 5 |
| Living rooms | 6 - 8 |
| Lunch Rooms | 12 -15 |
| Machine shops | 6 - 12 |
| Malls | 6 - 10 |
| Medical Offices | 8 - 12 |
| Mills, paper | 15 - 20 |
| Mills, textile dye houses | 15 - 20 |
| Mills, textile general buildings | 4 minimum |
| Municipal Buildings | 4 - 10 |
| Museums | 12 -15 |
| Mushroom houses | 6 - 10 |
| Nightclubs | 20 - 30 |
| Offices | 6 - 10 |
| Offices, private | 4 minimum |
| Offices, public | 3 minimum |
| Paint shops (not cellulose) | 10 - 20 |
| Photo & X-ray darkrooms | 10 - 15 |
| Pump rooms | 5 minimum |
| Recording control rooms | 15 - 25 |
| Recording studios | 10 - 12 |
| Homes | 1 - 2 |
| Restaurants | 8 - 12 |
| Retail Outlets | 6 - 10 |
| School Classrooms | 4 - 12 |
| Shoe Shops | 6 - 10 |
| Shopping Centers | 6 - 10 |
| Shops and supermarkets | 8 - 15 |
| Shops, machine | 5 minimum |
| Shops, paint | 15 - 20 |
| Shops, woodworking | 5 minimum |
| Shower baths | 15 - 20 |
| Smoking Room | 13 - 15 |
| Squash courts | 4 minimum |
| Stores & warehouses | 3 - 6 |
| Substation, electric | 5 - 10 |
| Supermarkets | 4 - 10 |
| Swimming pools | 20 - 30 |
| Taverns | 20 - 30 |
| Theaters | 8 - 15 |
| Toilets 6 - 10 | 6 - 10 |
| Town Halls | 4 - 10 |
| Transformer rooms | 10 - 30 |
| Turbine rooms, electric | 5 - 10 |
| Utility rooms | 15 - 20 |
| Waiting rooms - public buildings | 4 minimum |
| Warehouses | 6 - 30 |
| Welding shops | 15 - 30 |
*The information has been put together as a guide. Where air changes are critical you should consult and confirm air changes and extract performance of your proposed products with an engineer and/or a manufacturer of the ventilation product*