Printable worksheet

← Back to the Air Changes per Hour Calculator

In the print window, choose “Save as PDF” as the printer (or print it on paper). Seed 1 rebuilds this exact sheet.

Air Changes per Hour worksheet

Grades 6–7 · CCSS 6.RP.A.3.d, 6.G.A.2

Solve each problem and show your work. Round answers to 2 decimal places where needed.

1.
Problem 1.
- Solve for: Airflow needed
- Units: US (feet, CFM)
- Room length: 16 ft
- Room width: 11 ft
- Ceiling height: 7 ft
- Target air changes per hour: 5 ACH
Find: Airflow needed
Answer
2.
Problem 2.
- Solve for: Air changes per hour
- Units: Metric (meters, m³/h)
- Room length: 3 m
- Room width: 3 m
- Ceiling height: 3 m
- Airflow: 180 m³/h
Find: Air changes per hour
Answer
3.
Problem 3.
- Solve for: Air changes per hour
- Units: Metric (meters, m³/h)
- Room length: 3 m
- Room width: 3 m
- Ceiling height: 2 m
- Airflow: 180 m³/h
Find: Air changes per hour
Answer
4.
Problem 4.
- Solve for: Air changes per hour
- Units: Metric (meters, m³/h)
- Room length: 6 m
- Room width: 4 m
- Ceiling height: 3 m
- Airflow: 160 m³/h
Find: Air changes per hour
Answer
5.
Problem 5.
- Solve for: Airflow needed
- Units: US (feet, CFM)
- Room length: 12 ft
- Room width: 10 ft
- Ceiling height: 8 ft
- Target air changes per hour: 4 ACH
Find: Airflow needed
Answer
6.
Problem 6.
- Solve for: Air changes per hour
- Units: US (feet, CFM)
- Room length: 12 ft
- Room width: 7 ft
- Ceiling height: 7 ft
- Airflow: 90 CFM
Find: Air changes per hour
Answer
7.
Problem 7.
- Solve for: Airflow needed
- Units: Metric (meters, m³/h)
- Room length: 2 m
- Room width: 4 m
- Ceiling height: 3 m
- Target air changes per hour: 4 ACH
Find: Airflow needed
Answer
8.
Problem 8.
- Solve for: Airflow needed
- Units: US (feet, CFM)
- Room length: 15 ft
- Room width: 10 ft
- Ceiling height: 6 ft
- Target air changes per hour: 6 ACH
Find: Airflow needed
Answer
9.
Problem 9.
- Solve for: Air changes per hour
- Units: Metric (meters, m³/h)
- Room length: 3 m
- Room width: 3 m
- Ceiling height: 2.4 m
- Airflow: 155 m³/h
Find: Air changes per hour
Answer
10.
Problem 10.
- Solve for: Airflow needed
- Units: Metric (meters, m³/h)
- Room length: 3 m
- Room width: 3 m
- Ceiling height: 2.4 m
- Target air changes per hour: 5 ACH
Find: Airflow needed
Answer

Answer key: Air Changes per Hour worksheet

1. Airflow needed: 102.67 CFM
1. Find the room's volume (how much air it holds): length × width × height
  $16 \times 11 \times 7$ $= 1,232 ft³$
2. Multiply the target air changes by the room volume, then divide by 60, because CFM counts air per minute
  $\frac{5 \times 1,232}{60}$ $= 102.666667 CFM$
2. Air changes per hour: 6.67 ACH
1. Find the room's volume (how much air it holds): length × width × height
  $3 \times 3 \times 3$ $= 27 m³$
2. Divide the hourly airflow by the room volume to count how many roomfuls of air move each hour
  $\frac{180}{27}$ $= 6.666667 per hour$
3. Air changes per hour: 10 ACH
1. Find the room's volume (how much air it holds): length × width × height
  $3 \times 3 \times 2$ $= 18 m³$
2. Divide the hourly airflow by the room volume to count how many roomfuls of air move each hour
  $\frac{180}{18}$ $= 10 per hour$
4. Air changes per hour: 2.22 ACH
1. Find the room's volume (how much air it holds): length × width × height
  $6 \times 4 \times 3$ $= 72 m³$
2. Divide the hourly airflow by the room volume to count how many roomfuls of air move each hour
  $\frac{160}{72}$ $= 2.222222 per hour$
5. Airflow needed: 64 CFM
1. Find the room's volume (how much air it holds): length × width × height
  $12 \times 10 \times 8$ $= 960 ft³$
2. Multiply the target air changes by the room volume, then divide by 60, because CFM counts air per minute
  $\frac{4 \times 960}{60}$ $= 64 CFM$
6. Air changes per hour: 9.18 ACH
1. Find the room's volume (how much air it holds): length × width × height
  $12 \times 7 \times 7$ $= 588 ft³$
2. Multiply the airflow by 60 to get air per hour, then divide by the room volume to count roomfuls
  $\frac{90 \times 60}{588}$ $= 9.183673 per hour$
7. Airflow needed: 96 m³/h
1. Find the room's volume (how much air it holds): length × width × height
  $2 \times 4 \times 3$ $= 24 m³$
2. Multiply the target air changes by the room volume to get the airflow needed each hour
  $4 \times 24$ $= 96 m³/h$
8. Airflow needed: 90 CFM
1. Find the room's volume (how much air it holds): length × width × height
  $15 \times 10 \times 6$ $= 900 ft³$
2. Multiply the target air changes by the room volume, then divide by 60, because CFM counts air per minute
  $\frac{6 \times 900}{60}$ $= 90 CFM$
9. Air changes per hour: 7.18 ACH
1. Find the room's volume (how much air it holds): length × width × height
  $3 \times 3 \times 2.4$ $= 21.6 m³$
2. Divide the hourly airflow by the room volume to count how many roomfuls of air move each hour
  $\frac{155}{21.6}$ $= 7.175926 per hour$
10. Airflow needed: 108 m³/h
1. Find the room's volume (how much air it holds): length × width × height
  $3 \times 3 \times 2.4$ $= 21.6 m³$
2. Multiply the target air changes by the room volume to get the airflow needed each hour
  $5 \times 21.6$ $= 108 m³/h$