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Calcimator

Air Purifier Sizing Calculator

CADR needed from room size and air changes per hour.

Inputs

Results

Recommended CADR (cfm)

120

ACH-based CADR (cfm)96
Room volume (ft³)1,440
Floor area (ft²)180
Units needed (250 CADR each)1
Annual filter cost ($)$80.00
Annual energy (kWh)438
How to Use This Calculator
  1. Enter Room length (ft), Room width (ft), and Ceiling height (ft).
  2. Set Target air changes/hour.
  3. Review the Recommended CADR (cfm) result.
  4. Use ACH-based CADR (cfm) and Room volume (ft³) to inform your decision.

How the result changes with Room length (ft)

Room length (ft)Recommended CADR (cfm)
21168
71568
1301,040
1801,440

What each input means

Room length (ft)
Length of the room in feet.
Room width (ft)
Width of the room in feet.
Ceiling height (ft)
Floor-to-ceiling height. Standard residential is 8 ft.
Target air changes/hour
Desired air changes per hour. 2–4 general, 4–6 allergy, 6–12 medical.

What each result means

Recommended CADR (cfm)
Minimum Clean Air Delivery Rate needed, accounting for AHAM 2/3 rule.
ACH-based CADR (cfm)
CADR calculated from room volume and target air changes per hour.
Room volume (ft³)
Total room volume in cubic feet.
Floor area (ft²)
Room floor area in square feet.
Units needed (250 CADR each)
Number of typical 250-CADR purifiers required.
Annual filter cost ($)
Estimated yearly cost for replacement filters.
Annual energy (kWh)
Estimated annual electricity usage running 24/7.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Room length (ft) = 15, Room width (ft) = 12, Ceiling height (ft) = 8, Target air changes/hour = 4 = 4 input(s) provided
  2. Calculate Recommended CADR
    Recommended CADR = max(requiredCADR, ahamMinCADR)
    120 = 120
  3. Calculate ACH-based CADR
    ACH-based CADR = (roomVolumeFt3 * targetACH) / 60
    96 = 96
  4. Calculate Room volume
    Room volume = roomLength * roomWidth * ceilingHeight
    1440 = 1440

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