Here we have two types of calculators to calculate the required CADR from air purifiers for your room:

- CADR Calculator using universal formula (dynamic and versatile)
- Tobacco Smoke CADR Calculator using AHAM’s Formula (limited usage)

### CADR Calcualtor (universal formula):

You can easily calculate the **required CADR** (universal formula) using:

- Room area
*(square footage or L x W),* - Ceiling height, and
- Your preferred air exchange rate (ACH) per hour.

Calculate the required CADR from the calculator below:

**CADR in CFM**= (ACH x Room Area x Ceiling Height) / 60

2. **CADR in m3h** = CADR in CFM x 1.699

### What is CADR?

CADR or Clean Air Delivery Rate represents an air purifier’s **filtering efficiency**. It Indicates the air purifier’s filtration rate at a specific time. CADR is expressed in CFM (cubic feet per minute) or m³/h (cubic meter per hour).

For example, an air purifier with a labeled CADR 200 CFM means, it delivers 200 cubic feet of filtered air every minute on its highest fan speed settings.

The term **‘Clean’** means **‘filtered air,’** and it doesn’t guarantee filtration quality. CADR is more likely a quantitative measure than a qualitative standard.

Filtration quality depends on filter types, grades, and other factors. For example, a True HEPA-grade filter can filter out 99.97% of 0.3 micron-sized particles.

### How Important is the CADR?

The CADR rating is the key metric for evaluating an air purifier based on **efficiency**. Also, you have to consider the other aspects such as filter types, filter surface area, effective air intake-outlet design, etc.

In a nutshell,

*Air Purifier Efficiency = CADR ratings*

*Air Purifier Effectiveness = Filter types*

### Tobacco Smoke CADR Calculator:

You can easily calculate the required Tobacco Smoke CADR (AHAM’s Formula) using:

- Your Room area
*(square footage or L x W)*.

*Ceiling height is always constant at 8 feet.

**Tobacco Smoke CADR**= Room Area / 1.55

AHAM’s CADRs Certificate Sample:

**AHAM’s CADR**

AHAM (Association of Home Appliance Manufacturers) certifies air purifiers with three different CADR ratings: **Tobacco Smoke**, **Dust**, and **Pollen**. Tobacco smoke CADR represents the efficiency against ultrafine particles, Dust CADR for fine particles, and the Pollen CADR is for coarse particles.

Here, you can find the list of AHAM-certified air purifiers with room size recommendations.

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