How to Choose the Right Size for An Air Purifier

How to Choose the Right Size for An Air Purifier


Air purifiers are great appliances for removing common pollutant particles from the air you breathe, in your home.

It will effectively remove dust, smoke, and pollen, alongside other pollutants, ensuring you and your family have a constant supply of fresh, healthy air.

Given that most modern air purifiers come in many sizes and with a vast array of features, here’s how to choose the right size for your home. 

How to Choose the Right Size for An Air Purifier

1. Determine Where to Install

When choosing the ideal air purifier size, the installation area should be the priority consideration. You need to first determine the most ideal spot to place it.

Determine whether you need an air purifier for one room, multiple rooms, of for the entire house. Obviously, given the variation in size across the three categories, then the air purifier sizes will also differ.

2. Establish the Square Footage of the Room

After deciding on the installation space, proceed to measure its size in square feet. Square footage is the standard for space sizing because most air purifiers are also rated in square feet.

Single Room

If you’re working with a single room, measuring it is quite easy. Simply grab a tape measure and get the dimensions of 2 perpendicular walls. You can then use these measurements to get the room’s area in square feet.

For example, a 20-foot by 15-foot room has a total area of 300 square feet.

Multiple Connected Rooms

In such cases, simply measure the length and with of each room, as you had done for the single room, then sum up the totals.

For example, assume you have 2 adjoining rooms; the first has an area of 150 square feet, while the second is 100 square feet in area. The total area for the entire space would be 250 square feet.

Whole House

If you’re sizing an air purifier that covers your entire house, then calculating the space’s total area accurately, could prove tedious, time-consuming, and inefficient.

To avoid all the complexities associated with measuring your entire house, try and retrieves the paperwork that came with your purchase of the home, or the house plan, in case you built the property. Such documents should indicate the total area of the house in square feet.

But if the paperwork is not available, you can still get the near-accurate square footage of your entire house by simply going outside and measuring the length and width of its external walls.

Whole House (Multi-Level)

If your home has multiple levels, multiply the area obtained from the lower level by the total number of levels. For example, 2-level home with an external square footage of 1,500 square feet has a total area of 3,000 square feet (1,500 x 2).

3. Match the Square Feet Rating on the Air Purifier to Your Room

Choose an Air Purifier Slightly Larger than the Room Area

As a best practice, get a purifier rated to clean a larger space than the one you’ll be using it in. Aim for a purifier whose capacity is at least 1/3 larger than that space.

For example, if you have a total area of 600 square feet, then choose a purifier rated for 800 square feet, for superior cleaning efficiency.  

The best way to shop for a whole-house purifier is to get multiple appliances that service smaller spaces. For instance, if you have a 3-level home and each level has an area of 1,200 square feet, you can get 3 purifiers, each with a rating of 1,500 square feet.

For apartments, matching the appliance to room size is relatively easy. Typically, apartments have standard sizes in square footage, so you may end up needing to purifier a smaller space, which may prove affordable compared to doing the same in a large home.

Quick Estimation using CADR Rating

You can also determine the right air purifier size by using the clean air delivery rate (CADR), a standard rating used to measure the particle removal capacity of purifier (in cubic feet/minute).

The Environmental Protection Agency (EPA) recommends getting an air purifier whose CADR is high enough to cover the size of the room you want to clean.

Most air purifier models will indicate the largest area the appliance can be used in, and here’s a handy guide by the EPA to helps simplify purifier sizing:

Right Size for An Air Purifier



An air purifier is, without a doubt, an invaluable appliance to have in your home. It will improve the overall quality of air and help prevent allergies.

But choosing the right size of air purifier can prove intimidating. You can simplify this process by identifying where the appliance will be used and installed, then accurately sizing the installation area in square feet.

Then, simply match the room size and purifier rating to get the most ideal model for your space and air purification needs.


  1. Choosing the Right Air Purifier – US Air Purifiers