Decoding Air Purifier Specs: A 5-Minute Guide to Room Size & CADR

At a Glance:

With rising air pollution and worsening Air Quality Index (AQI) levels, especially across India’s metro cities, the demand for air purifiers has surged. But not every purifier works for every space. The effectiveness of it largely depends on choosing the right air purifier room size and ensuring that every corner of your space actually gets the clean air you’re paying for. Let’s see how to get that match just right.

As per the Economic Times, “A report from Markets & Data suggests the Indian air purifier market is projected to witness a CAGR of 12.23 per cent during FY2026-FY2033, growing from USD 151.52 million to USD 381.37 million. This is particularly due to increasing air pollution, rapid urbanisation, and greater health awareness.

We all know what air purifiers are and how they work, but many of us still struggle to pick the right one. Should we prioritize an air purifier as per room size or should brand be the preference? Let’s find out.

CADR, ACH, and Room Size: How Do They Affect the Air Purifier’s Performance

When buying an air purifier, it’s easy to get lost in technical terms like CADR, ACH, and room size. But understanding these three factors is key to knowing how efficiently your purifier will clean the air. Let’s learn about these terms in detail.

Pre-owned Electronic Home Appliances

AHAM, which stands for Association of Home Appliance Manufacturers, is a U.S.-based organization that tests and certifies home appliances, including air purifiers to ensure they meet consistent performance and safety standards. 

When it comes to air purifiers, AHAM plays a major role through its AHAM Verifide® certification program. It does independent testing to test air purifiers in controlled lab environments to measure how effectively they remove pollutants like dust, smoke, and pollen. Let’s talk about the various technical terms it uses to test and certify air purifier performance:

CADR (Clean Air Delivery Rate)

So, AHAM (Association of Home Appliance Manufacturers) has a metric system called CADR that reflects the ability of air purifiers to remove different types of particles from the air. With the help of CADR, you can easily assess the air purifier’s efficiency in removing particles like dust, pollen, and smoke from the air. 

It’s usually expressed in cubic meters per hour (m³/hr). A higher CADR means the purifier can remove pollutants like dust, smoke, and pollen faster, ideal for larger rooms or spaces with heavier pollution.

ACH (Air Changes Per Hour)

The ACH indicates how many times the air purifier can replace the air in the entire room within an hour. For example, an ACH of 4 means the purifier cleans all the air in the room four times every hour. A high ACH indicates that the air is being filtered more frequently. This becomes especially important during peak infection seasons or for individuals prone to allergies and asthma.

HEPA Filters

There’s a big difference between HEPA and HEPA-like filters. A True HEPA filter (High-Efficiency Particulate Air) traps 99.97% of tiny particles like dust, pollen, and smoke, making it highly effective for cleaner, healthier air—especially for people with allergies or breathing issues.

Air Purifiers – Room Size

Every air purifier is designed to cover a specific room size. Using a purifier meant for smaller areas in a large room will reduce its effectiveness, no matter how advanced it is. Matching your device to the correct air purifier room size ensures optimal performance and energy efficiency. 

Start with the coverage area that you are expecting. You can calculate the area of the room by multiplying the length and the breadth of the room. Always check the air purifier’s square footage rating to ensure it matches your room size.

The AHAM also provides recommended room sizes based on CADR results, helping buyers match an air purifier to their space accurately.

Step-by-Step Guide to Buying the Best Air Purifier for Your Room Size

With a pool of options available in the market, finding the right air purifier for the room size can be overwhelming. If you’re unsure where to start, we’ve got you covered! 

Here is a step-by-step guide to get the perfect air purifier for your room size and home.

Step1: Start by measuring your air purifier room size in square feet, because without knowing the exact area, you can’t choose an air purifier that’s truly suited to your space. But how do you do it? Just multiply the length and width of your room.

Step 2: The next step is to pick a model that has a CADR that goes with your room size. For example, CADR for medium-sized rooms should be between 200 and 300 CFM.

If someone in your home has ongoing breathing issues or allergies, or if you’re a pet owner, aim for an air purifier with at least 4–5 ACH. ACH basically tells you it’s cleaning count in one hour.

Step 3: Choose the filter type you want. There are HEPA and Ozone Air Purifiers or activated carbon filters that help neutralize odors and smoke. For added protection, consider models with UV, ionizer, or plasma filters that target bacteria and airborne germs.

Step 4: Once done, look for the model’s air purifier coverage area mentioned in the specifications.This tells you the maximum room size the device can handle effectively. Always ensure the purifier’s coverage slightly exceeds your room size for the best results.

Air Purifier Room Size: Suggested Models

Here are some recommended models based on air purifier room size and budget. 

If you’re on a tight budget, consider exploring used or second-hand air purifiers on OLX. It’s a smart way to give your loved ones the clean, healthy air they deserve — without burning a hole in your pocket.

Bottom Line: Should you be buying an Air Purifier?

There was a time when we used to look at the weather widget on our phones to check if it was going to rain or if it would be sunny. But today, with rising air pollution levels, most of us also keep an eye on the Air Quality Index (AQI), not just for where we live, but for the places we plan to visit. This growing awareness has made air purifiers an essential home appliance rather than a luxury. After all, who doesn’t want to breathe clean, fresh air every day? 

This guide will help you choose the right air purifier room size. It’s important to consider factors like CADR, ACH, and coverage area before finalising your purchase. 

You can also explore OLX to buy second-hand air purifiers for your home, without compromising on quality or stretching your budget!

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