What is ACH?

Put simply, air changes per hour (ACH) is the measure of the outside air volume added to a space divided by the volume of that space over a set amount of time.    The air in your home is exchanged without an air cleaner, but at a much slower pace. You can increase your home’s ACH by simply turning on a fan, your HVAC system or increasing ventilation by opening a window. However, these methods don’t necessarily remove allergens and pollutants, and may even bring outdoor pollutants into your home.

Why is ACH important?

Modern homes are built to minimize energy losses and maximize energy efficiency. While this is great for your electricity bill, it reduces the rate at which allergens and pollutants are removed from your home. The Environmental Protection Agency estimates indoor air pollutant levels are two to five times higher than outdoor pollutant levels.   High levels of pollutants and allergens can create asthmatic and allergic reactions. We spend up to 90 percent of our time indoors, and having clean indoor air to breathe is essential.

Proper air changes may remove these particulates from the room.   The higher the number of air changes the more particulate removal. However, a portable air cleaner may be needed to provide additional air changed with cleaner air. Using an AHAM Verifide air cleaner helps make the air you and your family breathe cleaner.

Why do AHAM Verifide air cleaners base suggested room size on 4.8 ACH?

IAQ researchers have found that the minimum ventilation recommendation is three ACH, and the more ventilation or air changes you can achieve in a room further enhances the indoor air quality.  This means higher ACH values correspond to better ventilation. AHAM Verifide®  air cleaners are tested by an independent laboratory to ensure that they provide 4.8 ACH for their suggested room size, exceeding the minimum recommendation by nearly two full ACH.

What do I need to know when I am buying an air cleaner?

When buying an air cleaner, the most important thing to know is the size of the room you’ll be using it in. Calculating room size is easy – simply multiply the length of the room by its width. With that information, the AHAM Verifide® Directory will return a list of air cleaners certified to provide you with 4.8 ACH.

If you’re shopping for an air cleaner in person, you’ll find the AHAM Verifide® seal on the box of our certified air cleaners. The suggested room size is listed on the seal.

AHAM Verification Programs have been an important part of AHAM services since the Association’s inception. The programs provide a uniform and practical verification of energy, volume and certain performance criteria for each product, with an independent laboratory performing the verification testing. AHAM is recognized by the EPA as an Administrative Body and approved to administer verification testing for purposes of the ENERGY STAR program. Products may be selected at any time for verification testing, ensuring the product’s energy consumption and performance ratings consistent with manufacturer claims.  Since 1967, we’ve used outside labs to test products, and today, manufacturers use AHAM ratings on a variety of appliances.