Residential Services: Air Balancing Chicago

Need Air Balancing in the Chicago Area?

The term “Residential Air Flow Test and Balance” in Chicago is often called, referred to, or nick-named “air balancing”. If you have ever been told that you r system needs to be balanced, this is the kind of testing you need.

The term “air balancing” simply refers to testing the amount of air flow from an area or part of the system and comparing it to what is actually supposed to be supplied to the room via a process called a load calculation (otherwise known as a “Manual J”).


Occasionally, different parts of the country call this many different things, but in Chicago, it is usually referred to air balancing. The process involves a set of architectural plans, typically the “M” Plans (otherwise known as Mechanical Plans). It is through these mechanical plans that we derive our “Manual J” A.K.A. “Load Calculation”.

This is how the actual size of your heating and air conditioning system is calculated. They take the plans, and, by looking at and detailing the construction materials used, they come up with something called a “load”, or simply, “load calculation”, or “Manual J”.

From there, when the size of the heating and air conditioning units are know, you can design a duct system, and come up with something called a “Ventilation Schedule”.

It is from this ventilation schedule that we use the data created to come up with the air flow that you need for your system, and to particular areas of the home.

When someone says you need your system balanced, or need air balancing, they are referring to a process in Chicago we call test and balance., otherwise known as air testing, or air balancing.

This process of air balancing uses specially calibrated air measurement devices to determine or calculate how much air is coming out of your ducts in a particular part of the system.

There are many “rules of thumb” to follow, but no matter how you slice it, the amount of air that is supposed to come out of your ducts is specifically designed via the method(s) described in brief above. So what does that mean to you? …

In Chicago, we perform air balancing as a means to test and certify or “prove” that the air that is supposed to come out of your systems / ducts is exactly, or within a certain tolerance, of what it was designed to provide.

So … In the Chicago Area and the surrounding suburbs, when you are told to have your system balanced, or that you require air flow testing and balancing, or that you need air balancing, all of these phrases mean the same thing … you are to have your duct system tested to ensure that it meets the air balancing criteria as set forth in the Chicago Code, the IMC (International Mechanical Code) or the IECC (International Energy Conservation Code).

Depending on where you are in the country, your air flow requirements will be different, as opposed to the air flow / air balancing requirements in Chicago.

WHY – Because, depending on the design temperatures outside, and the construction materials used, even the direction the room or that part of the house faces, can have a significant impact on your air flow requirements to that room or area.

BOTTOM LINE: Air Flow Testing, Air Balancing, and Air Flow Requirements are different in other parts of the country compared to those air balancing requirements in Chicago.


If you have hot or cold rooms, depending on the season, you need to have your air flow tested, balanced, and certified to prove that what was designed, is what is actually coming out of the supply vents or registers in your home.

Look at the diagram to the right:

Any one of these conditions can adversely affect your overall thermal comfort, temperature balance throughout the home, and throw off your air balance in the entire home.

Having zones that are our of balance can cause drafts in the home, as well as dust and airborne contaminant infiltration via the windows and doors and any part of the house that is unsealed or allows air or vapor barriers to be breached.

Air Balancing helps solve this problem by equalizing the temperatures and pressures in the home that otherwise go un-noticed.

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