How a Duct Blaster Detects Air Leaks in Ductwork

 

A duct leakage performance test entails pressurizing the duct system using a calibrated fan while concurrently monitoring airflow via the fan and its influence on duct pressure. The quantity of airflow required to sustain a given pressure difference is related to the degree of system leakage. You can compute the air exchange rate by knowing the volume of the space being tested and monitoring the airflow (ACH). The ACH is a measurement of how many times the air in a room is entirely replenished in an hour. If the ACH in a room is 4, for example, all of the air in that room will be replaced with fresh air four times in one hour. 

 

How does a duct blaster detect air leaks in the ductwork? Using a calibrated fan to pressurize the duct system, the challenge for most amateurs is converting this figure into an equivalent tightness or “Q” value that quantifies just how much air is moving through cracks and openings.  To do this, you need some knowledge about how houses are built and how they “leak” energy. Once you have this foundation, converting ACH50 values into Q values becomes easy. Here’s how it works:

 

First, every house has what’s called an envelope—walls, ceilings, doors, windows, and floors that separate the interior living space from the outdoors. The quality of construction and materials used to build this envelope determine how much heat escapes or enters through it. When we refer to a house as being “tight” or “leaky,” we’re really talking about how effective its envelope is at holding heat inside during cold weather and keeping it out during hot weather. 

 

The second key piece of information you need to know is that almost all homes have natural air leaks—cracks around window frames, gaps where plumbing or electrical wires enter or exit walls—that provide pathways for heat to escape or enter. These natural leaks are usually small, but they exist in every home regardless of age or condition. 

 

The challenge for most amateurs is converting this figure into an equivalent tightness or “Q” value that quantifies just how much air is moving through cracks and openings. To do this, you need some knowledge about how houses are built and how they “leak” energy. Once you have this foundation, converting ACH50 values into Q values becomes easy. Building an energy-efficient home starts with understanding how tightly sealed it needs to be—and that means learning how to convert an ACH50 number into a Q score.

 

We offer air duct and dryer vent cleaning services in the Greater Sudbury area. Call or text  today for a free estimate at 705-996-4553

 

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