An option to resolve insufficient airflow

Whole home comfort requires getting conditioned air to where it is supposed to be

By Russell Jones


Do you ever feel frustrated by customers’ HVAC system’s inability to provide conditioned air to some of the rooms furthest away from the furnace? You are not alone. Insufficient airflow is one of the most common heating and cooling complaints made by clients and they look to us to fix the issue.

Many people are at a loss as to why their HVAC system is able to serve some rooms much better than others. While there are plenty of reasons for this, one explanation is a small or weak fan that is incapable of moving the right amount of air through the ductwork and out of the vents.

In cases such as these, an air duct booster fan may be a solution.


What is an air duct booster fan?

As the name implies, an air duct booster fan is basically a fan that can be attached to the ductwork in an HVAC system. Designed to increase the airflow to the more distant parts of a home, a booster fan will typically be installed in long sections of ductwork and then hooked up to an electricity supply.


How do they work?

Inline fans are designed to replace a section of regular ductwork. Inline and register are the two main types of booster fans. Inline fans are built to be installed inside the ductwork itself. Because they can shift large volumes of conditioned air, inline fans are often used in larger properties with extensive networks of ducts.

These fans look somewhat like a regular section of ductwork. They are designed to replace a section of regular ductwork, so it is essential to choose one with the same dimensions as the existing ducts. Once installed, these fans are cheap to run and do not use much in the way of electricity.

Instead of being installed as part of the ductwork itself, register booster fans are designed to replace the registers in rooms that are receiving low airflow. Register fans are cheaper and cost less to install. They also plug directly into the wall. Some of the better models have thermostats, variable speed options, and remote-control operation.

While register booster fans cost significantly less than the inline solution, the amount that is saved on a single unit will likely be offset when you have to install multiple fans in each room in which you need to increase air flow.


What are the advantages of duct booster fans?

Booster fans may not solve the airflow problems in an HVAC system on their own, but they can help increase air circulation in a number of ways.


1. Boosting older ductwork

Modern HVAC systems have revolutionized how we heat and cool our homes. However, merely installing a powerful new furnace or air conditioning system may not yield the results that it should if the customer lives in a home that has ductwork from another era.

Old ductwork did not use today’s airflow technology in its design and often fails to pull air through the system to supply all rooms of the house, evenly leaving warm or cold spots in the home.

In cases where you have old ductwork, it may be more cost-effective to install a duct booster or set of register fans to help move the air through the ductwork better.


2. Extra power for complex ductwork layout

Larger properties with many rooms or several floors often require complex ductwork systems to connect the whole indoor environment up to the HVAC system. A more extensive system of ductwork will mean that warm or cool air will be lost due to low airflow to rooms further away from the HVAC unit.

Booster fans can be an effective way of moving air past the many bends and divisions that usually feature in larger networks of ductwork to improve heating and cooling.

Inline booster fans can be placed strategically near sections with registers to help pull more of the air past them so more of it reaches underserviced rooms and areas.


3. Put off costly repairs

In some cases, booster fans can be used to effectively put a bandaid on an HVAC unit that is not working that well anyway. Some customers want booster fans or register fans installed to increase airflow to avoid paying money for repairs or a new HVAC unit that is capable of pushing through higher volumes of conditioned air.


When a duct booster fan will not work

There are several cases in which installing a duct booster fan will not provide the necessary solution. If the ductwork is old and has cracks and holes through which air is escaping, it is unlikely that simply pulling through more air is going to make much difference to the volume of airflow in hard-to-reach rooms of the home.

Similarly, if the furnace or AC unit is old and worn out so that it no longer produces sufficient conditioned air, increasing the airflow with a fan will have no effect.

Before installing a duct booster fan, you should first check that the other parts of the system are working correctly. Airflow problems may be caused by damaged or leaky ductwork, clogged filters, or a system component that needs replacing.