There are times when your HVAC system just doesn’t seem to be doing enough. Connecting rooms may be receiving air unevenly, or the furthest rooms may not be getting enough air. Many contractors will suggest installing booster fans, but do they really work?
The short answer is, yes and no. Your mileage may vary based on several factors, so it is best to look at where these fans succeed and fail before making a final decision.
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Types of Booster Fans
There are two major classes of booster fans available on the market, each with their own specific uses. In a few extreme cases, you may wish to use a mix of both. However, most homes will only require one type of fan, and the decision may come down to personal preference.
Inline Booster Fans
Inline booster fans are located within the ducts themselves, activating as needed to help maintain airflow. They are best used for houses that have a large network of ducts. Quiet and efficient, inline fans are a cheaper alternative to replacing your duct system entirely.
While these fans range in price from $30 to $200, they also have added installation fees involved. An inline fan is designed to replace a section of ductwork and is often hard-wired into the furnace.
This means you will need an electrician and the section of duct must be exposed before installing. You will also need to choose an appropriate size for your ductwork.
Unlike inline fans, register fans are installed within each room and plug directly into the wall. This means much cheaper installation, although their power is more limited in larger buildings. Costing between $30 and $80, some more expensive models sport a digital thermostat, multiple speeds, and remote control functionality.
Where Booster Fans Work
Booster fans are useful for helping to pull air out of the ductwork and into a room. They won’t solve an airflow problem on their own, but may be a cost-effective means to circumvent to more expensive repairs.
Register Fans for Ducts in Older Homes
The ductwork in older houses was not designed to accommodate modern HVAC systems and thus often fail to provide even heating. Register fans are a cheap solution which helps to pull air into a room while the furnace is running.
Choosing a model with a built-in thermostat will further help for rooms which receive the least amount of airflow.
Inline Fans for Complicated Ductwork Layouts
Found most often in larger buildings, this problem is exactly as it sounds: The ducts are full of complicated bends and divisions which slow the flow of air from the furnace to the rooms. The further air has to travel, the less benefit your rooms will receive.
Inline booster fans may be installed at key points along the ductwork to help to keep air flowing at a higher speed. They help pull air past registers which previously vented out most of the hot or cool air into an adjoining room, allowing the air to flow further along the ducts.
Where Booster Fans Fail
Booster fans do what the name says – they boost airflow. Unfortunately, there are times when an underlying problem cannot be solved by simply adding a few fans.
In many cases, this comes down to the condition of your HVAC system, and adding a booster fan will have little or no effect until the underlying problem has been addressed.
Common HVAC Issues
Poor airflow is often a matter of improper maintenance and can be solved with little or no cost. One frequently overlooked reason is the air filter. Getting the wrong type of filter for your furnace or failing to replace it regularly can result in clogs that greatly reduce the efficiency of your furnace fans.
It is always a good idea to check the furnace filter once every few months and to keep at least one spare filter around for quicker replacement.
Another common issue found in older homes is peeling duct tape separation between sections of ductwork. In both cases, air is escaping from the ducts, reducing the overall pressure. A simple test with colored smoke will usually reveal leaks in the ducts, allowing for quick repairs.
Unfortunately, some leaks may require excavating a section of duct from a wall or ceiling in order to effect repairs.
Poor Air Returns
When your registers aren’t putting out a lot of air, it’s easy to forget about the air returns. These ducts pull air back out of a room and pipe it to the furnace. This is especially important on the upper floors of your home, where air must make its way down to your furnace’s location.
In many older homes, the air return system is inadequate for modern HVAC systems and may need to be expanded or even completely replaced.
Due to the fact that return air vents often lack fans or are situated in difficult to reach places, they are prone to debris buildup. Dust and dirt can slowly clog the system, as well as any objects which find their way inside.
Rodents, birds, and other pests have been known to build nests in these passageways, blocking the flow of air to your furnace and causing your furnace to work harder for a smaller result.
Regularly vacuuming the return vents and checking for debris will help keep them working smoothly and allow the entire ventilation system to work more effectively.