HVAC Fan: Should You Keep It Running on Auto or On?

Have you ever felt as if you’ve stepped onto the sandy beaches of the Sahara from a cool, breezy beach as you moved from one end of your home to the next? If yes, then you must start your HVAC fan in operation to stop the temperature difference.

The heating, ventilating, and air conditioning systems with a fan that can be controlled by your thermostat. HVAC blower fans are utilized to circulate air throughout the room, and to remove hot and cold areas until the temperature you set by your thermostat is reached.

They operate in two modes: Auto and On. There is always a debate over which is the best. Both methods have advantages and drawbacks, and there is no definitive answer as to which one you should use. AC fan on or in Auto. Additionally, the most recent intelligent thermostats allow you to customize fan settings!

HVAC Fan Modes – Auto & On

HVAC fans are used to provide ventilation and aid in maintaining indoor air quality and improving the comfort of your home. Let’s look into the specifics of the Auto and On modes and how each operates, and which you should select.

What is the meaning behind the “On” Mode?

“On” mode indicates that the HVAC fan will continue to run all day long. This means the HVAC system’s fan will always operate even when the AC isn’t cooling or heating. If your heating system has stopped working suddenly, you can contact San Francisco AC Repair Techs for Air Conditioning and Heating Repair in San Francisco to get it back to functioning.

There are some advantages and disadvantages of operating an HVAC fan on a continuous basis.

Benefits of using the ‘On!’ Feature

1. Improved Air Circulation

When your air conditioner is heating or cooling the air it is unable to circulate the air effectively by itself. A fan circulates the air conditioning more evenly around your home and can help eliminate any cold and hot areas.

Another issue with air circulation is that hot air rises up while cold air is near the ground. This causes the hot air to build up on the upper floors of your house, thereby raising the temperature. Therefore making sure that your AC is running continuously can help to circulate air over the higher floors throughout the day and not only when the cooling is running.

2. Increased Life The Span

Maintaining an AC fan running means that it doesn’t need to start and stop repeatedly and stop, which reduces stress on the fan. It’s true, this method can extend the lifespan of your HVAC blower.

3. Fresh Odorless Air

The temperature stays moderate throughout the months of spring and autumn, particularly in enclosed spaces and buildings that have windows that are mostly shut. In this situation the air conditioner could be turned off, resulting in the air becoming stale. The ability to leave your HVAC fan running can aid in keeping the air clean and remove any smells.

4. Improved Air Quality:

Maintaining an AC fan running continuously means that air is passing across the AC filters more often. This helps to remove pollutants in the air, such as dust, pollen, bacteria, and mold.

The benefit you get from air filtration is contingent upon the kind of air filters that are installed within your heating system as well as how well they are up to date. Filters that have a high MERV rating are able to effectively eliminate the majority of the small particles that are in the air.

The Cons of using the ‘On!’ Feature

Below are a few disadvantages of making use of this “On” mode of your HVAC fan.

1. High Energy Bills

The fact that your air handler is always on is sure to increase your energy costs. Based on the model, size, and length of time an AC is in operation the air conditioner could use around 500 Watts or more when operating an HVAC fan only. It can be as high as 360 kWh each month.

2. The need to frequently change the Air Filter

If the air in a room is continuously circulated via HVAC air filtering, they become blocked faster. It is necessary to wash the air filter frequently or change them regularly. If you have not thought about filter replacement for a while, don’t put it off any longer. AC Repair Techs AC Filter Replacement San Francisco is always ready to serve your needs.

3. Hot air in summer

Ducts that are installed in an attic or near walls could fill with hot air in the summer months. The air circulates in your home when the fan is running continuously. In the end, your home will become hot and the AC is on more often to lower the temperature of your room.

4. Cold Air in Winter

If you turn on the fan in your air conditioner in the winter months, even though the heating is turned off, you’ll notice a cold breeze emanating from your vents. While the temperature of the air remains the same, you will feel cold.

5. Inefficient Humidity Removal

Moisture is removed from the air when it is cooled. The air flows over the coils of evaporation, and the moisture is condensed on the coils in the form of droplets. When the system ceases cooling the coils heat up and droplets of water drip down. The water must be drained from your home.

However, operating the HVAC fan for a long period of time causes a portion of the water to evaporate back into air, causing an obstacle to the efficient elimination of the humidity.

What is the meaning behind Auto Mode?

Setting the HVAC fans to “Auto” is a way of running it only when it is cooling or heating. For instance, when your thermostat has reached the desired temperature, your system will turn off, including the AC fan.

Benefits of using an HVAC Fan’s Auto feature

1. More Energy Efficiency

The AC fan running on the Auto setting means that it will only operate only when the system is heating or cooling. Thus, the fan will run for the shortest amount of time possible. This makes it more efficient to set the fan to Auto rather than constantly operating the fan. In the end, you pay less for energy.

2. Better Dehumidification

Because the HVAC fan is shut off in auto mode when cooling ceases, the droplets of water on the condensation coils are able to fall to the pan located underneath the coils. Then, the moisture is efficiently disposed of outside the home. This will help you maintain optimal humidity levels inside your home.

Pros and Cons of using the ‘Auto feature

While this option provides greater humidity control and can save money, there are a few factors that could cause problems for you.

1. Uneven Temperature

Insufficient circulation after the system is shut down means the temperature will continue to rise, while cold air will remain in the lower portion of the room, which can cause an uneven temperature.

2. Faster Wear Out

Setting your HVAC blower in Auto mode can cause the motor of your fan to turn on and off often. This can cause the motor of the fan to wear out quickly and reduce its lifespan.

The verdict about AC Fan Mode”On” or “Auto”?

There isn’t a definitive answer to questions such as “how much time do I need to let my HVAC fan be running per hour?” or “Should my fan be set to “Auto” or “On “?”.

The fan is frequently running or changing the AC fan on “On” and “Auto” is an individual choice since both of these options have advantages and drawbacks. If your HVAC is not working and you are looking for an HVAC repair contractor in San Francisco, CA to get your commercial, industrial, or Residential HVAC System Repaired, San Francisco AC Repair Techs is the best choice to opt for. Every one of our technicians is licensed, qualified, and receives regular training to stay up-to-date with the latest developments in the industry.

The only thing that is important here is the level of humidity in the region you reside in. If you reside in a region that has high levels of humidity Setting the HVAC fan on “On” could result in inadequate humidity removal and lead to the growth of mold. In these areas, running the AC fan at “Auto” is safe.

But, there are some choices that can assist you in removing the drawbacks while making the most of the benefits!

  • Smart Thermostat: With smart thermostats, you can also set up custom timers that run your fan only when it is set to. You can decide how long your AC fan will be running every hour, regardless of cooling or heating cycles.
  • Variable Speed Technology: Integrating variable speed fan motors in your HVAC is an additional option. Variable-speed fan motors operate at various speeds, allowing you to regulate the airflow of your home in the most efficient way.

Using variable-speed technology The AC fan is continuously running to move air around, however, because it can run at lower capacity it’s energy efficient. This means that your electricity bills will not be soaring due to the AC fan, and your system won’t need to be turned on and off frequently. This will result in greater humidity control, a longer time of life for the fan motor, consistent temperatures, and continuous filtration. 



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