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

Have you ever felt that you’ve stepped into the sandy beaches of the Sahara from a refreshingly cool beach as you moved from one corner of your house to another? If yes, you need to start your HVAC fan to get rid of the difference in temperature.

The heating, ventilating, and air conditioning system is with a fan you can control via your thermostat. HVAC blower fans are used to circulate air through an area and remove hot and cold areas until the temperature you set by your thermostat is reached.

They operate in two modes, Auto and On, and there is always this huge debate over which is the best. However, both these modes have their advantages and drawbacks, and there isn’t a definitive answer on whether you should keep your AC fan running on auto or. Furthermore, the latest intelligent thermostats allow you to customize fan settings!

HVAC Fan Modes – Auto & On

HVAC fans allow for ventilation and improve indoor air quality and improve the comfort of your home. Let’s explore the intricacies of the Auto and On modes and how each operates, and which you should select.

What’s the Meaning of the ‘On’ Mode?

The “On” mode indicates that your HVAC fan will be running throughout the day. This setting implies the HVAC system’s fan will always be running even when your AC isn’t in use.

There are benefits and downsides to running an HVAC fan on a continuous basis.

Advantages of using the “On feature

1. Improved Air Circulation

When your air conditioner heats or cools the air, it’s not able to circulate the air properly by itself. A fan spreads the conditioned air better around your home and assists in removing any hot and cold spots.

Another issue related to air circulation is that hot air rises up, whereas cold air lies near the ground. This could cause heat to gather in the upper stories of your home, increasing the temperature here. Therefore, keeping your AC fan in operation all the time will help circulate the air on the upper floors all the time and not just when cooling is turned on.

2. Increased Life Time

In keeping an AC fan on means it won’t have to start and then stop repeatedly as it reduces the strain generated by the fan. You may be surprised, but this technique can increase the life of your HVAC blower.

3. Fresh Odorless Air

Temperature levels stay moderate during spring and fall, especially in enclosed spaces and buildings with windows mostly shut. In this situation there is a chance that the air conditioner will be turned off, resulting in the air becoming stuffy. It is important to keep your HVAC fan on will help you keep the air fresh and clear any odors.

4. Improved Air Quality:

Maintaining an AC fan running every day means that air passes through the AC filters more frequently. This can help remove pollutants in the air, such as dust, pollen, bacteria, and mold.

The benefit that you can get from air filtration will depend on the type of air filters installed on your HVAC unit and how well they are maintained. Filters with a high MERV rating can effectively remove most of the tiny particles in the air.

Pros and Cons of the ‘On feature

Below are some disadvantages of making use of this “On” mode of your HVAC unit.

1. High Energy Bills

Keeping your air handler fan always on will certainly add up to the energy bill. Based on the model, size, and length for which of time an AC is in operation it can consume around 500 Watts or more while running an HVAC fan. This can accumulate to 360 kWh per month.

2. It is often necessary to change the Air Filter

In a room, when air constantly circulates by HVAC air filtering, they become filled with dirt faster. It is essential to wash the air filter more often or change them more frequently. 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 located near the attic or near walls can be filled with hot air in summer. The air circulates through your home because the fan is constantly running. The result is that your room ends up getting hot, and the air conditioner turns on more frequently in order to reduce the room temperature.

4. Cold Air in Winter

If you turn on the fan of your air conditioner during winter while the heating is off, you will feel a cold breeze coming out of your vents. Although the air temperature remains the same, you experience a cold sensation.

5. Inefficient Humidity Removal

Moisture is removed from the air when it is cooled. The air flows over the Evaporator coils and then moisture forms on the coils in the form of droplets. When the system ceases cooling the coils heat up and water droplets drip down. This water should be expelled from your home.

However, running the HVAC fan indefinitely causes some of the water to evaporate and re-enter the air, which causes an obstruction to the depletion of moisture.

What is meant by Auto Mode?

Setting the HVAC system fan to “Auto” is a way of running it only when it is cooling or heating. In other words, once your thermostat is at the appropriate temperature, the system turns off, including the AC’s fan.

Pros of Using an HVAC Fan’s Auto Function

1. More Energy Efficiency

Running your AC fan on the Auto setting indicates that it will only be running while the system is either heating or cooling. So, the fan runs for the shortest amount of time possible. Therefore, it is more energy efficient to turn your fan to Auto instead of continuously operating the fan. This means you will pay less energy.

2. Better Dehumidification

Since the HVAC fan shuts off in Auto mode after cooling ceases, droplets of moisture on condensation coils can easily drop to the pan underneath the coils. Then, the moisture is efficiently disposed of outside the home. This helps you achieve an ideal level of humidity in your home.

Pros and Cons of using the ‘Auto’ Feature

While this option provides better humidity control and saves money, there are a few factors that can cause issues for you.

1. Uneven Temperature

A lack of circulation once the system shuts down means hot air will continue to increase, and cold air will remain in the lower area of the room, which can cause an uneven temperature.

2. More Rapid Wear Out

Setting your HVAC blower in Auto mode will cause the fan motor to switch on and off repeatedly. This will cause the motor to wear out quickly and shorten its life.

Verdict to AC Fan Mode”On” or ‘Auto’?

There is no definite answer to questions such as “how long will my HVAC fan be running per hour?” or “Should my fan be running on “Auto” or “On “?”.

Running the fan frequently or setting the AC fans to “On” instead of “Auto” is a personal choice as both these options have advantages and disadvantages. 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.

But the only thing to consider is the level of humidity in the region you reside in. If you live in a location that has high levels of humidity setting the HVAC fan on “On” can result in poor humidity removal and could cause the growth of mold. In these conditions, running your AC fan on “Auto” is safe.

Certain options may aid in eliminating the negatives while making use of all the advantages!

  • Smart Thermostat With smart thermostats, you can also set up custom timers to run your fans only at the required settings. You can set the duration of your AC fan will run every hour irrespective of the heating or cooling cycles.
  • Variable Speed Technology: Implementing variable-speed technology for fan motors in your HVAC is another option. A variable-speed fan motor operates at various speeds to regulate the flow of air in your home in the most efficient way.

Through variable speed technologies, the AC fan is continuously running to move air around, however, because it has the ability to run at lower capacity the system is more energy efficient. It means that your power bills will not increase due to the AC fan, and your system won’t have to be turned on and off repeatedly. This system thus provides better humidity control, a long time of life for the fan motor, consistent temperature, and continuous filtration.

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