Posted on: December 26, 2022 Posted by: itappsoft Comments: 0

Have you ever felt that you’ve stepped onto the sandy beaches of the Sahara from a cool and breezy beach while moving from one corner of your house to the other? If you answered yes, then you must start your HVAC fan in operation to stop this temperature discrepancy.

HVAC, Ventilation, and air conditioning system is with a fan you control using your thermostat. HVAC blower fans are used to circulate air in rooms and eliminate hot and cold areas until the temperature you set by your thermostat is reached.

These fans have two working modes: Auto and On, and there is always a debate about which one works best. But both methods have their advantages and drawbacks, and there isn’t an exact answer to which one you should use. AC fan On or Auto. Additionally, the most recent intelligent thermostats are also able to set custom fan settings!

HVAC Fan Modes – Auto & On

HVAC fans allow for ventilation and aid in maintaining indoor air quality and improve the comfort of your home. Let’s dig into the details of the Auto and On modes, how each of them functions, and which you should select.

What exactly is meant by the “On” Mode?

The “On” mode indicates that your HVAC fan will run all day long. This implies that your HVAC system’s fan will always work even when the AC isn’t in use. 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 running an HVAC fan on a continuous basis.

Advantages of using the “On’ Feature

1. Improved Air Circulation

While your air conditioner is heating or cooling the air, it’s not able to circulate air effectively by itself. A fan distributes the conditioned air further around your home and also helps eliminate cold and hot spots.

Another issue with air circulation is that hot air rises up while cold air is near the ground. This causes hot air to accumulate in the upper stories of your home, raising the temperature. Thus it is important to keep your AC fan always on will efficiently circulate air on higher floors throughout the day not just when your cooling is running.

2. Increased Life The Span

Keeping an AC fan running means it won’t be required to start and then stop repeatedly, which will reduce stress on the fan. Believe it or not, this technique can increase the life that your HVAC blower.

3. Fresh Odorless Air

Temperatures remain mild during the fall and spring, particularly in sealed buildings and spaces with windows mostly shut. In such a situation there is a chance that the air conditioner will be turned off, resulting in the air becoming stuffy. The ability to leave your HVAC fan running can aid in keeping the air clean and remove any odors.

4. Improved Air Quality:

If you have an AC fan running continuously means that the air goes by all of your AC filters more often. This can help remove indoor airborne contaminants like dust, pollen, bacteria, and mold.

However, the benefit you reap from air filtration will depend on the type of air filters fitted in your HVAC system and how well they are well-maintained. Filters that have a high rating are capable of effectively removing the majority of the small particles that are in the air.

The Cons of using the ‘On feature

Listed below are some downsides of choosing”On,” the “On” mode of your HVAC unit.

1. High Energy Bills

Keeping your air handler fan on all the time will surely rack up your energy bills. Based on the type, size, and length of time an AC has been used, an air conditioner can consume around 500 Watts or more when running an HVAC fan only. This could add up to 360 kWh per month.

2. The need to frequently change the Air Filter

When air from a room is continuously circulated through HVAC air filters the filters become blocked faster. It is necessary to clean your 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 placed near the attic or in close proximity to walls can get filled with hot air in summer. The air circulates through your house when the fan is constantly running. In the end, your room ends up getting hot and the AC turns on more frequently to bring down the room temperature.

4. Cold Air in Winter

When you switch on the air conditioner’s fan in winter, while the heating is off, you will experience a chilling breeze flowing through your vents. Although the temperature of the air is the same, you still get a cold feeling.

5. Inefficient Humidity Removal

Moisture is removed from the air as it cools. Air flows through coils for evaporation and moisture accumulates on the coils in the form of droplets. When the system stops cooling, the coils warm up and droplets of water pour down. The water must be drained out of your home.

However, running the HVAC fan on a continuous basis causes some of the water to evaporate back into the air, thus causing a hindrance to the effective elimination of the humidity.

What is the meaning behind the Auto Mode?

Set the HVAC unit fan on “Auto” is a way of running it only when it is heating or cooling. For instance, when your thermostat has reached the desired temperature, the system switches off, including the AC’s fan.

The advantages of using an HVAC Fan’s ‘Auto’ feature

1. More energy Efficiency

The AC fan running on the Auto setting means that it is only running while the system is heating or cooling. So, the fan runs for the minimum period possible. This makes it more energy efficient to turn your fan on Auto than continuously running the fan. As a result, you will pay less energy.

2. Better Dehumidification

Since the HVAC fan shuts down in auto mode when cooling ceases, water droplets on condensation coils can easily drip down into the drain pan located underneath the coils. Thereafter, moisture gets effectively removed from the house. This ensures that you have an ideal level of humidity in your home.

Cons of Using the ‘Auto’ Feature

Although this mode can provide greater humidity control and can save money, there are a few factors that might cause a problem for you.

1. Uneven Temperature

The lack of circulation after the system shuts down will mean that hot air will continue to rise, and cold air will stay within the lower parts of the room, leading to an uneven temperature.

2. Speedier Wear Out

Setting your HVAC blower in Auto mode can cause the fan motor to turn on and off frequently. This causes the fan motor to wear out quickly and shorten its life.

A verdict regarding AC Fan Mode: ‘On’ or “Auto”?

There’s no clear answer to questions like “how long should my HVAC fan run per hour?” or “Should my fan be turned on “Auto” or “On “?”.

In the event of frequent use, setting your AC fans to “On” instead of “Auto” is an individual choice since both of the modes have their 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.

But the only thing that is important here is the level of humidity of the region you reside in. If you live in an zone where humidity levels are high, setting your HVAC air conditioner to “On” could result in inefficient humidity removal and cause the growth of mold. In these areas, running the AC fan at “Auto” is safe.

However, certain options could assist you in removing the drawbacks while making the most of the advantages!

  • Smart Thermostat: By using smart thermostats you can also create custom timers to run your fans only at the settings you require. You can choose how long your AC fan runs every hour regardless of the cooling or heating cycles.
  • Variable Speed Technology The incorporation of variable-speed motor technology to your HVAC is another option. Variable-speed fan motors operate at various speeds to regulate the airflow of your home in the most efficient way.

By using variable-speed technology This AC fan runs continuously to move air around, but since your system has the ability to run at lower speeds the system is more energy efficient. That means your energy costs won’t be skyrocketing because of your AC fan and your system will not have to shut off and turn on frequently. This makes it easier to achieve more control over humidity, long fan motor life, even temperaturecontrol, and continuous filtration.


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