Should I Set my HVAC System’s Fan Setting to Auto or On?

A heating and cooling system is a great way to add convenience and comfort to your home, but often there are a number of settings that control these systems. Some common settings are fan speed, setback timer, thermostat temperature setting, etc.

We will discuss the fan settings and why you might want to choose “Auto” or “On”. Also, we will cover the pros and cons of each setting.

STOCK PHOTO: A man adjusts the temperature on a thermostat. (iStock)

What Is The HVAC Fan Setting?

The first thing that we need to discuss is what this setting actually is. This can be confusing because the term “fan” is used in a couple of different ways when referring to your heating and air conditioning unit. To make things easier, you can think of the fan setting as the actual fan unit or blower in your HVAC system. The fan is different from the blower and ducts. The fan unit is the part that actually blows air around your HVAC system. Therefore, the fan setting is where you set your actual fan.

The fan settings that you have on your air conditioning system are either Auto or On. For most people, this will probably be their only two settings. However, if you have a more advanced HVAC system, you might have other options as well.

The main difference is that when you set your fan to Auto, you let the HVAC system decide what to do with the fan. The HVAC system will decide if the air conditioner needs to use it or not.

On the other hand, when your HVAC system is set to On, it will always run at full power. This means that if your setting is On, your HVAC system will always blow air out at full speed no matter what position your temperature controls are in.

What is a Good Fan Setting?

A good fan setting on your HVAC system will allow you to stay comfortable in your home. The biggest issue that you might want to consider is the air conditioning system. Many homes have a condenser (and coils) for the A/C unit and an evaporator for the heat pump unit. These units require a lot of energy to run. One way that you can conserve energy is to have a fan setting that will turn on when needed or auto. This can save you a lot of money on your energy bill each month. Some models have a manual override that will allow you to run these units for a short period of time.

The other reason to set the fan setting to Auto is to save money on repairs. When the fan setting is set only on On, it means that the heat pump will run full blast all of the time, running your heating and cooling bills up. This can easily cause damage to your system and will be costly for you to remedy this problem. If your fan setting is set on Auto, it will only run when needed, saving you a lot of money every month.

When Should You Use the Auto Setting?

The first reason to set your fan setting to auto is an energy-saving tip. This setting allows your HVAC system’s blower motor to turn on when needed rather than always running. This can be a great way to save on your cooling bill, especially during the summer when you do not need the air conditioning running. This is also very useful in warmer winter months when you may only need your furnace to keep the heat at a comfortable temperature. The auto setting allows you to use less energy when you may not need it. This can greatly reduce the amount of energy your HVAC system uses.

Another reason that you should consider using the “Auto” setting is for maintenance. This will save you on repairs and service calls because it helps prevent damage to your HVAC system from running with the fan at full power. Many companies will not even honor a warranty if there is damage from improper use or maintenance. So, if you want to be sure that your warranty still applies, use your fan setting properly.

What is a Bad Fan Setting?

There are some drawbacks to having your HVAC system set to on. The biggest issue is safety. If the system is set to always be on, there is no way for the air handlers to turn off automatically. This can be dangerous if you have carpeting or wooden floors in your home. The other big issue is moisture. When the HVAC system is always running, this can lead to higher humidity levels in your home that can lead to mold, mildew and other types of mold. This can be a serious problem for people who have allergies or asthma and may find themselves in need of an inhaler more often.

The last drawback to having the system always running is that your HVAC unit will not be able to turn off when it is not in use. This can lead to higher energy bills each month if you would rather have the system running constantly. This would be similar to leaving your oven on without using it all the time. This setting can also put strain on your HVAC system, especially if it is a more advanced system that uses electronic controls. The electronics can easily be damaged by constant heating and cooling of the system.

Why you might want to set your fan setting to on?

The next thing that we will discuss is why you might want to have your fan setting to “On” rather than auto. This is generally a more expensive option as there are many costs involved with having the system running or not running. One of these costs is the energy that is used by the fans in your HVAC system. Some homes will have heating and cooling systems that are included in their monthly utility bill. This means that you will have to pay your utility company to operate your system. Therefore, if you can avoid running your HVAC system, this will save you money.

Other reasons to set your fan setting to on are that some homeowners just like the look of a clean home. Having a dusty living room or kitchen might be unpleasant for some homeowners. This is especially true for people who like to entertain or even have friends over for dinner and drinks. A dirty home can make it difficult to host guests and hard to enjoy yourself.

Setting your HVAC fan setting to on is one way to keep your home clean and inviting.


The auto fan setting is a convenient option for homeowners who are looking for a way to save money on their energy bills each month. This might be the best option for homeowners who struggle with allergies, asthma, or other chronic illnesses that can be made worse by high levels of moisture. However, this setting is not recommended for people who want to keep their homes clean. There are many things to consider before selecting a specific fan setting. We recommend that you have a professional HVAC technician in Los Angeles, CA check out your home’s HVAC system. There are many options for homeowners who want an efficient and energy-saving A/C system.

At Spectrum Heating and Air Conditioning Inc., we provide the best HVAC solutions for our customers. We pride ourselves on excellent customer service. In addition, we offer affordable air conditioning, heating, and other services to meet all of your needs. Our staff is here to help you with any of your heating or cooling needs, call us today!

Author: Victor G

Victor is an accomplished HVAC specialist who brings unparalleled comfort to your spaces. With a mastery of technical intricacies, he excels in curating ideal indoor environments. Besides his professional endeavors, Victor is a devoted family man, often creating cherished moments with his son and loved ones. When not fine-tuning heating and cooling systems, you can find him embracing outdoor adventures, diverse hobbies, and the simple joys of life. You can connect with him on Instagram 

Leave a Reply