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Should My AC Be on AUTO or ON?

It depends on your purpose. Many argue for both sides, and most of the time, they are all correct. 

However, many Hawaii homeowners don’t understand that both the ON and AUTO thermostat settings are useful for their intended purposes. 

In this article, we will identify the benefits and disadvantages of switching the thermostat to the ON and AUTO settings, so that you can decide which mode to use for your specific air conditioning needs. 

A digital thermostat on a wall

What is a Thermostat?

First, let’s understand what a thermostat is and how it works. 

A thermostat is your air conditioner’s remote control. It senses your room’s temperature and instructs your AC unit to adjust by cycling longer until it reaches your desired temperature and cycles off after that. 

It is a handy device that can curb your AC unit’s energy consumption as it provides cooling, comfort, and excellent indoor air quality. 

  • A programmable thermostat lets you schedule different temperature settings based on your needs. A smart version learns your schedule and activities and can adjust the room temperature based on energy efficiency. 
  • A manual thermostat typically has a digital display that shows your desired temperature, which you can set with a button’s push. It has limited features and needs to be manually switched on and off. 
  • An analog thermostat is the oldest type and uses a dial which you need to turn right or left to your desired temperature. 

What Does the Thermostat's AUTO Setting Do?

The thermostat’s ON and AUTO settings control the AC unit’s blower, which distributes and circulates the air inside your home. 

On AUTO mode, the fan turns on automatically when cooling or heating your air. It also turns off automatically upon reaching the desired temperature indicated in the thermostat. 

AUTO Setting Advantages

These are the benefits of setting your thermostat to AUTO mode: 

  • Energy Efficiency. You save more energy and reduce your energy bill because the AC unit isn’t at work all the time. Your air conditioner cycles off immediately once it reaches the desired room temperature. 
  • Fewer Air Filter Replacements. You don’t need to clean or replace your air filters as often because the air conditioner is not working 24/7. But you still need to clean them at least every two months to keep your AC unit working properly and save on energy.
  • Efficient Temperature Control. You have total control over the air conditioning system because all you have to do is set your desired temperature, and the AC unit will follow. For example, you can adjust the temperature to five degrees higher than the average if you want to save more energy. Once the AC reaches that temperature, the thermostat automatically tells the AC to cycle off. 
  • Better Dehumidification. Moisture from the cooling coils has enough time to drip and drain outside. 

AUTO Setting Disadvantages 

These are the reasons why you shouldn’t set you thermostat to AUTO mode: 

  • Hot and Cold Spots. The air distribution throughout the house may be uneven, leaving some areas colder than others. It’s because the fan is turned off once the thermostat senses that the desired temperature has been reached and stops distributing cold air. 
  • Limited Air Circulation. Since the AC unit cycles off once it reaches your desired temperature, the air does not circulate through the air conditioner until the next cycle. This leaves dust, particulates, contaminants, and moisture mixed in the air and not trapped in the air filters. 
  • Blower Fan Wear and Tear. Frequent start-and-stop cycles will eventually take a toll on the AC’s blower fan, especially without regular maintenance. 


What Does the Thermostat's ON Setting Do?

When your thermostat is on the ON setting, the AC unit’s blower fan continuously blows air even when the air conditioner is not heating or cooling the room. 

ON Setting Advantages 

Switching your thermostat to ON mode has these benefits: 

  • Equal Air Distribution. With the blower fan consistently at work, cold air is distributed to all areas of your home evenly. You don’t have to worry about the hot temperature in the basement and chilling temperature in the upstairs bedrooms since the fan balances out the air distribution. 
  • Improved Indoor Air Quality. As indoor air continuously circulates in the room, the air filters also consistently catch the air contaminants and particulates for improved indoor air quality. Clean indoor air is beneficial, especially for children, the elderly, or family members with asthma and allergies
  • Fewer Cycles. Not having to turn your AC unit on and off frequently can extend its years of serviceability since there is less stress on the blower fan. 

ON Setting Disadvantages 

These are the cons to programming your thermostat to ON mode: 

  • Higher Energy Bill. Expect higher energy consumption and utility bills because the AC is working non-stop.
  • Frequent Air Filter Replacement. Your air filters catch and trap contaminants and allergens more often because your AC is working all the time. To avoid clogged air filters and malfunctions, you need to clean and change the air filters more frequently than usual, at least once a month. 
  • Overworked Blower Fan. Without proper and regular maintenance, your air conditioner may experience blower fan malfunctions from working non-stop. 

Practical Thermostat Tips

Choosing between the ON and AUTO settings is a personal preference. Choose the ON setting if you have children, pets, and family members with asthma and allergies to ensure clean indoor air every time. 

Choose AUTO mode if you are keen on cutting down your monthly energy bill. 

You can alternate both options depending on the situation. Choose the ON mode when everyone is at home for maximum comfort. 

At night, you can switch to AUTO mode when the outside temperature is not too hot. You can also use the AUTO mode before leaving your home and when no one else is around. 

Also, follow these simple thermostat tips to enjoy comfort and convenience without high energy costs: 

  • Invest in a smart thermostat that automatically controls room temperature based on your preferences and activities. 
  • Raise the room temperature at night or when you are going out to save ten percent on energy use. 
  • Place your thermostat away from direct sunlight and heat-producing devices. This way, it won’t pick up the wrong temperature and overwork your AC unit. 

AC Maintenance with Island Comfort

Ensure that your thermostat and air conditioner are always working correctly and at their best to deliver comfort and excellent indoor air quality at a reasonable cost. 

Contact Island Comfort at (888) 781-0364 for fast and reliable AC installation, repair, and maintenance services.

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