Setting the fan speed too low will usually cause the evaporator coil to freeze. If the fan speed is too high, it can cause the AC condenser to short-cycle or turn on and off constantly. This puts a huge amount of stress on the unit and also results in greatly increased energy costs.
For your AC system to cool efficiently, the fan needs to be able to move a certain amount of air every minute. For every AC ton, you need between 350 to 400 cubic feet of air per minute (CFM), i.e. a 2.5-ton AC needs 875 to 1,000 CFM, a 5-ton AC needs 1,750 to 2,000 CFM, etc.
So, according to the US government, running the fan speed on high is the best course of action except on very humid days (but no explanation why). They also say that running on a low fan speed on humid days will both cool your home more effectively and remove more moisture.
Does fan speed affect electricity consumption? Yes, the fan motor consumes less electricity at a slower speed. Inserted resistance reduces the voltage available to the fan motor.
Keeping your fan on AUTO is the most energy-efficient option. The fan only runs when the system is on and not continuously. There is better dehumidification in your home during the summer months. When your fan is set to AUTO, moisture from cold cooling coils can drip and be drained outside.
Cons to Keeping Fan Continuously Running:
It could cost you hundreds of dollars a year. The average unit has a 500 watt fan, which uses almost as much energy over the course of the year as a refrigerator, resulting in a $50/month bill.
You might think a taller fan or a fan on an elevated surface is your best bet to cool a room, as it attacks that higher-up hot air, but as Lasko points out, a fan situated lower to the ground can actually pick up the “refreshing chilliness” lingering down there and push it out.
As mandated by the Ministry of Power, Government of India, all AC manufacturers must fix the default temperature setting at 24°C. So, it is better to set the right temperature at about 24-25 degrees Celsius. This will help in cooling the room faster.
"AUTO" is the more energy-efficient option, as it runs the fan only when heating or cooling is actively needed. "ON" keeps the fan running continuously, which can help with air circulation and filtration but may consume more energy.
A good RPM for a ceiling fan is between 200-300 RPM, as it provides a comfortable breeze without generating excessive noise or consuming too much power. However, the ideal RPM may vary depending on factors such as the fan size, room size, and ceiling height.
Fans don't wear down as fast as people claim -- they're rated to run at 100% for tens of thousands of hours.
HVAC experts will tell you all the same thing: turning your thermostat to a lower setting DOES NOT cool your home faster. Setting your thermostat to 65 degrees will not get your home cooler faster than setting it at 73.
The general rule is that the blower fan needs to circulate between 350 and 400 cubic feet of air per minute for each AC ton. A 3-ton AC requires 1,050 to 1,200 CFM, a 4-ton unit needs 1,400 to 1,600 CFM, etc. The speed of the blower fan determines how much air volume the system moves.
Setting your thermostat to auto will allow your system to be more energy-efficient since the fan only runs when the system cycles on, not continuously.
AUTO is significantly more energy efficient between the two modes since the fan is only running when your AC is going through its cooling cycle. This takes less power, which is more budget-friendly, with some estimates showing you can save as much as $50 per month just by keeping your AC on AUTO.
What is the Best Thermostat Setting for Summer Air Conditioner Use? Energy Star recommends the following thermostat temperatures for your air conditioner in the summer: 78°F during the day if people are home. 82°F at night if people are home.
While the standard room temperature of 72 degrees Fahrenheit is commonly favored by many, others argue for higher settings, particularly when it's hotter outside.
WHAT IS THE BEST MODE FOR AC IN SUMMER? In summer, the best mode for your air conditioner is the "Cool" mode, set to a comfortable temperature around 78°F when you're home. This setting efficiently reduces indoor humidity and maintains a comfortable environment without overworking the AC system.
Most AC systems are set to operate at 400 cubic feet per minute (CFM) at installation. However, for homes that are airtight or prone to humidity issues, a lower fan speed of around 350 CFM may work better.
Eco or energy-saving mode
This is the ideal mode for users looking to save up on energy bills by toning down the performance of the AC and its compressor. Eco-mode uses less electricity by automatically adjusting the fan speed and temperature, while still maintaining a comfortable level of cooling.
Reduced Strain on the System
By setting a slightly higher temperature, you reduce the strain on your AC unit. This can prolong its lifespan and prevent unnecessary repairs, ultimately saving you money in the long run.
The fan will constantly blow air into your room if you have the thermostat turned “ON.” If it is on “AUTO,” it will only turn the fan on when heated air needs distribution. So yes, running HVAC continuously throughout the day and night is perfectly safe!
Using your ceiling fans and AC unit simultaneously can help save you money on your monthly cooling bill. According to the Department of Energy, if you use air conditioning to cool your home, a ceiling fan will allow you to raise the thermostat setting about 4°F with no reduction in comfort.
Consequences of Running Your Air Conditioner 24 Hours a Day
Wasted energy: Running the AC to cool your home beyond your comfort level wastes energy and contributes to an increased carbon footprint. This is bad news for the environment and your energy bills.