We all wouldn’t mind saving a little energy. Residents are always seeking ways to use energy more efficiently with the intent of saving money on utilities and minimize their carbon footprint. But along the way, certain ideas have emerged about how people think they ought to use their air conditioner, versus how the air conditioner actually works. Here we examine and dispel five commonly held AC myths many users fall susceptible to so that you know the truth about your home’s heating and cooling!

Contrary to popular belief, air conditioners do not create, let in, or generate fresh air. Air conditioners are essentially appliances that refrigerate the air within a room.

Here’s a quick rundown on the inner workings of a conventional home AC unit: Air conditioners are equipped a special chemical compound called refrigerant, contained within a closed system of coils. Your AC forces this chemical compound to evaporate and condense into a gas within the system of coils. As this liquid compound converts into a gas, it becomes colder. The refrigerants convert from liquid back to gas in a continuous cycle through a compressor. Meanwhile, a fan located within the AC unit moves warm air from your room over the coils filled with cold refrigerant to chill the once warm air. This process of conversion generates heat, which is pushed outdoors by another set of condenser coils and a fan. While air conditioning may feel like new or fresh air is being produced in your room, in reality you are merely feeling refrigerated indoor air.

If that was confusing, this diagram might help:

The important thing to remember is that ACs do not generate new or fresh air as much as they refrigerate air that is already in the room or vehicle. If you want truly fresh air, look into placing screens over your windows so that you can open your windows at night when the air is cool. This will circulate daytime heat out of your home while preventing bugs from coming in.

With the exception of inverter ACs, conventional AC units can only turn the compressor ‘on’ or ‘off’. So whether you set your AC for 23C or 19C, your AC will not work any faster to reach one temperature over the other. A lower set temperature on your AC will eventually use more energy than a higher set temperature – and if you forget to re-adjust it, your AC will cool too much and run far less efficiently than it ought to. The smaller the difference between outdoor and indoor temperatures, the lower your overall cooling bill will be.

If you want to conserve energy, try using a fan. Fans can be very effective in air circulation and ushering warm air out of the room. Instead of solely relying on your AC to provide circulation, turn on your floor fan or ceiling fan and use them direct warm air to your AC. The air motion over our skin helps to evaporate sweat and transport our body heat away from us, which can make us feel several degrees cooler.

With the aid of a fan you can raise your AC temperature by a few degrees and re-distribute cool air throughout your home. If you have blinds on your windows, close them during the day to block out sunlight and place houseplants in front of sunny windows. The plants will effectively absorb the sun’s energy which will increase the efficiency of your ACs and fans.

Air conditioners consume energy at a rate that is based on outdoor temperature and relative humidity. However, the way AC remotes are designed often cause us to fixate on the temperature and “Power” buttons alone when using other AC modes can be more effective in achieving an ideal indoor climate.

While indoors, sometimes it is more beneficial to turn the temperature of our AC up while engaging the “Dry Mode” – the AC function that is more energy efficient at extracting humidity from the room. Humans are very sensitive to humidity and respond to moisture-heavy environments by sweating. This enables us to maintain a comfortable body temperature.

However as the air gets more humid, it becomes harder for our sweat to evaporate, even below 100% relative humidity. Because of our bodies are produce more sweat when it is humid, we often feel much hotter than the actual temperature.

Using the “Dry Mode” will cause the fan in your AC to operate at a slower speed, resulting in a cooler evaporator coil that condenses water vapor as the AC blows out the dry air through the appliance. This mode won’t completely dehumidify your home but it will reduce moisture and it also uses less energy than the full “Power” or “Cool” mode.

As long as your AC turns on and circulates cool air within your home, it may be easy to forget that these appliances need routine maintenance. But even if your AC appears to be running smoothly, it’s important to remember that your cold air machine may need a good clean to run as efficiently as possible. The difference between a dirty filter and a clean one can be up to ~5% so make sure to not skip on regular maintenance checks!

Some users believe that it is more effective to leave your AC running all day at one temperature than to turn it on at the end of the day. Your AC consumes less power or energy when completely turned off, as opposed to operating all day – even at a higher temperature. So in reality, it is more efficient to turn your AC off when it is not needed, or when no one is home. It also runs more efficiently when it is operating at full speed for shorter periods of time than when it is maintaining a constant temperature all day.

Insulation is one of the most effective ways to improve your home’s efficiency. Installing insulated windows will seal your home from heat and humidity in summer months while keeping it warm in colder weather during winter months. Alternatively, investing in heavy drapes is another cost-effective and less laborious method of insulating your home.

We want to know: do you have other AC myths you’d like to address? How do you resourcefully deal with the heat? Let us know.



    1. Hi Ian,

      While using economy mode will result in energy/money saving, since essentially it reduces your AC’s output power – it might mean the room will often feel slightly warmer. So, if you’re not a person that normally feels very hot, this might be a great way for you to save money!


  1. Your “Myth” #5 is answered incorrectly and #5 is not a myth but a fact. Especially with central ac units with temperature control settings. Providing that you’re referring to efficiently controlling and maintaining the comfort and temperature of the building. Which is what I would take as the intended meaning of #5. So stating that it is a myth because if you hook up a ac unit to a power source and turn it on it uses more energy than disconnecting it from power is a no brainer and no one anywhere needs that explained.


  2. I was just given a portable ac unit that has cool and dry mode. I do not live in a very humid climate. Does dry mode actually cool the room down? My instruction manual says if I use in dry mode I shouldn’t install the exhaust hose to the window. If I use in cool mode does it also dehumidify? In cool mode do I need to worry about the drainage hose and water coming out of it?

    Thank you.


  3. Does turning an AirCon to a low temp on a Low setting use more electricity as opposed to a med temp on a low setting? (Air Con has 3 settings low,med, high with temp setting)


    1. Hi Peter,
      Sorry to have missed your comment! A lower temperature used continuously over-time will use up more energy – using the same temperature without any adjustment to consider the room’s conditions is the reason; the AC works hard to cool. using a slightly higher temperature, as well as smartly adjusting the AC to match the environment and optimize it, will eventually lead to energy savings.


  4. Thanks for helping me understand more about air conditioning units. I appreciate that this article mentions that ti’s still important to do maintenance checks on an AC system, and to clean it every now and them to make sure it’s running efficiently. Definitely sounds worthwhile to learn more about the different ways someone can clean their unit, and how periodically they should do so.


    1. Hi Taylor,

      We’re glad you found this post useful and educational – that’s our aim! AC cleaning methods is definitely something worth talking about, and we might whip up a short post about it. Thanks for the idea! Regarding how often you should clean your AC filters, around every 6 months, and maybe more often if your home is very dusty or when the AC is on for longer (such as summer).


  5. Great article. I have a question – I live in Europe, where winter often brings a big problem – condensation. I have the rather good heating system (gas boiler with 5 radiators), but because of PVC windows lot of humidity stays in the apartment. I have found that my air condition (inverter, Panasonic CS-E12CKP) can do a great job reducing the humidity when set in dry mode. Question – how can I calculate the power consumption of my AC? Note that there is no use in opening windows since outside air is often more humid than inside.


    1. Hi Maja,
      Unfortunately the traditional AC makes it hard to monitor and control our AC usage and energy consumption. This is the problem we’re also trying to help with by creating Ambi Climate. Dry mode will indeed help with condensation, humidity and the resulting damage these two may cause to your home – with Ambi Climate you can see all the hours you’ve used your AC, different modes and temperatures (Ambi will set itself to provide the environment that you set through our Smart Modes) and ultimately, after some months, you’ll be able to compare this to your energy bills and see the changes and differences.


  6. In case of Inverter AC systems, as the compressor motor of the inverter air conditioner does not turn on and off all the time, but keeps working at low power, what happens to the evaporator coil temperature when the preset temperature is attained? Can an inverter AC continue to dehumidify a room as quickly and effectively like a normal (on/off cycling) AC?


  7. Thank you for your reply and associated information about compressor types and evaporator coils!
    You mention “the air won’t cool down as much when it goes through the AC”. That was exactly my doubt. If an inverter run compressor AC won’t cool down the air ‘as much’, it implies that the evaporator coil temperature wouldn’t be ‘as low’. That means the coil itself would continue to work at a higher temperature than what it had been before attaining the user defined temperature setpoint. Now will the AC be able to continue to dehumidify, or to be more precise, to be able to condense and extract moisture out from this air passing through it while running at fractional capacity? (Possibly not.)
    In that case, if I stay in a coastal, highly humid region beside the sea with mildly high temperatures, and my prime utility for my AC would be dehumidification, I would rather be better off with a conventional on/off cycling unit.
    Please comment.
    Kind regards.


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