51 Ways to Save Energy on Air Conditioning


A lot of energy is used on air conditioning. Our air conditioners consume so much electricity, resulting in us need to pay for high electric bill every month. So, what are the ways to save energy on air conditioning?

1. Don’t Bring in Outside Air

Air conditioners use more energy when they need to process the warm outside fresh air instead of the cold return air. Most of the time, we don’t need to keep pumping in the fresh air because we already got enough oxygen by just opening the door and window. So, don’t introduce fresh air to your air conditioner or reduce it when possible.

2. Let the Air Conditioner Run All Day Long

Some people think that running the air conditioner all day is consuming more power. However, it is not always the case. If we keep turn on and off the air conditioner, it is actually more power consuming because the compressor will work at full capacity every time it is turned on. Instead, let it run the whole afternoon, maintaining a good temperature and low energy usage.

3. Place the Thermostat at the Correct Position

Avoid putting the thermostat in hot places. Many air conditioners rely on the thermostat to control the room temperature. If the surrounding temperature of the thermostat is warmer, the air conditioner misunderstood that the room temperature is warm too and thus, keeps cooling the room and wasting energy.

4. Shade the Outdoor Unit

The outdoor unit needs to reject the heat transferred from your room. Shading the outdoor unit helps to reduce the solar heat gain and thus, reduce the burden of the outdoor unit. Furthermore, it also protects the body of the unit. Therefore, improving the efficiency of the air conditioner.

5. Use the Motion Detection Function

Some air conditioners have a motion detection function to save energy when we are not present in the room. Hence, if your air conditioner has the function, be sure to use it. However, keep in mind that don’t put an object close in front of a motion detection air conditioner because the air conditioner may misinterpret the object as a person and thus, reduce cooling power unnecessarily.

6. Have a Return Vent in Every Room

The best is to have a return air vent in every room so that the air conditioner knows the average return air temperature and therefore, provides optimal cooling. Otherwise, the air conditioner will keep cooling the room even though the room is already very cold because the air conditioner doesn’t know it without the return air.

7. Set a Higher Temperature

Don’t set the temperature anywhere below 20°C because the air conditioner will never reach that low of a temperature. Thus, the air conditioner keeps trying to cool the room and wasting energy. Instead, set the temperature at above 25°C for optimal energy usage.

8. Don’t Bend the Duct

Do not allow unnecessary bend to the duct. Every bend is a resistance to the airflow and the air conditioner needs to work harder to push the air. Flexible ducts are very easy to get bent due to their softness and they’ll completely block the airflow which is even worse. Thus, make sure you don’t bend the duct.

9. Use a Split Air Conditioner

Split air conditioners generally have a higher energy efficiency than both window air conditioners and portable air conditioners. Although split air conditioners cost more, they use less energy and can save you more in the long run.

10. Close the Toilet Door

Believe it or not, some people only close the main door but never close the toilet door. The toilet has a decent space to be cooled and it is also very wet. Thus, the air conditioner needs to work harder on both cooling and dehumidifying the toilet which is totally unnecessary.

11. Schedule the Air Conditioner

It is wise to schedule your air conditioner to turn off 30 minutes to an hour before you wake up. If it is an hour per day, it is 365 hours per year. What about 10 years and you have 5 air conditioners? They add up and save you tons of energy in the long run.

12. Let the Air Conditioner Blow at You

Generally, it is not good to have the air conditioner blowing cold air directly at you for a long period of time. But, if it is just a short while, consider letting the air conditioner blowing at you. However, you need to set the temperature even higher while doing so, otherwise, you are not saving any energy.

13. Don’t Put the Supply Vent Near the Window

Cold supply air will quickly become warm supply air if you put the vent near to the hot window. If so, you naturally will set a lower temperature for your air conditioner which leads to higher energy usage. In addition, you may have the risk of condensation on the vent when it’s too hot outside. So, make sure to avoid putting the supply vent near the window.

14. Use a Solar Air Conditioner

Solar air conditioners obviously can save you tons of energy because solar energy is free. Nowadays, solar air conditioners are getting traction and the cost went down a lot. However, it is still costly to install a solar air conditioner. But, if the return on investment makes sense, consider using a solar air conditioner.

15. Switch Off the Power

Air conditioners still consume power even when they are not in operation. It is called standby power consumption. So, turn off the A/C switch to cut off the power supply to your air conditioner entirely. However, it is not recommended to do so if you are using it on a daily basis because you may damage the air conditioner. But, switch off the power if you are going for a vacation.

16. Make Sure No Duct Leakages

It is easier than you think for the duct to leak air into the ceiling and attic. Access to space above the ceiling and go to your attic to check if it is cold up there while you are using the air conditioner. If you feel the cold, there is a high chance that the duct is leaking cold air and wasting energy.

17. Use a High Efficiency Air Conditioner

In most countries, the higher the energy rating, the higher the efficiency of the air conditioner. Furthermore, the higher the efficiency of the air conditioner, the lesser the energy usage. Thus, find out which air conditioner is the most efficient one, compare their price and make the purchase.

18. Don’t Hide the Air Conditioner

Some people don’t like to expose their air conditioners and they conceal them with cabinets or cover them using the ceiling. However, they are choking their air conditioners and wasting energy because air conditioners must have smooth and sufficient airflow in order to work efficiently. So, don’t conceal the air conditioner.

19. Install an Air Curtain

If for any reason you need to keep the door open while using the air conditioner, install an air curtain above the door to form an invisible curtain to prevent cold air from escaping out your house and wasting energy. All shopping malls have either air curtains above the door or use automatic sliding doors to conserve the energy on air conditioning.

20. Use the Quiet Mode

Some air conditioners reduce the airflow beyond the minimum fan speed setting when operating in quiet mode. Many people don’t realize that the air conditioner operates at the lowest capacity in quiet mode. Thus, if you don’t need so much cooling, use the quiet mode to save some energy.

21. Insulate Your House

This is a big one. Insulating your house can cut the capacity needed for air conditioning by half and therefore, saving 50% energy usage. However, insulating a house is very expensive and not all houses are suitable. Thus, if you can, insulate your house or just the room to save energy.

22. Make Sure the Air Distribution is Good

Don’t put the supply vent in a corner because you will not feel the cold and you’ll set the air conditioner to a lower temperature which leads to higher energy usage. Thus, make sure the supply vents are evenly placed to have a good air distribution.

23. Use an Air Cooler

If you are living in a hot and dry climate region, an air cooler works very well and can save you a lot of energy on air conditioning. Air coolers are also known as evaporative coolers or “ventless” portable air conditioners are making the air more humid while cooling it down. Thus, air coolers don’t work very well in humid climates.

24. Install the Correct Duct Size

Don’t suffocate your air conditioner with a small duct size. The air conditioner works harder if the duct size is small because the friction is greater. However, the duct also cannot be too big because the air distribution may be impossible to balance. So, make sure you install the correct duct size.

25. Close the Door and Window

It is obviously not a good idea to leave the door and window open when using the air conditioner. Hot air will be coming into your house through the door and window. At the same time, cold air will be leaking out and wasting lots of energy. So, check behind the curtain to make sure all the windows and doors are closed while using the air conditioner.

26. Use the Geolocation Feature

Nowadays, many air conditioners are built-in with smart control features that allow you to control from a mobile app. On the other hand, people living in a very hot climate need to keep their house cool even when they are out for a short while. Hence, you can use the geolocation feature to switch on the air conditioner only when you are nearby your house and not wasting too much energy.

27. Don’t Put a Filter on the Return Vent

Many people like to put a filter on the return vent. However, they are doing more harm than good to their air conditioner because extra filters will reduce the airflow and so, the air conditioner needs to work harder and longer. Thus, wasting energy.

28. Use an Inverter Air Conditioner

Inverter air conditioners are more efficient than conventional non-inverter air conditioners. Inverter air conditioners can regulate the cooling power as necessary. Besides, they don’t turn on/off their compressor but maintaining a steady speed. Thus, using an inverter air conditioner will significantly reduce energy usage.

29. Clean the Filter and Coil

If an air conditioner does not have sufficient airflow, it’ll work longer and harder to achieve the desired temperature. Hence, make sure to help the airflow of your air conditioner by cleaning the filter and coil regularly. In addition, call for a professional service once a year to clean your air conditioner thoroughly so that the air conditioner works efficiently all the time.

30. Switch to ECO Mode

Many air conditioners are equipped with ECO mode or energy saver mode. Be sure to switch to ECO mode for as long as you can to save energy. If you have many air conditioners, they can save a significant amount of energy in the long run.

31. Use a Water-Cooled Air Conditioner

Water-cooled air conditioners are more efficient than the air conditioner we normally use which is an air-cooled type. Water-cooled air conditioners use water to reject heat instead of the surrounding air which can change anytime. Thus, use a water-cooled air conditioner if applicable.

32. Don’t Use an Air Conditioner with Fancy LED Lights

Some air conditioners have fancy LED lights on the indoor unit and honestly, we don’t need the LED lights and they are wasting energy. While it is not significant, but if you have many air conditioners, they do make a noticeable difference in the long run. In addition, if you don’t need it, why not save some energy even it is just a little.

33. Turn Off the Fan

Many people are told to use the fan to save energy on air conditioner however, I find it is only partially true. You can try turning on the fan but, you will not feel like you are in an air-conditioned room which may lead to you set a lower temperature for the air conditioner and thus, wasting energy. So, if you need the air conditioner, turn off the fan.

34. Use the VRF System

VRF air conditioners are known for high energy efficiency. VRF system can distribute the refrigerant according to necessity. Furthermore, air conditioners with variable refrigerant temperatures which can further boost their efficiency, only available in VRF system. Thus, if you need a larger air conditioning system, consider the VRF system.

35. Ventilate the Outdoor Unit

Don’t ever put the outdoor unit at not well-ventilated places because you may damage the unit and also, the air conditioner will consume a lot more energy. The outdoor unit needs good ventilation to perform well. Thus, make sure you install the outdoor unit an open area where the airflow is smooth and unobstructed.

36. Use the Sleep Mode

Many air conditioners have the sleep mode function. Try to use the sleep mode when you are about to sleep because the air conditioner will automatically turn up the temperature without waking you up and save energy. When it is time for you to wake up, the air conditioner already turns itself back to the original temperature setting.

37. Don’t Use an Air Deflector

Some people like to install an air deflector on their air conditioner to shift the airflow away from them. However, adding an air deflector potentially obstructs the normal airflow of the air conditioner and thus, reducing its performance and wasting energy. So, try to relocate your furniture if you had the air conditioner installed in the wrong position.

38. Tint the Window

Solar heat gain is one of the major factors that affect the energy usage of the air conditioner. Tinting your windows can effectively reduce solar heat gain. Therefore, the air conditioner doesn’t have to waste energy on cooling the extra unnecessary heat gain from the window.

39. Make Sure the Duct Insulation is Good

Many houses, especially the old ones, have bad insulations that are not able to effectively insulate anymore. Over time, duct insulation can shrink, grow mold and be detached from the duct. Bad insulations will cause energy loss. So, make sure to check the insulation condition including the flexible duct.

40. Use a Geothermal Air Conditioner

Geothermal air conditioners have excellent efficiency however, they are very expensive and only applicable to certain places. A geothermal air conditioner absorbs/rejects heat using the ground. If you have the budget and geothermal air conditioners are available at your place, consider getting one because it can save you a lot of energy in the long run.

41. Conduct a Duct Cleaning Work

The air conditioning duct will eventually be full of dust even though the filter is changed regularly because the filter can’t block 100% of the particle. Hence, duct cleaning work is often needed every 5-7 years. Cleaning the duct not only makes your house air cleaner, but it also saves you energy on the air conditioning system.

42. Use the Dry Mode

If you don’t need so much cooling, you can use the dry mode for comfort. In dry mode, the air conditioner main objective is to dry the air instead of cooling the air. So, if feasible, use the dry mode instead of the default cool mode to save some energy.

43. Install the Tesla Solar Roof

Needless to say, install the Tesla solar roof can definitely save you tons of energy. It may even let you go off-grid if it is big enough. Thus, if you are going to replace your house roof, consider using solar power for your entire house including powering all air conditioners.

44. Don’t Use a Portable Air Conditioner

Portable air conditioners are known for bad efficiency. Some portable air conditioners are as pricy as split air conditioners but the split air conditioner is much more efficient. So, if you don’t really need a portable air conditioner, consider other types of air conditioners.

45. Use a Bitcoin Mining Space Heater

Believe it or not, there are a lot of bitcoin mining space heaters in the market now. Basically, it is a space heater that heats up due to Bitcoin mining. So, you can get some Bitcoins while using the heater. However, it doesn’t save energy but it saves you money.

46. Put Light Color Curtains on Your Windows

I once read an article saying that light color curtains reflect the sunlight and thus, reduce the heat gain in the room and save energy on cooling. Logically, it is true. However, I’ve not tested it. Let me know if you don’t feel as much heat as using dark color curtains when using light color curtains.

47. Mist the Outdoor Unit

There are many types of condenser misting systems out there in the market that you can buy for a fairly affordable price to install on the outdoor unit. A misting system will spray mist or water vapor around the outdoor unit to reduce the temperature and make the outdoor unit more efficient. Therefore, saving energy. However, some people mentioned that the system increases their water bill.

48. Use a Heat Pump

Use a heat pump for cooling and heating instead of an air conditioner and a space heater. Heat pumps work exactly like air conditioners but they can provide heating as well and they are very efficient. So, if your area doesn’t go below zero degree Celsius, consider using a heat pump over a space heater to save energy.

49. Tighten the Window and Door Gaps

Hot air can come into the room through the window and door gaps. So, check the gaps especially the window. Change the sealing rubber to make sure the window can be fully closed. Make some repairs if necessary. All and all, these gaps can bring a lot of heat into the room and thus, the air conditioner needs to use more energy to cool the room.

50. Install the Correct Size Air Conditioner

Needless to say, bigger size air conditioners use more energy than smaller size air conditioners. Hence, don’t use an oversized air conditioner. Not only do you use more energy, but you also will feel too cold as an oversized air conditioner can’t reduce much of its cooling power to match the room. So, be sure to install the correct size air conditioner.

51. Use a Fan

Ultimately, the best way to save energy is don’t use an air conditioner. Sounds extra, isn’t it? But, seriously, we should try to use a fan whenever we can. Besides, open the window to get some natural ventilation instead of relying on the air conditioner all day long.

Design Engineer Starter Pack

Many junior engineers don't get enough guidance and support from their seniors and managers. I believe junior engineers should have a chance to gain access to high-level design skills and tools. So, kick start your HVAC design journey with seven (7) calculators, five (5) diagrams and three (3) charts.

Yu Chang Zhen

Hi, I hope my article was helpful to you. I'm actually quite enjoy working in the air conditioning industry. Maybe it is because Malaysia is a very hot country!

Recent Posts