Inverter Aircon Savings

Inverter Aircon Can and Cannot Save Money

Everyone nowadays is talking about inverter aircon. Advertisers said that end user can save up to 50% of their electric bill compared to the conventional or non-inverter aircon. Is this true? Well, let us talk about it, so keep reading. I actually say that inverter aircon can and cannot save money. Inverter aircon is a new technology; actually, not anymore very new as of this writing but there is no other technology so far newer than this in air conditioning world.

Inverter Versus Non-Inverter Aircon

Inverter aircon operates continuously in a variable speed. There is a mechanism inside that will control the compressor motor speed in order to maintain a certain temperature. For instance, the set temperature is 20’C. The compressor will full speed during start up to attain this temperature setting. Once this is attained, the compressor will slow down to a speed that is enough to maintain the set temperature, but it will not turn off. This process will not generate noise. On the other hand,  non-inverter aircon will operate in full speed to attain the set temperature. Once attained, it will turn off. When the temperature changes, it will turn on again at full speed then repeats the process. This process will cause issue: (1) The aircon unit is bit annoying as it will undergo turn on and turn off process. This is more pronounced during nighttime, (2) Every time the compressor turns on again, it will cause a high current spike. This will result to a certain level of power loss considering it will repeat the turn off and turn on process continuously.

Inverter Aircon Can and Cannot Save Money…How?

As claimed by many, inverter aircon can save money. I agree. I have both inverter and non-inverter type aircon installed in my house. I can say the difference. But, how come an inverter aircon can and cannot save money? What is the explanation of the cannot?

Inverter Aircon Cannot Save Money – When You Select the Wrong Size

An inverter aircon works on the principle of variable compressor speed. The lower the speed, the lower the power consumption and saving to the electricity bill. At start up, inverter aircon will just do the same how the non-inverter aircon does. But the difference will happen when the set temperature is attained. For the inverter aircon, once it reached the set temperature, it will slow down to a speed just enough to maintain the set temperature. So, if you are buying an inverter aircon that is undersized compared to the room area you are going to cool down, it will not reach the desired temp set point and it will continuously run under full speed and power. In this case, you may even spend more money on the electric bill. If the aircon is not heavily undersized but still smaller that the room area, it will able to attain the set temperature, but the level of compressor speed needed to maintain that temperature is not that very low. This results only to a partial saving that may be negligible to using a non-inverter aircon.

Inverter Aircon Can Save Money – If Selecting the Correct Size

Aircon sizes are rated in terms of horsepower (hp). You may hear ½ hp, 1hp, 1.5hp, 2hp and so on. These are the sizes that need to match to your room’s area. There are many sites that provided information on how to select the right horsepower. You can even ask your supplier to help you size your aircon. I have put a reference below.
Above values are good reference and I proved this. I have a room that size is close to 24 square meters. It is not high ceiling; just a typical room of a house. So, I selected a 1.5hp inverter aircon. The expectation is correct. I able to cool the room in a very short period. I noticed that only little amount added to my monthly electric bill. If your budget is good, you can even upsize a bit. Say for instance a room size of 22-25 square meter, you may buy 2 hp. You can maximize the savings on monthly bill for sure as you can attain the set temperature in less time which means only a short period of time the aircon operating on its full speed. Then the speed needed to maintain the set temperature is very low. But do not also exaggerate the size as price always comes with the horsepower size. It will take you too long to get the ROI.

How Much the Saving? Is it 20%, 30%, 40% or 50%?…

These percentages are often in reference to using the same horsepower non-inverter aircon. For instance, a 30% percent savings means that when I use a non-inverter aircon my electric bill is 100$. But if I used an inverter type aircon, my electric bill will only be 70$.

[(100$-70$)/100$] = 30%

So, how much exactly the saving is?… It is hard to tell. But if you select the right aircon horsepower for a room size and an aircon brand with an energy saving certificate and you are running the aircon more than 8 hours a day, you can surely experience a saving on your electric bill. I don’t want to discourage you, but I am hesitant to believe a saving of more than 40% as some manufacturers or suppliers claim. In their testing, they may consider the favorable conditions like very optimized aircon to a specific room, less to no heat generating appliances and so on that we cannot exactly duplicate in our homes.

Initial Investment and ROI Period

Inverter aircon has higher buying price as compared to the non-inverter type. It takes time before you can get the savings. I tried to check online of an aircon brand, and I found below:
The price difference is in the range of 280$ – 300$ when you buy a brand new.

Assuming 20% Saving

Assuming an aircon size of 1.5hp. Let us also assume to operate the aircon just 12 hours per day and a kW-hr cost of 0.22$. Based on below table, it will take 16 months before start realizing the savings. This is because inverter type has higher purchase price.

Assuming 30% Saving

It will take 11 months to realize the savings based on below table.

Assuming 40% Saving

It will take 8 months to realize the savings based on below table.

Assuming 50% Saving

It will take around 6.5 months to realize the savings based on below table.

Summary – Inverter Aircon Can and Cannot Save Money

  • Inverter type aircon is more efficient than the non-inverter type aircon
  • Inverter type aircon operates in variable compressor speed technology wherein just enough speed has been provided to maintain the set temperature
  • Non-inverter aircon has fixed speed (max level) and will turn off compressor once the set temperature has reached. It will turn on again once the sensed temperature is out of the set level. The turn off and turn on process will repeat continuously.
  • The numbers advertised for saving when using an inverter aircon is not accurate. It always depends to the actual scenario.
  • There will be no savings if the aircon is too small for a given room area
  • There are guides on how to size the aircon with respect to the room area, but one can upsize the aircon a bit if the budget permits to maximize the monthly saving


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