An inverter AC has an electrical device called 'inverter' which converts fixed frequency electricity (50Hz in India) to a variable frequency (for example from 10Hz to 100Hz). This enables the compressor of the inverter AC to run at different speeds to save electricity. For example, a 1.5 ton inverter AC becomes a 0.3 Ton AC by running at a low speed when the cooling load is less and becomes a 2.5 ton AC by running the compressor faster when the cooling load is more. Because an inverter AC can vary its cooling tonnage output according to the load, it is very efficient and saves electricity usage. Thus an inverter AC means an AC with a variable speed compressor which can save electricity. The disadvantages of inverter Air Conditioner is that it is more expensive than a regular AC. But the savings in monthly electricity bill with inverter AC use, will pay for the extra upfront cost of inverter AC in a few months.
The best AC to buy in India is an inverter AC, because there are so many advantages for inverter AC Vs normal AC. The inverter AC not only saves electric power cost, but is more silent and comfortable with steady continuous cooling.
Rather than the stop and start cycles of a normal AC, the inverter AC compressor does not stop running while the inverter AC is switched on. The inverter AC controls the cooling of a room by adjusting the speed of its compressor to suit the cooling needs. Thus the inverter AC will run at very high speed for a short time when the AC is switched on, to cool the room very fast, faster than a non-inverter normal AC. When the set temperature on the thermostat is reached, the inverter AC compressor slows down with just enough speed to maintain the set temperature by compensating for the heat coming into the room.
To give an example of a 1.5 Ton inverter AC, as soon as it is switched on, its compressor will run at say 150% of rated speed to cool the room fast till the set temperature has been reached and then will slow down to say 10% of its rated capacity which is just enough to maintain the cool room temperature by compensating for the heat coming into the room. This means that the 1.5 Ton inverter AC in our example here will be running as a 0.15 Ton AC most of the time and as a 2.25 Ton AC at the beginning when it is cooling the room very fast. Because of this ability of inverter AC to vary its AC ton according to needs, it makes inverter AC running cost so low that inverter ACs become the cheapest AC to run in India.
The advantages of an inverter AC over a normal non-inverter AC are as follows:
The graph below shows the room temperature of a normal AC compared to inverter AC and graphically shows the temperature difference in a room cooled by an inverter AC and a normal AC.
The difference between inverter AC and non-inverter AC is that a normal non-inverter AC compressor works with just one speed compared to the variable speed compressor of the inverter AC. So a normal AC works by shutting down its compressor when the set room cooling temperature has been reached and restarting its compressor when the room gets warmer and repeating this cycle. An inverter AC, on the other hand, does not stop running but runs at very low speeds to give just enough cooling to maintain the set cold temperature of the room.
How the inverter AC works is explained as follows: first, the inverter in the inverter AC converts the incoming 50 cycles per second or 50Hz Alternating Current AC electric voltage to DC voltage. The DC voltage is then converted back to AC voltage with the ability to change the frequency of the Alternating AC current. This device can be called a VFD (Variable Frequency Device).
The speed of electric motors depend on the frequency of the Electric Voltage driving the motor. A higher frequency electric current will make the motor run faster, and a lower frequency will make the motor run slower. Thus variable frequency enables the main compressor motor of the inverter AC to turn at different speeds. With the fixed 50Hz AC of our electric supply, the compressor motor of a normal air conditioner can only turn at one speed, but with a variable frequency, the compressor motor of the inverter AC can run at different speeds, from very low to very high speeds. There are many advantages if Air Conditioner compressor can be run at different speeds. It is the ability of an inverter AC compressor to run at different speeds that lead to the power savings in an inverter AC.
A 5 star normal AC is the most efficient normal AC, but it consumes more electricity than a 3 star inverter AC. So a 5 star AC vs inverter power consumption figures show that the inverter AC is better. This is because inverter and non-inverter AC works on a totally different principle as explained earlier. In a regular AC, the compressor has only one speed and the cooling is controlled by on-ing and off-ing the AC compressor. As explained, this is a very inefficient way for an AC to work. So even a 5 Star non-inverter normal AC will not be as good as a 3 Star inverter AC and a 5 Star non-inverter normal AC consumes more electricity than a 3 Star inverter AC
An inverter compressor in AC solves all the disadvantages of the normal AC and saves more than 40% on electricity bills as claimed by some of the manufacturers. Apart from this the inverter AC is very silent compared to a normal AC and the compressor lasts much longer, because it is never stressed.
When an inverter AC is put on, the compressor starts slowly and picks up speed gradually and reaches a higher speed than a normal AC for a short period to cool the room faster than a normal AC. Once the set temperature of say 22 degrees C is reached, the compressor slows down and has just enough speed to maintain the set temperature of the room. The compressor never stops while the AC is on; it just runs very slowly cooling the room just enough to maintain the set temperature. The variance in temperature in the room will be in decimals, in our example of 22 degrees it may go down to 21.9 and up to 22.1 degrees, which is negligible.
A normal one ton AC uses on an average about 1.25 units of electricity every running hour. This of course will vary depending on many factors like outside temperature, insulation factor of the room, etc. but 1.25 units is about the average power consumption of a regular non-inverter 1 Ton AC. The 1 ton inverter AC power consumption per hour would be about 40% less than that of a one ton normal AC. That means a 1 Ton inverter AC power consumption per hour will be about 0.75 units of electricity. Assuming 8 hours of operation per day, that will be 10 units of electricity per day for normal AC and only 6 units per day for a 1 ton inverter AC.
Thus the monthly power bill for a normal AC, assuming Electricity cost at Rs.5- per unit, will Rs.1,500- per month compared to Rs.900- for a 1 ton inverter AC. Therefore the saving in electricity cost of a 1 ton inverter AC for a month is Rs.600-, and Rs.7200- per year.
In the above example let us say that the 1 ton inverter AC costs Rs.10,000- more than the normal 1 ton AC, then with the monthly electric bill saving of Rs.600 per month, you will have paid off this extra money for the inverter AC in a matter of about one and half years. If you use the inverter AC for 5 years, then you will have saved more money with the inverter AC than the cost of the AC itself.
Apart from the cost savings in the running costs of an inverter AC, you will have a much more silent AC. The room temperature with an inverter AC will be always comfortable without the room becoming too cold for some time and then becoming too warm like with a normal AC.
We have a dedicated page showing all available models of inverter air conditioners available in India and this is the clickable link to it: Best inverter split AC available in India.
One important consideration when buying an inverter AC is the Star Rating of inverter ACs. We have pages explaining what star rating of inverter ACs mean and also how much more monthly electric bill you can save by buying a 5 star inverter AC instead of a 3 star inverter AC.
This is the link to best online deals in inverter AC on Amazon.in
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