Inverter vs Non-Inverter AC: What Actually Changes

A fixed-speed AC has one speed. It runs at full power until the room reaches the set temperature, switches the compressor off, waits for the room to warm up by a degree or two, and starts again — all night. Each restart draws a surge of current, and the room swings between too cold and slightly warm.

An inverter AC changes the compressor's speed. It runs hard to pull a hot room down, then slows to a fraction of its capacity to hold the temperature steady. It rarely stops, avoids the restart surges, and matches its output to the load.

It depends on hours and the specific units, so compare the BEE annual-units figure on the two labels you are choosing between. As a sense of scale from our catalogue: Blue Star's 1 ton FB212DNU fixed-speed split has an ISEER of 3.52, while 1 ton 3-star inverter splits such as Lloyd's GLS12I3AGGSR (4.47) and Daikin's ATKL35XV (4.4) deliver about 25% more cooling per unit of electricity.

For an AC used 8 hours a night across a long summer, that difference covers the ₹5,000-₹6,000 price gap within a few years. For a guest room used a few evenings a month, it never does.

• A room used occasionally — a guest room, a study used a couple of hours a week.
• A rented room where you want the cheapest workable window AC and will move soon.
• A strict budget under about ₹30,000, where the choice is fixed-speed or no AC.