How to choose an air conditioner for an Indian summer

An air conditioner is a big purchase with a long tail of running costs. The right AC cools your room quickly and keeps electricity bills under control; the wrong one runs flat out all summer and still leaves the room warm. Star ratings, tonnage and "convertible" modes can be confusing, so this guide walks through what actually matters when buying a split AC in India.

The short answer

Choose the tonnage for your room size and conditions, prefer an inverter AC, and pick the star rating based on how many hours you'll use it. Budget for installation extras, and check the compressor warranty and local service network before you buy.

Tonnage: match it to your room

Tonnage is cooling capacity. Too little and the AC never catches up on hot afternoons; too much and you pay extra upfront for capacity you don't need. As a rough guide for a typical room with a standard ceiling height:

• Up to about 120 sq ft: 1 ton
• About 120–180 sq ft: 1.5 ton
• About 180–250 sq ft: 2 ton

Go up a size if the room is on the top floor, gets direct afternoon sun, has large windows, or regularly has several people or a kitchen nearby. In very hot cities, many buyers choose 1.5 ton even for medium rooms for faster cooling.

Inverter or fixed speed?

A fixed-speed AC switches its compressor fully on and off to hold the temperature. An inverter AC varies the compressor speed, running gently once the room is cool. Inverter ACs are quieter, hold the temperature more steadily, and use noticeably less electricity over long daily use. For most homes, inverter is the better choice, and most ACs sold now are inverters.

Star ratings and ISEER

In India, ACs carry a BEE star rating, from 1 to 5 stars, based on a measure called ISEER (Indian Seasonal Energy Efficiency Ratio). A higher ISEER means less electricity for the same cooling. The star label also shows the estimated annual energy use.

Which rating makes sense depends on use:

• Long daily use (many hours a day, most of the year, or hot cities): a 5-star AC usually repays its higher price through lower bills.
• Moderate use (a few hours a day, mainly summer nights): a 3-star AC is often the better value.

Rating standards are revised periodically, so compare the ISEER value and the label's annual energy figure rather than the star count alone, especially between older and newer models.

Condenser coils: copper or aluminium?

The outdoor unit's coils carry the refrigerant. Copper coils are generally easier to repair and are widely preferred for durability. Aluminium coils lower the price and can perform well, but can be harder to repair. In coastal areas, salty air causes corrosion, so look for coils with a protective anti-corrosion coating whichever metal you choose.

Features worth having

• Stabiliser-free operation: many ACs list an operating voltage range. If your area has big voltage swings, a separate stabiliser may still be wise — check the range against local supply.
• Convertible modes: let you run the AC at reduced capacity to save power on milder days.
• Washable, easy-access filters: clean filters keep cooling efficient. Some ACs have self-cleaning functions, which help but don't replace regular servicing.
• Wi-Fi and app control: convenient for switching on before you get home, but optional.
• Low-noise indoor unit: check the noise level in decibels if the AC is for a bedroom.

Most modern ACs use refrigerants such as R32 or R410A; the type matters mostly to the installer and isn't usually a deciding factor for buyers.

Installation: the hidden costs

The AC price often doesn't include everything:

• Installation may be free or charged, depending on the brand and offer.
• Extra copper piping beyond a standard length, wall-mount stands, drain pipes and core cutting are commonly charged separately.
• Ask for the brand's official rate card for extras, and make sure installation is done by an authorised technician — poor installation causes leaks and weak cooling, and may affect your warranty.

Warranty and service

ACs usually carry a shorter warranty on the product and a much longer one on the compressor — often five to ten years. Check what the compressor warranty actually covers (parts only, or parts and gas refill) and whether you need to register the product. A brand with service centres in your city matters, because ACs need regular servicing and quick repairs in peak summer.

When to buy

Prices and installation waiting times both tend to rise as summer approaches. Buying in the cooler months, or during big online sales, often gets a better price and a faster installation.

Checklist before you buy

1. What tonnage suits your room size, floor and sun exposure?
2. Inverter, for steady cooling and lower bills?
3. 3-star or 5-star, based on your daily hours of use? What's the ISEER?
4. Copper coils, and anti-corrosion coating if you live near the coast?
5. What installation extras will be charged, and at what rates?
6. How long is the compressor warranty, and what does it cover?
7. Is there an authorised service centre near you?