Here's a quick guide to how you can get the most from your AC shopping this summer.

When the ceiling fan does nothing to cool you down, you know it's time to bring out the big guns. With summers getting longer and hotter, air-conditioners are proving indispensable. But they cost a lot and consume heavy power. Here's a quick guide to how you can get the most from your AC shopping this summer.

Split or window?

While window ACs are cheaper than split ACs, the price gap is narrowing fast. “Split ACs are easy to install, aesthetically more pleasing and give uniform cooling,” says Anup Bhargav, Product Group Head, Godrej. The noise and leakage levels are also lower.

Also, window ACs could prove a security risk if located on the ground floor. According to Mahesh Krishnan, Sr V-P (Consumer Electronics) Samsung India, the company has stopped making window ACs. In a couple of years, window ACs will be phased out completely.

1 or 1.5?

One tonne or 1.5 tonnes is the first question yours sales person will ask. Says B. Thiagarajan, President, Blue Star: “The size of the room, the floor on which the room is located, whether it faces east and how many people will use the room will decide the AC capacity.” The bigger the room, the higher the floor, the more number of people and direct exposure to sunlight means a higher capacity AC is required. Adds Bhargav: “The basic thumb rule states that a 1 tonne air conditioner is enough to effectively cool a room having size up to 100 square feet. In a typical room 20% space is occupied by furniture and other items. So a 1 tonne AC can be installed in a room of up to 120 square feet.”

What star?

All ACs come with star ratings, which has been made mandatory by the Bureau of Energy Efficiency (BEE). Ratings range from 1 star to 5 star, with 5 being the most energy efficient. Ratings are based on the Co-efficient of Performance (COP), which is the measure of every watt of cooling delivered for every watt of energy consumed. “You can get more than 30 per cent extra efficiency by using a new, 5 star product,” says Samsung's Krishnan.

You might pay more for a 5 star AC, but you pay less on electricity bills. Companies keep upgrading technology, so watch out for newer and more energy-efficient models. For instance, Godrej has a new range that reportedly gives power savings that's up to 20 per cent more than other ACs in the same bracket. A typical 5-star AC consumes around 1570 watts/hr. “Godrej's Green Balance AC uses R290, a hydro carbon refrigerant rather than regular refrigerant. So they consume only 912 watts/hour for a 1 tonne AC, which is less power than a hair dryer,” says Bhargav.

It's important to remember that star ratings are revised every two years by BEE. What's 5 star now could become 4 star in two years as technology advances and ACs become more efficient.

Frills and fancies

With competition running as high as temperatures, brands keep adding extra features. These range from filters to eliminate micro-organisms to inbuilt stabilisers to regulate voltage during power surges to even Vitamin C filters to reduce stress and soften skin! These features are secondary functions, added on to maximise user comfort but have negligible impact on the AC's efficiency.

Maintenance

Your purchase must come with warranty and after-sales service details. The price includes installation kit with insulation copper wire, so don't pay extra. Never skimp on the stabiliser, since voltage fluctuations can kill the AC; buy a reputed brand. Ensure that only a trained company technician installs the AC. Thiagarajan says that the “right temperature at which to run an AC is 23 or 24 deg. C, as there is least power wastage at that temperature.” ACs must not be run for more than 10 hours at a time, as carbon dioxide levels build up. Finally, get them serviced at least once a quarter to prevent fungus build-up.

How much is too much?

The Bureau of Energy Efficiency has a calculator to figure out how much electricity your AC consumes. Check out the Energy Calculator tool at www.saveenergy.co.in.