Choosing an efficient air conditioner

Choosing an efficient air conditioner
As the summer is starting to grill us, many people have already started installing Air conditioners in their homes.

The most important thing to look for with an air conditioner is the star rating. You need to work out what size you require for the task and then choose the most efficient model that will perform the task.
The two main types of air conditioners for household use are window-wall systems and split systems. While both can be equally efficient, split systems tend to be more efficient for a particular size range as their components are generally less constrained by size (although this is not always true). Split systems have the advantage of being quieter indoors during operation but they are also more expensive. Some larger houses may choose ducted or packaged units. Be sure to check the stars before you buy.
A new innovation in air conditioner technology is the use of an inverter or variable speed drive in the motor system that drives the compressor (comes with Voltas, Hitachi and Onida now). While these systems tend to look less efficient at full load (ie their star rating at rated capacity is not always as high as conventional air conditioners), they tend to be very efficient at part load operation, which is a more common mode in a typical household. So if you are likely to use an air conditioner for long periods because you live in a hot climate, it may be worth considering an inverter system. They are, however, more expensive to buy, as a rule.
Sizing an air conditioner
The output capacity is a measure of the amount of heat that will be removed (cooling) or added (heating) to the room/s in your house by the air conditioner. The output range you need will depend upon your particular requirements. Air conditioner outputs are measured in kilowatts (kW). As an approximate guide for sizing a room unit allow:
125watts (0.125kW) per square metre of floor area to be cooled in living areas;
80 watts (0.080kW) per square metre of floor area in bedrooms.
These estimates depend on the climate and the efficiency of your house design (orientation, glazing and insulation levels).
It is advisable to get a full heating or cooling load calculation from an authorised air conditioning installer or manufacturer before you buy.

Simple thumb rule is that 1.5 tonne will do good for a 200 to 250 sq.ft area. And 1.0 or .8 tonne for areas lesser than 200 sq.ft.


Best suggestions as a user of AC: Go for brands like Hitachi and O General.

Star rated Air conditioners!!! Is it really worth buying star rated air conditioners (ac s)

Most websites on air conditioning ratings are now recommending you to buy an ENERGY STAR rated AC. Will these energy saving air conditioners will undoubtedly save you money? Yes it will when compared to the cheapest, least efficient on the market (since the ENERGY STAR ones will be at least 10% more efficient). The star rated will definitely be more efficient than anything more than 8 or 10 years old, because as they become less efficient with time and more over they have out dated electro mechanical parts.

I have done a small calculation based on the wattage consumption and found out the following savings could be achieved by using a 5 star rated Ac over a 0 star rated AC.

Let us consider a small house:

No of operating hours for AC per day: 6 hours
No of days in a year : 300 years ( leaving out 65 days for outing and other things)

AC tonne : 1.5 tonne

Electricity charges : Chennai, India rates are applied


The total energy bill for a '5' star rated Air conditioner for the above configuration and operating pattern is : Rs. 6793 per year

The total energy bill for a '0' star rated Air conditioner for the above configuration and operating pattern would be : Rs. 9887 per year


So you save Rs. 3094 directly on energy bills in addition to that you have reduced your CO2 emissions by saving energy.

Solar Powered Air Conditioners Coming To US Homes (Soon!)

Solar Powered Air Conditioners Coming To US Homes (Soon!)

Even though we are nearing the end of Summer, in many cities and states heat is still bearing down at full throttle.

And most homes in the US use air conditioners to cool off. In fact, most Americans use air conditioners to the tune of 16% of the total energy in the US. So obviously this is a huge market in the HVAC niche, which environmentalists and green minded entrepreneurs are rushing off to make more eco friendly. I don’t foresee anytime soon a plethora of middle Americans dumping their A/C, as this has been the norm for too long and most don’t know what to replace their A/C with. But there is growing awareness of the need to use less energy and to at least try energy-efficient cooling systems, and Americans are starting to seriously pay attention to this big energy hog.

However there is good news. A company named ChromaSun is making strides in this area and has a prototype in the works to bring a highly efficient earth-friendly air conditioner to US homes.

Their first revolutionary product is a Solar Powered Air Conditioner. This 10 foot long by 4 foot wide box (for lack of a better word) would cost about $15.52 a kilowatt hour to operate compared to $27.69 for an electrical air conditioner. And would cool off an average 1,500 square foot room with ease, according to ChromaSun. As the name suggests, the a/c would be powered by the Sun. The light from the sun would be converted to heat, which would then be converted to electricity. So you could potentially (very soon) cool off your home entirely off-grid. Or mostly off-grid anyway.

The cost has not yet been determined, nor a release date set on this solar-powered air conditioner, but keep an eye on ChromaSun—as they have a pulse on this massive and exciting industry.