With the dog days of summer just around the corner, the perfect time to shop for a new air conditioner is now. There are numerous factors to consider when you’re shopping for an air conditioner, including whether your home can accommodate a ductless mini-split system, a built-in wall assembly, a window unit, or a portable model. But all air conditioners have one thing in common: They must be sized properly in order to effectively lower the temperature and remove excess moisture from the air, resulting in a comfortable, cool indoor environment. When you’re shopping for an appropriately sized air conditioner, a number of factors come into play, including the general climate and average summer temperatures in your region of the country; the square footage of the room or rooms to be cooled; the installation location in the wall, window, or ceiling; the number of people typically occupying a room; and the amount of insulation in the home. An air conditioner that is too small for a given area will not be able to cool the space efficiently, while an air conditioner that is too large will tend to cycle on and off too rapidly, wasting energy and impairing the unit’s ability to remove humidity from the room.

Air conditioners are rated by their seasonal energy efficiency ratio (SEER), and their capacity is expressed in British thermal units (BTUs). home ac unit coilsThe BTU rating gives an indication of how quickly and effectively a particular unit can cool the room where it is located. hard start kit for ac unitMost home air conditioners sold in the United States range from around 5,000 BTUs to more than 20,000 BTUs.air handling unit qualification“Since we measure all of our heating and air-conditioning units in BTUs, it’s important to know how many BTUs your living space requires so you don’t buy a unit that is too large or too small. Another common measurement that heating and air-conditioning units are assigned is ‘tonnage.’ But don’t let this confuse you—one ton is just 12,000 BTUs!”

Correctly sizing an air conditioner for a given room requires a tape measure and a few simple calculations. The first step is to determine the size of the room where the unit will be installed. offers a handy sizing calculator to determine the correct amount of BTUs needed for a given room or set of rooms. The calculator requires the dimensions of a room, in length and width; the type of room, such as kitchen or bedroom; the number of people typically in the room; and finally, the exposure of the room—whether it is very sunny or shaded. Once you plug in the appropriate information, the calculator will determine the correct size air conditioner in BTUs. If you are cooling two adjacent areas, or if your room is odd-shaped, determine the square footage of each space as if it were a separate room, and then add the two measurements together to get a total amount of BTUs. According to the U.S. Department of Energy, another rating that homeowners should consider when purchasing a new room air conditioner is the Energy Efficiency Rating, or EER, which represents the cooling capacity of a unit in BTUs per hour divided by the watts of power consumed at a specific outdoor temperature (usually 95 degrees Fahrenheit).

The EER rating is found on the yellow Energy Guide label on the air conditioner, and it typically ranges from 8 to 11.5. An EER rating of 10 or higher is the most efficient and will yield the highest savings on monthly electric bills. A higher EER also helps the environment by reducing greenhouse emissions. offers a large selection of mini-split air conditioners and accessories from the top manufacturers in the industry, and features a variety of informative tools and instructional videos on its Web site. Written Written Reason for Choosing Split AC over Windows AC : - Compressor can be installed far away from the room and thus reduces noise associated with the ac system. The indoor unit requires only small space and can be installed any where in the room.Cooling/ conditioning of the room is uniform when compared with window ac system. Window ac cools only near the window and is not uniform across the room that requires to be cooled. Splitac consumes less power (more efficient) compared with window ac system.

Higher capacity ac systems are not possible with window ac system. In split ac one can have above 2 ton capacity systems.To Konw More About AC :  Buy AC at Best Price Online in IndiaDon't let the initial low cost of an off-the-shelf window-sized air conditioner fool you. Before long, you'll be paying far more for that cool air than you would with an alternative such as geothermal. That back bedroom is just too hot! Maybe “they” didn't run a big enough duct, or you’ve never had AC there.Window-sized air conditioners may seem like a good deal, but they're woefully poor users of energy.It doesn’t matter if you’re in a four room apartment or a single family home, the weather outside is hot. The first stop for most people is the home improvement store, Amazon, or whatever else is available in a moment of desperation. We purchase a $200 window or "through-the-wall" air-conditioning unit, and pay tremendously high energy bills for a woefully inefficient product. Let's look at some of the real and intangible factors with regard to the cost of installing a window air conditioner, some of which may not have come to mind.

A through-the-wall air conditioner is typically chosen in response to the following question: “What is the largest number of BTUs I can get for the least expense?” Here a short list of things that may be wrong with this line of thinking: The window AC is likely either oversized or undersized for the space, each of which wastes energy A through-the-wall air conditioner is likely rated for an EER (energy efficiency rating) of 10. The #1 bestselling window AC on Amazon is a Frigidaire FRA052XT7 5,000-BTU Mini Window Air Conditioner, with a 9.7 EER. The cost is $119.73.  As I stated earlier, we buy “cheap” in a pinch; Not really …there’s more… If you’re shopping for high efficiency window units, the next best option is the Friedrich SQ05N10B 5,200 BTU - ENERGY STAR - 115 volt - 11.2 EER. Still, a long way to go to measure up to the minimum standards of 13 SEER for home air conditioners, and they’re getting pricey at $578.94 on Amazon. Installation rarely works out the way instruction show, and the finished product is typically considered, even by the installer/homeowner as "poor at best".  

This results in increased thermal gains due to infiltration of air, solar gains, and other losses in efficiency. The install may even be a safety hazard. One report in 2011 states that Poorly Installed AC Units Cost New York City $180 Million in Fuel Consumption each year and the New York Times reported in a similar article that it was found that the average gap size for an AC unit was about the size of a fist, and “The cost of fuel lost to such energy waste is equal to the total cost of cooling the building alone…”. I have visited many homes and businesses over the last 30 years in which they've installed a window air conditioner(s) and complained of increases in energy expenditures of $50-$200 per month. Many of these homes could be completely conditioned with geothermal HVAC systems for fraction of that kind of energy cost. Beyond all of this, first cost is so low for the installation of window air conditioning units that it has become epidemic in many areas, even being used in office buildings and residential apartments.

Now, let’s continue the list of adverse results from these unsightly pimples, commonly called window air-conditioners.  Window air-conditioners can result in: Proportionally high CO2 emissions Increased noise pollution proportional to the number of window ACs in a building Increased safety risks and equipment hazards on ground level (and even upper level) installations A greater security risk (often because of poor installation) Below is a chart depicting energy consumption of the typical 1500 ft.² house using window air-conditioners (10 SEER), and conversely using a geothermal HVAC system (20 to 40 EER). To be fair, it's not uncommon for a home that uses only through-the-wall air-conditioning to use less energy per square foot than a home that uses central air-conditioning. This has to do with energy habits. We've all been in homes where the occupants only air-condition the living room during the day and then just the bedroom at night. This is a good energy habit, and can also be effectively applied with HVAC (ducted) systems using zoning (a well installed duct system with automatic dampers to cool and heat only the rooms occupied).

Much like energy efficiency in vehicles, we often feel we can't afford the costs associated with high efficiency products, when in reality the economics show a much different picture. It’s hot out there. Take a moment and “look before you leap”.  Grab a cool drink and consider the resources available.  You’ll make the right decision when you “Think Green”. Geothermal Cooling and Heating; Sharing Energy with Mother Earth Jay Egg is a geothermal consultant, writer, and the owner of EggGeothermal. He has co-authored two textbooks on geothermal HVAC systems published by McGraw-Hill Professional. © 2016, Green Builder Media. This article is the exclusive property of Green Builder Media. If you would like to reprint this content, you are free to extract a short excerpt (no more than 1/4th of the total article), as long as you 1. credit the author, and 2. include a live link back to the original post on our site. Please contact a member of our editorial staff if you need more information.