The two most important considerations when choosing a room air conditioner is the space in which it will be located and its BTU rating. The purpose of an air conditioner is three-fold. It should lower the temperature of the air, remove moisture from the air, and filter the air. Choosing too small or too large of a unit will reduce the efficiency of the air conditioner in terms of cost and cooling ability. A unit which is too large will cycle on and off, reducing the ability to dehumidify the room as it should and cost you more to run. A unit which is too small will not cool your room efficiently.
In terms of space, you need to measure your room dimensions. For squared or rectangular rooms, measure length and width, multiply the two numbers, and you have the square footage for your room. If more than one room is to be cooled, repeat this procedure and add the figures together to obtain the total square feet of the area to be cooled.
The recommended BTUs for areas in terms of square feet are noted below:
100-150 5000 BTUs
The BTU number tells you how quickly and effectively a unit can cool the room. Depending on the location of the room in which you place the air conditioner, the BTUs required to maximize efficiency should be adjusted for the following conditions:
Sunny locations – increase BTUs by 10%
Shady locations – decrease BTUs by 10%
Rooms occupied by more than 1 person – add 600 BTUs for each person.
Kitchens – add 4000 BTUs.
Also consider the ceiling height, insulation of the room, and the general climate type of the region you live in.
Room air conditioners can be installed in a window or can be built-in by cutting a hole through a wall. For window installation, measure the length, width and depth of the space under the glass when the window is open. Models can be installed in most single or double-hung windows. Accordian panels which generally come with window air conditioners allow for a secure fit. Some models can fit in sliding windows but require some kind of support system. For built-in units, although they are more expensive, they do not take up window space and can be installed through a wall for permanancy. This type of unit allows for a more airtight and secure fit. A frame is required to support the unit.
Saving energy saves you money and saves our environment. Look for air conditioners with a high EER(energy efficiency rating) of 10 or higher. Higher EERs reduce greenhouse emissions. Energy Star labeled air conditioners offer even more savings.