So it started out as a way of making people comfortable. Right? Well, not exactly. In 1882, thanks to Thomas Edison, the first electric power plant opened in New York making it possible for the first time to have an inexpensive source of energy for residential and commercial buildings. And by 1889, central station refrigeration was used in large cities to preserve foods and documents. It was well known that a cool surrounding could preserve foods and other perishables for a long time. But what was not well known was how humidity and heat were related. Then in 1902, Willis Carrier built the first air conditioner to combat humidity inside a printing company. Controlling the humidity in printing companies and textile mills was the start of environment management.

How to Buy a Room Air Conditioner

02/07/12

Whether replacing an older, less efficient unit, or buying a new
unit for a previously un-air conditioned room, you should be
impressed with the performance of newer models. The major
attributes to consider include:

Cooling Capacity – The ability of a unit to cool an area is
measured in BTU/hour. The higher the BTU, the more cooling power
the unit has. However, don’t chose a model with too much cooling
capacity, it will cycle on and off too often, wearing on the
machine and not staying on long enough to remove humidity from
the air. Make sure you have a rough estimate of the sizes of the
rooms you want to cool (in square feet) before you start
shopping.

Energy Efficiency – Look for high efficiency units. Efficiency
is measured by the EER (energy efficiency rating). All new units
sold in the US must clearly display the EER. The higher the EER
the more efficient the model and the lower your energy bill. A
model with an EER of 10 should use about 20% less energy than
one with an EER of 8.

Installation Requirements – Make sure that the unit is the right
size for the window you plan to mount it in. Also, make sure you
have enough help in installing the unit (most are awkward and
very heavy). Some require installation of a metal shell, while
other require special electrical wiring (220 volts) Other
attributes to consider are listed below.

Types:

Window versus Portable– Window units are mounted in a window.
Portable are on wheels with a hose for hot air that must be
vented out a window. If you are renting, or only need to cool
one room at a time, consider a portable unit.

Wall Units – Wall units are designed to be mounted in holes cut
into the side of exterior walls. They don’t take up window space
and may be more difficult for burglars to use as a means of
entry. However, wall units require significantly more
installation effort than similar window units. Attributes:

Thermostat sensitivity – How closely a unit can maintain a given
temperature.

Noise Level – Today’s units are quieter than older ones. Listen
to the unit in the store before you buy.

Air Flow – Adjustable louvers direct the air up, down, right and
left. Some models have motorized louvers to blow cold air around
the room. Most models have the ability to switch from fresh air
to recirculating. Switch to outside air when you want to air out
the room, switch to recirculate on the hottest days when the air
conditioner is struggling to cool the room.

Low profile models – Some models hang below the window,
minimizing the area of sunshine that they block.

Timers – Some units have timers to turn on or off on a schedule.
Set the unit to turn on before you come home from work.

Filters - Some units have filters to remove allergens and odors
Remote Controls - Some have remote controls so you can activate
from across the room.

Dehumidifying Ability – Part of creating a comfortable
environment in the summer is reducing the amount of humidity.
All air conditioners provide this benefit. The effectiveness is
more dependent on the specific operating situation of the unit
that on the unit itself.

Buy during the fall or winter to get lower prices. Air
conditioners may be out of stock during the peak summer months.