As a way to gauge the differences between brands and models, the portable air conditioner BTU output indicates the cooling capacity of a particular air conditioning unit which corresponds to room size. Basically, the bigger the BTU output the more cooling potential a portable unit has. While it would be uneconomical to continually run any air conditioner at its capacity, the BTU output provides you with a good idea of a portable air conditioner's capability. BTU output does affect price to a certain extent, but there are nevertheless very affordable portable air conditioners that generate a high number of BTUs.
Portable Air Conditioner BTU Range
Portable air conditioners are defined as standalone units with durable casters for easy moving. They are space saving and can effectively cool small to medium-size rooms. The range of BTUs they are able to generate runs from roughly 5,000 up to 14,000. A portable unit producing 5,000 BTUs can ably cool a room from 150 to 250 square feet in size, while the more powerful 14,000 BTU model can handle rooms as large as 500 square feet. Although there are other factors involved including room height, climate, window size and placement and insulation, in general it takes 25 to 30 BTUs to cool every square foot.
Pros and Cons of Different BTU Levels
The most obvious advantage of a higher BTU level from a portable air conditioner is that it is able to cool a larger space. Conversely, the main disadvantage is that the more powerful models consume more power. More BTUs per hour means more kilowatt-hours consumed, directly influencing your electric bill.
Low Power Models: 5,000-8,000 BTUs
Portable AC units generating between 5,000 and 8,000 BTUs per hour work best when used to cool small rooms or to condition a space for a short amount of time. Any room larger than 250 square feet will not be adequately cooled by units this size. Low-power portable units may also be used to supplement central systems in the event they do not reach the whole house.
Medium Power Models: 8,000-11,000 BTUs
In this range, portable air conditioners are capable of cooling medium-size rooms and may even distribute cool air over the better part of an entire floor. Rooms between 250 and 350 square feet are suitably covered by medium-power portable air conditioners.
High Power Models: 11,000-14,000 BTUs
Getting up to the high-powered models, portable air conditioners in this range of power can reach rooms up to 500 square feet. Under ideal circumstance including proper insulation, low ceilings and thermal windows, a 14,000 BTU portable AC unit may be able to cool a space as large as 700 square feet.
The biggest problem with portable air conditioners with a high BTU output is energy efficiency. They consume a lot of electricity while only cooling a single room. One way to get the most out of your portable AC unit without constantly using the compressor (cooler) is to use the programmable timer and/or energy saver option found on many units. This automatically alternative between fan-only use and cooling settings to maintain a desired temperature without always relying on the cooling power.
BTUs indicate the power capacity of a portable air conditioner. The number should correspond with the size of room you have to cool for maximum efficiency.