How do portable air conditioners work?  
  
Cooling your entire room with portable air conditioners is as easy as taking the warm air and cooling it. Through a tube connected to the window the unit circulates warm air outside. A lot of units help to maintain an appropriate humidity level, as explained by Shirley Hood, an appliance sales specialist at the appliance retailer ABT. Users then adjust things like the speed of their fans and temperatures.  
  
  
  
Hood explained that a lot of people utilize them to set the units in rooms with windows and floor space. "They're easy to utilize. In general, they're utilized in offices."  
  
  
  
portable ac for room air conditioners are more expensive alternative to window units however, they're much simpler to install and usually smaller, meaning it's possible to move them from room to room with too much effort, said John McKeon, MD, the CEO of Allergy Standards -- an organization that is able to verify that products are "asthma and allergy-friendly" among other things.  
  
  
  
Examine your room first. BTUs are a measure of the cooling power of your air conditioner. BTUs are a measure of the efficiency of the air conditioner is at cooling your space. McKeon declared that an average air conditioner needs 20 BTUs per square foot to cool. It's essential to select the most efficient model for your space, but be aware that having more BTUs aren't always the best option.  
  
  
  
EnergyStar is a federal program promoting energy-efficient products, has its own guidelines to help you select the best model. The weight and size of the model will increase with an increase in BTU capacity.  
  
  
  
Cooling 250 square. feet 500 sq. feet: 5,000 to 6000 BTUs  
  
Between 250 and 350 square feet: 7,000 - 8000 BTUs  
  
Between 350 and 450 sq. feet From 9,000 to 10,000 BTUs  
  
12,000 BTUs: 450 - 550 sq. feet  
  
  
  
Marla Mock, VP Operations for HVAC services firm Aire Serv previously stated to NBC News Shopping that an undersized air conditioner could create issues with cooling during hot days. "But should you choose to purchase an excessively large AC unit, it'll reach the desired temperature too quickly and cause rapid breakdown and short-cycling."