What is a Portable Air Conditioner?
Portable Air Conditioners (PACs) are increasingly becoming one of the most popular forms of home air cooling. PACs are simply standard air conditioning units that are designed to extract heat from an area via a refrigeration cycle. They are placed on wheels, meaning they can be easily moved from location to location, which makes them ideal for spot cooling individual rooms or cooling areas normally unsuitable to standard window air conditioning models. It is highly recommended that you use PACs in conjunction with central air conditioning for an efficient means of supplemental cooling for areas that may have an extra heat load (such as a sunlit room) or rooms that are poorly vented. Though these units have exhaust tubes that must be vented, they are truly portable in the sense that they require no permanent installation.
Most PACs come with a window venting kit, which easily slides into almost any window. The exhaust hose is easily fit into the appropriate space in the window kit, and the unit is ready to go. PACs consist of one “box” that holds both the hot and cold side of the air conditioner in one and they use the exhaust hose to expel heat. For condensing air conditioners, there are several ways to get rid of the water that the air conditioner condenses out of the air. Some units collect this water in an internal drain bucket, which requires the owner to occasionally drain the unit manually, install a pump to push condensate water out through a tube in the drain hose, or adapt for direct drain off. However, the newer models produce no excess water at all, evaporating the condensate water automatically through the hot air expulsion hose.
How They Work
Portable air conditioners operate through a fairly simple process. Warm air from the surrounding area is drawn in through special inlets on the portable air conditioner unit. This air is circulated through the unit and is cooled by evaporator coils that have refrigerant running through them, and then the air is blown out through the front. Remaining hot air that was drawn through the unit is expelled and vented through the back with an exhaust hose.
Through this process, air is continually “cycled” in such a way where warm air in the area is continually drawn through the portable air conditioner unit and replaced with cooler air. This means that the room is consistantly cooled until it reaches the desired temperature setting.
Types of Portable Air Conditioner Units
Residential PACs are generally used for cooling homes, apartments, and smaller areas up to 500-525 square feet, and they range between 5,000-14,000 BTU. These models are a single hosed units, meaning they have one hose running from the back of the portable air conditioner to the vent kit (more information about vent kits found below), where hot air can be expelled. As a note, exhaust hoses are required to vent a portable air conditioner. Residential PACs generally require the use of only a single hose since BTU requirements are smaller and creation of negative air pressure is not a factor when in use.
Commercial portable air conditioners generally use a double hose design, which provides more cooling power for large areas and a cooling BTU of over 14,000. In this double hose design, one hose is designated as the exhaust to vent hot air, while the second hose is used as an intake to draw in additional air (usually from the outside). This additional intake hose is required to help draw in extra air needed to offset “negative air pressure” in the area being cooled. Higher BTU units cycle airflow in larger amounts to expel hot air at a much faster rate, which creates a negative air pressure in the room. The solution is to have an intake hose bring in additional air to stabilize this negative air pressure.
Heat and Cool Units
A heat and cool portable air conditioner is a unit that provides both cooling and heating options. The heating function works by reversing the normal process of how PACs cool. Instead of expelling hot air and blowing cool air out, heat/cool PACs expel cool air and blow out warm air. Of note, heat and cool portable air conditioning units are not meant to be designated heaters and should not be used in environments where the ambient temperature falls below 50°F.
Units with Dehumidifier Functionality
Some portable air conditioners have a special “dehumidifier” mode. While almost all PACs expel some moisture from the air through the exhaust hose, a few have a dehumidifier mode and can act as designated dehumidifiers. While turned on, these portable air conditioners cool as normal but also expel quite a bit of moisture through the exhaust hose.
Portable Air Conditioner Accessories
Like central air conditioners, PACs have replaceable filters that clean the air as it is being drawn through the unit. The replaceable activated carbon filters usually last for three (3) months and should be replaced routinely.
Portable air conditioners are primarily vented through a window kit to the outside. Included with almost all PAC units, a window vent kit usually consists of a window plate and an adapter for the plate. The adapter is used to fit the hose into the window plate which is then set into the window frame. Note that window vent kits are designed for use in vertical and horizontal sliding windows.
In instances where venting through a window is not possible, consider other options like venting through a drop-ceiling or subfloor.
One of the biggest advantages of using a PAC is the ability to cool a specific area in the home because these units have caster wheels that allow them to be easily moved from room to room. While central air conditioning cools all rooms evenly, portable air conditioners can provide more cooling for the warmest areas or even act as a suitable replacement for central air conditioning. By not having to turn down the thermostat to comfortably cool all living areas, one can save a considerable amount on energy and electricity.
Choosing the Right Portable Air Conditioner
If you've decided a portable air conditioner is the choice for you, here are some important considerations:
- Your BTU Requirements: This is probably the first and most important consideration. Unlike other air conditioners, PACs are designed to move around the house from room to room with ease. This means that you should try to get the most appropriately-sized air conditioner for the room that you will be using the PAC in, but be mindful of all the uses that you will need the unit for when you try to estimate your required capacity. For one-room applications, you ideally want to get a unit with a capacity as closely matched to your needs as possible. When determining BTU requirements, the two most important factors are room size (in square feet) and heat load. Heat sources that can affect the heat load are sources such as cooking appliances, sunlit windows, electronic devices, etc.; and factors such as room humidity, ceiling height, insulation and more can also play a role. The chart below can help you to determine the BTU requirements you may need for your space:
- Your Drainage Requirements: Do you want a unit that can be drained continuously? Do you mind emptying a drainage bucket a few times a day? Are you willing to pay more for a unit that exhausts the condensate water through its exhaust hose so you don't have to worry about drainage at all? These are common questions you should ask yourself about using a PAC.
- Your Venting Needs: Though most units have 5 inch diameter exhaust hoses, some units have 3 ½ inch exhaust hoses. Note that exhaust hose lengths and window venting kit sizes differ as well.
- The Unit’s Energy Efficiency and Energy Requirements: You should be mindful of the EER of the air conditioner that you choose. A higher EER is better and often costs less in the long run than a less-efficient unit. Most PACs run on a standard 120-volt socket.
Once you've decided on the above factors, you’ll want to think about other features that can add to the convenience of your future portable air conditioner:
- Air Filtration: All models come complete with an air filter, and better models have filters that can clean your air during operation.
- Remote Control: Remote controls come with remote controls to control the unit from across the room.
- Manual vs. Electronic Controls: Manual models can be simpler to use and they often offer superior timers to electronic models, but electronic models usually offer more advanced features.
- Noise Level: Though many of today's air conditioners are quieter than older models, you still might want to consider their noise level. Noise levels are often given in decibel (dB) ratings. The higher the decibel level, the louder the unit is; every 10 decibel increase is an increase in the sound pressure by a factor of ten (for example, 60 Decibels is 10 times louder than 50 Decibels and 100 times louder than 40 Decibels).
- Timer and Sleep Function: Timers allow you to save energy by running the air conditioner at set times. For example, you might set the air conditioner to run when you anticipate being at home, which helps you to not waste energy by cooling your room when no one is there. Sleep timers also help to save energy by cooling less after the air conditioner has been running for a set time. This way, you set the air conditioner to run while you are going to sleep and it continues running while you sleep, but at a lower level (i.e., the temperature in the room is allowed to rise a bit) while you sleep.
- Air Output: Almost all models have at least two different settings for airflow. You might want more settings to increase the versatility of cooling. Also pay attention to the Cubic Feet per Minute (CFM) rating, which is a measure of the volume of air blown. The higher the CFM, the more airflow the unit kicks out.
- Heating Options: Some portable air conditioners can heat as well as cool. This can be useful in the winter time, enabling you to use your air conditioner year-round.
- Louver Adjustability: The more ways you can adjust the louvers (up/down, side-to-side), the more options you have for directing airflow. Also, some unit’s louvers can be set to the swing setting, so they blow out cool air from several different positions.
- Air Conditioner Physical Size and Appearance: Some air conditioners are smaller and/or more pleasing to the eye than others.
Quick Window Installation
Portable air conditioners come with installation instructions and kits for installation into windows. You should first follow the installation instructions that come with your PAC, but here are a few additional tips for what a standard installation might entail.
PACs can be installed in many places that conventional air conditioners cannot, which is one of the main advantages of portable air conditioners. However, the easiest installation is into a standard sliding window. Due to the design of the venting kit, it is equally easy to install one of these units into a standard double-hung window or a side-to-side slider window
- Position the portable air conditioner near the window.
- Connect the exhaust hose to the rear of the air conditioner.
- Connect the other end of the exhaust hose to the window venting kit.
- Open your window and place the window venting kit in the window; adjust its length, if necessary. Close the window on the venting kit
- Close the window on the venting kit, plug in the PAC, and turn it on.
That's all there is to a simple window installation!