Portable Air Conditioner
Types, Capacity, Features
TYPES OF PORTABLE AIR CONDITIONERS
Air Cooled
Most portable air conditioners are air cooled. These are the most common type and are available in the widest range of products and options. They use air vents / hoses to remove the heat from the cooled area. Their set-up is quicker than water-cooled types and they only need electricty to operate. They are larger than water-cooled models, though, and are not as energy-efficient.
Water Cooled
Water cooled air conditioners use water lines to remove the heat from a cooled area. They need a water supply as well as electrical supply, making their set-up more involved. But they are smaller than air cooled types and are more energy efficient. Their initial cost may be higher than air cooled air conditioners, but the savings in energy expenses can offset that over time.
Single Hose
Smaller units use only one vent hose. Warm air from the area to be cooled is drawn directly into the air conditioner. Some of that air is used to operate the unit and the rest is sent through the hose away from the area.
Double Hose
Larger, more powerful units use a double hose system because they handle more air flow than the single hose of smaller units can handle. One hose directs warm air away from the area being cooled, the other hose pulls in extra air to operate the unit. You'll need to have two openings in your area for these two hoses.
HOW MUCH COOLING CAPACITY?
Size of Area
The first thing you'll need to know is approximately the size of the area you want to cool. This will tell you about how much cooling capacity you'll need from a portable air conditioner. If you have more than one area that needs to be cooled, consider whether one unit can be moved to cool each area, or if you'll need multiple units. One large unit can usually be set up to cool several small areas at the same time.
BTUs (British Thermal Units) are a common way to measure the cooling capacity of air conditioners. It's often simpler to call it the "size" of the air conditioner, instead of "how many BTUs" or "how much cooling capacity". Follow the chart here to get a general estimate of the "size" portable air conditioner you'll need to cool a certain sized area.
| AREA TO BE COOLED | CAPACITY NEEDED | |
| Square Feet | Square Meters | BTUs per hour |
| 100 to 150 | 9.3 to 14.0 | 5,000 |
| 150 to 250 | 14.0 to 23.3 | 6,000 |
| 250 to 300 | 23.3 to 27.9 | 7,000 |
| 300 to 350 | 27.9 to 32.5 | 8,000 |
| 350 to 400 | 32.5 to 37.2 | 9,000 |
| 400 to 450 | 37.2 to 41.8 | 10,000 |
| 450 to 550 | 41.8 to 51.1 | 12,000* |
| 550 to 700 | 51.1 to 65.0 | 14,000 |
| 700 to 1,000 | 65.0 to 92.9 | 18,000 |
| 1,000 to 1,200 | 92.9 to 111.5 | 21,000 |
| 1,200 to 1,400 | 111.5 to 130.1 | 23,000 |
| 1,400 to 1,500 | 130.1 to 139.4 | 24,000* |
| 1,500 to 2,000 | 139.4 to 185.8 | 30,000 |
| 2,000 to 2,500 | 185.8 to 232.3 | 34,000 |
* In the world of air conditioning, multiples of 12,000 BTUs are commonly referred to as a "ton." This does not mean the air conditioner weighs 1 ton! A "1 ton" air conditioner may only weight 150 pounds / 68 kg.
A 12,000 BTU portable air conditioner is called a "1 ton air conditioner." A 24,000 BTU portable air conditioner is called a "2 ton" unit. A 36,000 BTU portable air conditioner is called a "3 ton" unit, etc. Sizes over 5 tons (60,000 BTU) are called "mobile" air conditioners.
Note that different manufacturers will have different charts with different recommendations of BTUs for different sized areas. This is because the best size for your area depends on a lot of different factors. Varying charts base their recommendations on different criteria. This emphasizes the fact that your cooling needs are fairly unique.
- Some of the variables to consider:
- Depending on outdoor air temperature and humidity, you may need to increase the BTUs by up to 40%. It takes more BTUs to cool a hotter space than a cooler one.
- If more than two people will regularly be in the space, add 600 BTUs per person. Bodies add warmth to an area and more BTUs will be needed to cool an area with more people in it.
- Materials and insulation of the enclosed space will affect the efficiency of any portable air conditioner. For example, a tent with tightly woven canvas or nylon panels would maintain the cool temperature better than a tent with mesh panels that would allow more of the cool air to escape. A trailer might have more insulation in the walls than a shed, and would maintain the cool temperature better than the shed would. You can counter poor insulation somewhat by placing the unit closer to the spots that need the most cooling.
When you purchase or rent a portable air conditioner, tell your sales or rental consultant the conditions of the area you'll be cooling. This will help them advise you on the best sized unit for your needs.
FEATURES AND OPTIONS
Portability
Smaller portable air conditioners may be equipped with casters that make easy work of moving them around small flat areas. The smallest of these usually have lighter duty casters than the larger units. Unless it has casters you'll need a dolly handy for the heavier units, especially if you'll be taking them a distance -- say, across a parking lot or field. The biggest of these -- over 60,000 BTUs -- can weigh several hundred pounds and would require a trailer or truck to move them around. They can be permanently mounted so a trailer can be towed in and out of an area without having to unload and load the air conditioner every time you use it.
Programmable control panels can help you save energy while keeping your area cool and comfortable. If you know you'll need your area cooled at certain hours, certain temperatures, simply program that it. This can save energy and costs by running your portable air conditioner only when you need it.
Some units will have a knob or button with a general indication of temperature. Digital thermostats can control the target cooling range more precisely and can maintain that range more consistently.
Remote control is especially helpful if your portable air conditioner is outdoors or hard to reach. Some units use only remote control -- no controls are actually on the unit. Remote controls are available in hand-held styles or wall mount styles.
Multiple fan speeds can be tremendously helpful in perfecting the cooling of an area. Especially for outdoor cooling, selecting the best size unit can be a little challenging. Add to that temperature fluctuations caused by the weather and time of day, among other things. Being able to simple raise or lower the fan speed can help you deal with these challenges in a simple way. Also, lower fan speeds run more quietly than higher speeds.
One of the advantages of using portable air conditioners for outdoor cooling is that they lower the humidity of an area. Many can be set to dehumidify only, meaning that even with the cooling function off they can work to dehumidify your area. Humidity can be a problem during wet seasons. Lower humidity levels can ease allergies, stop condensation and mold growth. This can make your portable air conditioner invaluable year-round.
A heating option is another feature that can make a portable air conditioner useful all year. These units can use a lot of electricity and generate a lot of heat simply to operate. By turning off the cooling function, a portable air conditioner can heat a room even more easily than it can cool it.
Air filtering
Portable air conditioners filter the air of a space as part of the way they cool it. By turning off the cooling function, the fans will still blow air through the filters, allowing air filtering without the cost of running the cooling. Special filters are available for some models to remove pollen, bacteria, animal dander and dust, making them especially helpful for people with allergies.
Since all portable air conditioners need to be vented, they almost all come with some sort of venting system. This helps you fit the hose(s) through a window or other opening, with a fitted piece to hold the hose and cover any gaps around it. Venting system options may include different fittings and insulation to close any gaps around the hoses leading into or out of an area.
Adjustable Air Vents may be as simple as adjustable louvers / shutters that can be nudged to shift the air flow. These work like the adjustable air vents on a car's air conditioning system. Surprisingly, not all portable air conditioners have this feature. Others may have air nozzles that can be rotated or extended to really direct the air where you need it.
Handling Condensation
Air conditioners remove humidity (water) as well as heat from the air. Simpler units have a tank that collects the water. The tank needs to be drained occasionally to keep it from overflowing.
A step up from this is a Gravity Drain -- a simple hose attached to the tank that lets the water drain onto the ground away from the area being cooled and away from the portable air conditioner.
A Condensate Pump is sometimes used with the drain to move the water up over a wall or through an opening in the structure.
Self-Evaporating units evaporate the water into the hot air exhaust hose. These units require little if any draining of the tank.
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