Outdoor Swamp Cooler Features


A Swamp Cooler’s Features Can Make it Perfect for Outdoor Use

Swamp coolers, also known as “air coolers” or “desert coolers,” are a kind of evaporative cooler — simple devices that push air through water-soaked pads to provide cooling in hot, dry conditions. They are usually used indoors but can work especially well outdoors because they need some fresh air in the area they cool in order to be most effective.

Features to look for that make a swamp cooler especially suited to outdoor use optimize their portability. Features that increase their efficiency also reduce costs to run.

Outdoor Swamp Cooler Features: Increased Portability

Access to water and electricity can limit the outdoor usefulness of any swamp cooler. But tanks and batteries or generators help you handle that with ease. Sturdy casters or dollys can simplify moving air coolers from your vehicle to an event area.

Water Supply

Swamp coolers with tanks are the most portable and generally hold enough water to last for a few hours of mild weather. Keep in mind that hotter, drier weather will use more water per hour. Be prepared to refill the tank as necessary. You may need to have an extra supply of water handy. Separate, portable tanks of up to 50 gallons / 190 liters and more are easily available and come with wheeled frames for portability.

Units of about 100 watts and about 500 CFM, which can cool a 10′ x 10′ x 10′ tent average less than 1 gallon (4 liters) per hour. Larger units may use as much as 20 gallons (75 liters) per hour or more. Actual water use depends on the heat and humidity levels of the area being cooled.

Some swamp coolers have an optional hose / tank set-up. If you’ll be where a hose cannot reach, these can attach to a portable tank or reservoir instead, making them more portable but still convenient if you have access to running water.

Easier to Use – Water Level Sensor

This swamp cooler feature senses when the water level in a tank is low and alerts you with a sound or light that it’s time to refill the tank. Because water use varies so much depending on heat and humidity, this can be a more reliable feature than a timer.

Learn how much water your swamp cooler will need.

The least portable but most convenient are swamp coolers that connect to water lines providing a continuous supply of water. These units can shut off the water as needed.

Electricity Supply

An add-on battery or a generator – whether gas or solar-powered – would make a tank-fed swamp cooler usable almost anywhere. Swamp coolers with integrated batteries are available for cooling smaller, personal-sized areas.

Easier to Use – Power Supply Options

Some swamp coolers are built to accept multiple sources of electricity. Solar/AC/DC Plug-in options mean you can use these units anywhere, including your car, camper, boat, tent, park, beach, etc.


Portable swamp coolers are mounted on casters so they can be wheeled from place to place. Heavier units will have wider casters. The wider the caster the easier it will be to move the unit over uneven ground, such as dirt or grass. Look for casters with locking wheels. You might want to use a separate wheeled frame or dolly to move units across uneven ground.

Outdoor Swamp Cooler Features: Increased Efficiency


Swamp coolers used outdoors are exposed to more dust and debris than coolers used indoors. Filters extend the life of the pads by reducing the amount of particles that can clog or damage them. Filters for outdoor use work harder and collect particles faster than for indoor air coolers. So, you’ll need to replace them more often than you would for indoor use. Inspect your unit’s filters from time to time. Clean or replace them when they start to get clogged since clogged filters can lower the cooling capacity of your unit.

  • Carbon filters help eliminate odors.
  • HEPA filters help filter out particles from the air such as dust, pollen, and pet dander (these can be especially helpful for asthma and allergy sufferers).

The fan-only option increases the usefulness of a swamp cooler

Using the fan-only feature can provide cooling throughout the day. Evaporation cooling is less effective when humidity levels are high – usually in the mornings and later afternoon / evenings. But using the fan alone can provide cooling of up to 4 – 8°F / 2 – 4.5°C, even when the humidity is high. The evaporation function can be turned on as the air gets dryer and hotter midday when it will be more effective.

This option saves you water and energy costs, and reduces the use of the pads, meaning less maintenance and cost for those, as well.

Pre-cool Features

This setting lets the water run before the fan turns on. If the fan starts at the same time as the water pump, the fan will start blowing ambient temperature air before the pads have a chance to fill with water. But with this setting, the pads fill with water first. Then when the fan starts, the air from the unit will be cool immediately.

Note that if you are running a fan-only feature before turning on the evaporation function, it will take a few minutes for the pads to fill with water before the temperature drops from evaporation.

Air Flow Direction

Being able to adjust the direction of the swamp cooler’s airflow can help you place the cool air exactly where you need it. If people tend to gather around a certain part of the area you are cooling, perhaps a table or seating area, adjustable louvers can help you direct the main flow of cool air toward that area without moving the cooler.

Ducting adapters can be installed onto some units for the same purpose.

Some swamp coolers have an oscillating feature, which means they swivel back and forth to cool a larger area. This changes the direction of the airflow. Even though the amount of airflow doesn’t change, it moves, intermittently covering more area than if it were still.

Learn how much airflow you’ll need from your swamp cooler.

Air Flow Speeds

Multiple speeds can help you fine-tune your cooling and energy use. Low speeds are great for days with milder weather or at night. Low speeds use less electricity and water than high speeds, sometimes saving over 50%. Low speeds are also quieter — better for sleeping and other activities that may require especially quiet environments.

Use high speeds during the hottest hours of the day or when you need to quickly lower the temperature, such as when the unit has been off for several hours.

Thermostat and Timer

A thermostat control can turn the cooler on when the area you want to cool reaches a certain temperature. It can also be set to turn off when the area cools down to a certain temperature.

A timer control turns the unit on and off automatically at certain times rather than at certain temperatures. Both the thermostat and timer can save energy by limiting your cooler’s use to when you need it most.

Cabinet Shape and Color

Because cool air is heavier than warm air, the cool air from your swamp cooler tends to flow downward. For that reason, consider cabinets with outflow vents near the top of the unit. If this is not an option, you may be able to direct the airflow upward with adjustable louvers.

Swamp coolers can get really large — 3 feet / 1 meter vertically and horizontally is not unusual. After all, they contain the workings to move a lot of air and hold many gallons of water. A simple thing like color options can help it either blend in with its environment or emphasize its technical and functional appearance.

Water Purge or Flush sensor helps with swamp cooler maintenance

An automatic “water purge” or “flush” control works together with a drain valve to periodically remove the recirculating water from the system and replace it with fresh water. This valuable swamp cooler feature can prolong the life of your cooler and help keep it clean.

Noise Level

Most swamp coolers run fairly quietly. Their pumps and motors aren’t very large and they don’t use a lot of electricity. But some are built to run more quietly than others. And if you need yours to be especially quiet — if you’ll be running it when people are sleeping, for example — the noise level may be important to you.

Some manufacturers use a decibel rating (dB) to give you an idea of the amount of noise you can expect from their cooler. But there are a lot of variables involved with how a cooler makes noise.

The noise from a swamp cooler can be made by many things: the motor spinning, the motor’s own cooling fan inside the enclosure, the fan blades moving, the pump operating, and the water trickling through the unit. Running a cooler on a low setting or with the fan only will be quieter than the same fan running on high with evaporation.

Even the way it’s installed can make it louder or quieter, which is something a manufacturer cannot predict. A unit installed on packed earth or solid rock may make less noise than a unit installed on a raised metal platform.

Consider the quality of the cooler’s sound as well as its volume. Different frequencies produce different tones, even at the same decibel level. A loud, low rumbling sound may not be as noticeable as a quiet, high whistling sound.

So just use dB ratings to get a general idea of the fan’s noise level.

Here’s a chart of decibel ratings and the typical sound they compare with.

Bottom threshold of human hearing10dB
Recording studio20dB
Quiet living room30dB
Quiet office or library, refrigerator40dB
Quiet conversation50dB
Average office noise, clothes dryer60dB
Average conversation, dishwasher70dB
Average factory80dB
Typical home music volume90dB
Heavy truck100dB
Decibel levels and examples

Other Outdoor Cooling Methods

Swamp coolers combine two of the most effective outdoor cooling methods. But, as mentioned above, they have some limitations. You can maximize their cooling by combining them with other methods or devices, or other options may be more effective.

Take a look at our comparison page or our pages on other outdoor cooling methods:

  • Outdoor fans combine well with swamp coolers, ensuring adequate air flow and distributing the cool air from evaporation.
  • Misting fans are another kind of device that combines evaporation and wind chill to cool outdoor areas.
  • Outdoor shades are a nearly universal solution that work well with any outdoor cooling method, including swamp coolers.
  • Misting systems use a similar technology as swamp cooler, but in an open system that can cool larger areas.
  • Portable air conditioners are especially suited to enclosed areas (tents, sheds, etc.) and special circumstances.