Evaporative coolers, also known as swamp coolers, are portable, effective, and eco-friendly cooling solutions. If you're considering purchasing an indoor swamp cooler or one for outdoor spaces, we can help.
See our most frequently asked questions about using a portable evaporative air cooler below:
- How do portable evaporative coolers work?
- Are evaporative coolers only effective in dry climates?
- Will an indoor swamp cooler cool as well as an air conditioner?
- Does adding ice make a swamp cooler work better?
- How do I determine what size swamp cooler I need?
- Why are swamp coolers more efficient & eco-friendly than ACs?
- Will a swamp cooler make everything in my room damp?
- Can you run a swamp cooler all day?
- How long should I run the pump on my swamp cooler?
- How do I clean my swamp cooler?
- At what humidity level do swamp coolers stop working?
- Where else can I use swamp coolers?
How do portable evaporative coolers work?
Evaporative coolers have very few components: They use a fan, cooling media, and water to keep you cool. With the natural power of evaporation, they can effectively reduce the temperature by 25 degrees F. Here's how they do it:
- Warm air is pulled into the unit
- An internal pump moves water from the reservoir over the rigid cooling media.
- The fan pushes air out through the saturated media, adding moisture, effectively cooling down your skin.
Are evaporative coolers only effective in dry climates?
Evaporative coolers can be used in outdoor or semi-outdoor areas (like garages, porches, and backyards) anywhere in the country, even if you live in humid conditions.
Swamp coolers, however, add moisture to the air as they cool. Don't use them indoors if you live in a typically humid climate. Adding more humidity can make your space feel clammy despite the cool air you're adding.
This map shows where evaporative coolers should be used indoors in the USA. They can be used anywhere when placed outside on patios, covered porches, or in garages.
Note: A fresh air source is required when using swamp coolers indoors (even in dry areas of the country).
Will an evaporative cooler reduce temperature as well as an AC?
Evaporative coolers don't chill the air like an AC. The effect of moist airflow hitting a person's skin cools them down. They can effectively replace air conditioners in certain situations, like single rooms in dry climates, covered outdoor spaces, and many outdoor areas.
If you're looking for a system you can set your ideal temperature and the unit maintains it automatically, you should consider a window AC or portable AC.
Does adding ice make a swamp cooler work better?
This is more of a popular myth than a fact. Evaporation simply doesn't work that way. While the ice may initially cool the air blowing over it for a few minutes, the "lake effect" doesn't make the evaporated air cold enough to feel the difference. It's the moist air on your skin that cools you down. A thermometer may register a difference of 2 degrees at most over about 30 minutes. On a hot day, the ice will melt quickly; however, you can safely add it to your evaporative cooler if you want to.
How do I determine what size swamp cooler I need?
When choosing a size, it's helpful to calculate the ideal CFM, or cubic feet of airflow per minute, that an evaporative swamp cooler should have to cool your room optimally.
CFM is essentially the amount of fresh air that is cycled through and cooled every minute. If you know the size of your space, use the quick links below to find the right evaporative cooler for your space:
- Small rooms under 500 square feet
- Medium-sized spaces up to 1,000 square feet
- Large Commercial & Industrial Spaces
For more information on choosing the right size, take a look at our Evaporative Swamp Cooler Buying Guide.
Why are evaporative coolers more efficient & eco-friendly than ACs?
They don't use energy-heavy compressors or harmful, toxic refrigerants to facilitate cooling. An AC compressor, not the fan, is the major energy user and the main reason for your high cooling bill.
In certain scenarios, cooling with a swamp cooler can cost up to 50% less than a traditional air conditioner because you use less energy.
Will a swamp cooler make everything in my room damp?
No. The keyword in their cooling process is 'evaporation', so they will not make the contents of your room wet or leave you feeling damp. That said, if it is operating in a small room without a fresh air source, the air will eventually become more and more saturated, and it will begin to feel clammy to your skin.
As dry air moves through the swamp cooler, it absorbs moisture from the saturated cooling pad before being released. This process evaporates the tiniest of water droplets into the air, so the air is invisibly moisturized and cooled.
How often will I need to refill my evaporative swamp cooler?
This really depends on how often you use your cooler and the operating speed used. Running your cooler all day at the highest speed, for example, will use more water. You may have to fill it a few times a day in this scenario.
Consider an evaporative cooler with continuous fill for less maintenance. These units feature a hose connection for continuous use without having to refill the water tank.
How long should I run the pump on my evaporative cooler?
You will want to run the pump only for as long as you have water in the reservoir. Running the pump without water will overheat the pump, causing it to burn out. Most models have an alarm that alerts the operator when the reservoir is empty.
Many evaporative coolers can be operated using the fan alone and either have a specific operating mode or a pump on/off switch, which can be used to turn off the pump. This allows the cooler to be used as a high CFM air circulator, which is sometimes just what you need.
How do I clean my evaporative cooler?
Like humidifiers, it's important to clean your swamp cooler's water reservoir or water pan regularly. As a rule of thumb, drain your swamp cooler once a week to prevent fungus or mildew growth. For more information, see this article that includes a video on cleaning your swamp cooler.
Other Tips
- Clean the reservoir and let it dry before closing it up or putting it back in the swamp cooler.
- You should also clean and/or replace cooling media based on the manufacturer's recommended timeline for hygienic and efficient operation.
- Store evaporative coolers in dry spaces and cover them during the off season if possible.
At what humidity level do swamp coolers stop working?
Evaporative swamp coolers are most effective when the humidity level is 50% or lower, especially for indoor use. Because they add moisture to the air, they are less effective when humidity levels are high, even when used outside.
This doesn't mean they can't be used in more humid climates outdoors. They do provide high airflow, higher than that most fans can achieve, which makes them effective air circulators. Just be sure the model you are considering can be used as a fan only.
Where else can I use a swamp cooler?
While evaporative swamp coolers may be visualized on decks or poolside, they can be used effectively indoors in very dry climates. In fact, there are window-mount coolers that are large enough to cool a whole house.
Additional residential spaces where they're effective include garages, workshops, and other work areas. Smaller units can be carried in an RV or camper.
Swamp coolers are also very effective at outdoor events and sports venues, for use in barns, stables, and dog kennels, as well as restaurant outdoor dining spaces.
In Summary
Evaporative swamp coolers are an earth-friendly and economical way to handle the heat of summer. Exceptionally effective in dry climates, such as the US Southwest, they can be used in almost any climate, either in their evaporative mode or as a powerful air circulator. With sizes from 175 CFM all the way to 11,000 CFM, these machines can be used in both residential and commercial & industrial spaces.
Still Have Questions?
We know choosing an evaporative cooler isn't an easy decision. To learn more about these versatile machines, visit our Evaporative Swamp Cooler Knowledge Center.
Not sure what's best for you? We can take the guesswork out of decision-making. Call us at 1-800-934-919. We want to help make your indoor space healthy and comfortable.
