Is the heat making you hotter than a jalapeño pepper? Then you may be reaching for a trusty portable evaporative cooler.
But does portable evaporative cooling work?
Portable evaporative cooling works by using water evaporation to naturally cool hot, dry air. Evaporative cooling works better in less humid climates and in smaller spaces with good airflow. Portable evaporative cooling is energy efficient, convenient, quiet, and easy.
In this guide, you’ll learn why and how portable evaporative cooling works, when to use it, and alternatives for humid climates.
Why Portable Evaporative Cooling Works
Evaporative cooling is an effective way to cool indoor spaces, especially in dry climates.
Portable evaporative coolers, also known as swamp coolers, offer many benefits that make them a good cooling solution in the right conditions.
Here are 10 reasons why portable evaporative cooling works:
- Lower humidity allows for better evaporation – Evaporative coolers work best when humidity is low, below 60%. In dry climates, water can evaporate efficiently into the air.
- Cools through water evaporation – As the water evaporates, heat is removed from the air, dropping the temperature. This natural process provides cool air without chemicals.
- Adds moisture to dry air – The evaporation process also humidifies the air, which is beneficial in dry environments.
- Energy efficient – Portable evaporative coolers use less energy than traditional air conditioners. The water pump and fan use minimal electricity.
- Cost effective – Swamp coolers have simple designs with few moving parts. This makes them an affordable cooling option compared to AC units.
- Portable flexibility – Compact portable designs with wheels allow you to move the cooler between rooms or outdoors.
- Ventilation – The fan and water-soaked pads facilitate air exchange, circulating fresh air through your space.
- Easy to use – Just pour water in the tank, plug it in and turn it on. Minimal setup or maintenance required.
- Safer air quality – Evaporative cooling adds no chemicals or refrigerants to the air, improving indoor air quality.
- Quieter operation – With only a fan and pump, portable swamp coolers are quieter than air conditioner units.
How Portable Evaporative Cooling Works
Portable evaporative coolers provide cooling through the natural process of water evaporation.
The basic components are a water tank, pump, cooling pads and a fan.
The pump moves water from the tank onto the cooling pads, which are made of porous wood or synthetic fibers. The wet pads provide a large surface area for evaporation.
The fan draws hot dry air from the room through the damp cooling pads.
As the air passes the pads, the water evaporates removing heat from the air. This cooled air is then blown out into the room.
More water is continuously pumped to the pads from the tank to sustain the evaporation process.
The constant water movement and evaporation cools and humidifies the indoor air without chemicals or compressors.
Check out this video on how evaporative cooling works:
How Effective are Portable Evaporative Coolers?
In optimal low humidity conditions, portable evaporative coolers can effectively reduce air temperatures by 15-30°F.
A powerful 1,500 CFM cooler running at full capacity with proper airflow can cool up to 650 square feet.
Smaller units around 2-3 ton capacity can lower indoor temps by around 20 degrees.
Effectiveness depends on your climate, the size of space being cooled, and the cooler’s airflow rating.
Portable evaporative coolers may not be as effective for larger areas over 650 sq ft. Multiple coolers can be used to increase cooling capacity.
Do Portable Evaporative Coolers Work in 100 Degree Weather?
Yes, portable evaporative coolers can be very effective at cooling indoor spaces when outdoor temps are 100°F or hotter.
At least, provided the humidity is low.
The greater the temperature difference between the hot outside air and the cooler inside air, the more cooling the evaporative cooler can provide.
At 100°F with less than 30% humidity, a portable swamp cooler can potentially lower indoor temperatures by 20-30°F.
The hot dry air entering the cooler allows maximum evaporation as it passes through the wet pads. Just be sure to have adequate airflow from open windows.
Are Portable Evaporative Coolers Better Than Fans?
Portable evaporative coolers are generally more effective at cooling than fans.
Evaporative coolers lower air temperature through water evaporation whereas fans simply circulate existing air without cooling it.
However, fans use less energy and do not add humidity to the air.
In humid climates above 60% RH, fans may be a better option.
Portable fans also work well to complement evaporative coolers by optimizing air circulation.
How Can I Make My Portable Evaporative Cooler Work Better?
Here are a few ways to make your portable evaporative cooler work even better:
- Keep windows and doors open for airflow
- Position near the window where hot air enters
- Refill water frequently and use cooling pads
- Clean pads and water tank regularly
- Add ice packs to the water tank
- Use a ceiling fan to spread the cool air around
- Cover windows with blinds to block sun
- Lower the humidity with a dehumidifier
- Size the cooler appropriately for the room
Optimizing airflow and ensuring efficient evaporation will get the best performance from a portable evaporative cooler.
Do You Need to Open a Window with a Portable Evaporative Cooler?
Yes, keeping windows open is recommended when running a portable evaporative cooler for maximum effectiveness.
Having open windows allows the cooler to draw in fresh hot dry air from outdoors to pass through the wet pads and be cooled.
This optimizes the cooler’s evaporative capacity.
Exhaust ports on the cooler also work better to vent the humid indoor air outside.
Closing all windows restricts proper airflow and will reduce the unit’s cooling ability significantly.
Does Ice Make Evaporative Coolers Colder?
Yes, adding ice packs or ice cubes directly into an evaporative cooler’s water reservoir can make the air blowing out colder.
As the ice melts, the chilled water cools the pads more.
This provides a boost in cooling capacity, especially when it’s very hot out.
Adding ice also reduces the temperature of the water recirculating over the pads.
Colder wet pads increase the temperature differential, improving evaporation for better cooling. Just avoid overfilling with ice that can block water flow.
Can You Leave Evaporative Coolers on Overnight?
It’s typically recommended to turn evaporative coolers off overnight while sleeping.
Continual moisture released into an enclosed room for hours can lead to excess humidity buildup.
The cooling effect may also diminish overnight when temperatures drop.
However, in very dry climates, running the cooler overnight can be effective.
Use a timer or thermostat to periodically cycle the cooler on and off.
This preserves some of the cooling effect while limiting humidity. Also crack open windows and point cooler vents outside.
5 Good Uses for Portable Evaporative Cooling
Here are 5 great uses for portable swamp coolers:
- Cool workshop or garage spaces up to 650 square feet. The water vapor also catches airborne dust particles.
- Chill patio, garden or outdoor areas. Position the cooler to blow cool air where you want it.
- Use in a bedroom for cooler sleep since it runs quietly. Add water before bedtime.
- Supplement AC to save on electricity bills. Run the cooler on hot days to reduce AC runtime.
- Spot cool the room you’re in without cooling empty rooms. Move it around the house as needed.
When to Use Portable Evaporative Cooling
Evaporative cooling performs best in low-humidity climates below 60% RH.
The dry air allows the water to effectively absorb heat as it evaporates. Portable coolers can lower air temperatures by up to 30°F when conditions are right.
Ideally use evaporative cooling when the outdoor humidity is 40% or lower.
This technology works well in dry Southwestern and Western states like Arizona, Nevada, Utah, New Mexico and Colorado.
Also operate them when outdoor temperatures are 90°F or hotter to maximize cooling capacity.
Position the cooler near an open window so it effectively draws in hot dry air to cool down.
When Not to Use Portable Evaporative Cooling
There are times when evaporative cooling is not effective:
- High humidity climates – Areas with high humidity above 60% will significantly reduce evaporative cooling performance.
- Cooler temperatures – Run the cooler when it’s above 90°F outside for best results.
- Closed indoor spaces – Keep windows open for airflow and so the cooler can draw in dry air.
- Over 500 sq. ft. – Portable evaporative coolers work best in smaller spaces under 650 sq. ft. For larger rooms, use multiple units.
- Not enough water – Check the water level regularly to prevent the cooler from running dry.
Alternatives to Portable Evaporative Cooling
In climates not suitable for evaporative cooling, here are some alternatives:
- Air conditioners – Conventional ACs cool by removing heat and work in all humidity levels. Central air or window units can cool whole houses.
- Fans – Circulate air and provide a cooling breeze without adding humidity. Use ceiling fans or portable fans.
- Dehumidifier – Reduces humidity to allow evaporative cooling or ACs to work better. Also improves comfort.
- Air cooler – Cools air using ice packs without evaporation for enclosed spaces with no ventilation.
- Whole house fan – Draws in cool outside air while venting hot inside air in the evenings when it cools down.
Final Thoughts: Does Portable Evaporative Cooling Work?
When the heat is on, portable evaporative cooling offers a breezy oasis – just be sure to watch your humidity.
For more tips on keeping your cool when temps rise, read my other articles on beating the heat.
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