What Is Evaporative Cooling? Here’s What to Know
This lesser-known alternative of central AC can be just as effective
Highlights
Evaporative cooling uses evaporation to lower room temperatures.
Evaporative coolers are available as direct, indirect, or mounted units.
They are best for homes in low-humidity climates, like Arizona and New Mexico.
Evaporative coolers cost $1,560 to $3,740 to install.
If you’re looking for a new way to cool your home or workspace when outdoor temperatures rise, consider evaporative cooling, especially if you live in a warmer climate with high humidity. Central air conditioning may be the more widely used form of air conditioning, but evaporative cooling can be just as effective—and less expensive—than the traditional form. Consult an AC installer to determine if this option works for your home, and follow our guide to learn more about this alternative cooling system.
What Is Evaporative Cooling?
| Pros of Evaporative Cooling | Cons of Evaporative Cooling |
|---|---|
| Consumes less energy | Monthly maintenance required |
| Uses fresh air supply | Doesn’t get as cool as central AC |
| Less expensive to maintain | Uses a lot of water |
| Good for climates with dry air | Has installation limitations |
| Adds moisture to air | Requires access to quality air |
Evaporative cooling uses water evaporation to cool the air. Evaporative coolers, also known as swamp coolers, contain pads saturated with water. As the unit pulls in hot air from the room, the heat evaporates water on the pads. The cooler air is then pushed back out into the room. In addition to the water-soaked pad, the cooler also has a water tank, water pump, and fan motor.
A standard evaporative cooler can lower air temperatures by 15 to 40 degrees Fahrenheit. Additionally, smaller window units can lower temperatures from 5 to 15 degrees Fahrenheit. Consult a local AC installer about whether this cooling method is the right fit for your home.
Pros of Evaporative Cooling
Consider these benefits of installing an evaporative cooling system.
Consumes Less Energy
Because evaporative cooling relies on the natural process of evaporation, these units use less energy than traditional central air conditioning units. In most cases, evaporative cooling requires only a pump and a fan to circulate cool air through your space, making it better for your pocketbook and the environment. An evaporative cooler uses between 200 and 400 watts of power to run, whereas central AC uses 3,000 to 3,500 watts per hour.
Uses Fresh Air Supply
Evaporative cooling units use a combination of air and water to lower the home’s indoor temperature. This method helps lower carbon emissions and can also improve ventilation while reducing indoor pollutants. This process is much more environmentally friendly than central AC, which uses refrigerants that can emit harmful chemicals.
Less Expensive to Install and Maintain
From the initial purchase to installation and maintenance, one of the biggest pros of evaporative cooling units is that they’re less expensive than central air conditioning units. Evaporative coolers cost $1,600 to $3,740 to install. On the other hand, central air conditioning units cost $3,900 to $7,940 to install.
Although you may have to check your evaporative cooler on a regular basis, it’s not as pricey to replace components since you can often DIY repairs. The simplicity of the system’s design means the elements inside cost less to replace and are easier to manage than a more complicated system like central AC.
Add Moisture to Air
Regions known for their hot, dry conditions can benefit from evaporative cooling since it adds humidity back into the air. This process can help moisturize your skin and prevent conditions that result from a lack of moisture, such as congestion and bloody noses. When evaporative cooling units run, the air they draw in comes in contact with water, causing it to evaporate. This method allows the unit to pump those molecules into the air that in turn cools down the room.
Cons of Evaporative Cooling
Consider these drawbacks of installing an evaporative cooling system.
Monthly Maintenance Required
For your unit to last and run efficiently, you’ll need to inspect it monthly. Get in the habit of unplugging your unit once per month to check out the inside of the system and look for damaged or worn-out parts. You should also inspect whether the water reservoir is full.
These regular check-ins will prevent scale buildup on the wet pads. You’ll need to clean the pads once or twice per year, and plan to replace them every two to three years. Although the units are less expensive to maintain, you will have to service it more often to keep it in tip-top shape.
Doesn’t Cool as Well as Central AC
The hotter the temperatures and the warmer the air, the harder it will be for your evaporative cooling unit to cool down. Central air conditioning units are easier to control and adjust since they rely on refrigerant or other cooling methods to push icy-cold air out. If you live in an area that experiences extremely high temperatures for extended periods, an evaporative cooling unit may not be the best fit, especially if you’re trying to cool a large area. This type of air conditioner is best for regions with moderate to hot conditions.
Unit Uses a Lot of Water
You’ll need a constant water supply to keep your evaporative cooling unit running, so if you live somewhere without quality water or if water is scarce, you may need to consider a different option. Without water, the unit won’t be able to cool down the air that’s pushed back into the room.
Installation Limitations
Some evaporative cooling units have installation limitations. For example, you’ll need to install a ducted or centralized system on the roof, so you’ll need enough space to put one in place. Other types will need to be in an area with proper ventilation and access to fresh air supply. If you’re unable to provide a place for these units, an evaporative cooling unit may not be the best fit for you.
Requires Access to Quality Air
If the air where you live contains pollutants and allergens, it may not be ideal to push that air inside your space. You’ll need access to quality air to cool your home with an evaporative cooling unit. This is especially true if you are prone to allergies or have respiratory issues. People who live in states prone to wildfires may want to steer clear of evaporative cooling units.
Types of Evaporative Coolers
Once you decide to jump on the evaporative cooling bandwagon, it’s time to decide which type of unit is best for your specific needs.
Direct
Also called swamp coolers, direct evaporative coolers require no installation, are portable, and are the easiest to maintain out of all variations. These appliances use natural cooling properties from water vapor to turn warm air into cooler air molecules pushed out of the unit and into your space by a powerful fan.
Indirect
Indirect evaporative coolers are not portable and don’t add humidity to the air, so they’re ideal for spaces such as restaurants or businesses. Since these coolers are much bigger than direct options, they’re often more expensive and need professional installation to cool the space properly. These evaporative coolers typically require ductwork and work extremely well in regions with high temperatures since the hotter air combined with a secondary air source is chilled by evaporation.
Mounted
As its name suggests, mounted evaporative coolers are a subtype of indirect coolers that mount to either the ground, a window, or your home’s roof. Ground mounting is the least used option of the three since it doesn’t cool air as well as window or roof-mounted coolers. Most private homes will mount their coolers on a window, while industrial spaces or businesses tend to use roof-mounted coolers.
Requirements for Evaporative Coolers
Before you install an evaporative cooler, here are some requirements you should keep in mind.
Climate
Evaporative coolers work best in dry, hot climates with low humidity. They’re a good fit for places like New Mexico or Arizona. If you live in an area with high humidity, it may be best to install an air conditioning system instead. Although the cost of an AC unit installation is higher, it’ll work better in the long run.
Airflow
Evaporative coolers need proper airflow and ventilation. While some whole-house units have the necessary ventilation through the ductwork, portable coolers require you to keep your windows cracked. Proper airflow allows the hot air and moisture to escape. Make sure to secure your windows with a locking mechanism if you believe the partially open windows could be a security issue.
Maintenance
During the hot months, you must conduct simple but regular maintenance to keep your evaporative cooler in tip-top shape. Every month, check your pads, filters, water reservoir, and water pump. Clean off any sediment or mineral buildup.
You can clean buildup with a stiff brush or kitchen sponge. You can soak any parts with heavy buildup in a 50/50 water-white vinegar for 2 hours. You can also soak your cooling pads in a 50/50 water-vinegar mixture for a minute to clean them off.
In addition, you need to schedule annual maintenance calls. Hire an HVAC company near you to take a look at your unit after the hot season. The tech will clean your cooler and check and repair or replace any necessary parts.