Comparison of Evaporative cooling to phase-change air conditioning:

Advantages

Less expensive to install

• Estimated cost for installation is about half that of central refrigerated air conditioning.[8]

Less expensive to operate

• Estimated cost of operation is 1/4 that of refrigerated air.
• Power consumption is limited to the fan and water pump vs. compressors, pumps, and blowers.

Ease of Maintenance

• The only two mechanical parts in most basic evaporative coolers are the fan motor and the water pump, both of which can be repaired for very little and often by a mechanically able homeowner.

Ventilation air

• The constant and high volumetric flow rate of air through the building reduces the age-of-air in the building dramatically.
• Evaporative cooling increases humidity, which, in dry climates, may improve the breathability of the air.
• The pad itself acts as a rather effective air filter when properly maintained; it is capable of removing a variety of contaminants in air, including urban ozone caused by pollution, regardless of very dry weather. Refrigeration-based cooling systems lose this ability whenever there is not enough humidity in the air to keep the evaporator wet while providing a constant trickle of condensate that washes out dissolved impurities removed from the air.

Disadvantages

Performance

• High dewpoint (humidity) conditions decrease the cooling capability of the evaporative cooler.
• No dehumidification. Traditional air conditioners remove moisture from the air, except in very dry locations where recirculation can lead to a buildup of humidity. Evaporative cooling adds moisture, and in dry climates, dryness may improve thermal comfort at higher temperatures.

Comfort

• The air supplied by the evaporative cooler is typically 80–90% relative humidity; very humid air reduces the evaporation rate of moisture from the skin, nose, lungs, and eyes.
• High humidity in air accelerates corrosion, particularly in the presence of dust. This can considerably shorten the life of electronic and other equipment.
• High humidity in air may cause condensation. This can be a problem for some situations (e.g., electrical equipment, computers, paper/books, old wood).

Water

• Evaporative coolers require a constant supply of water to wet the pads.
• Water high in mineral content will leave mineral deposits on the pads and interior of the cooler. Bleed-off and refill (purge pump) systems may reduce this problem.
• The water supply line may need protection against freeze bursting during off-season, winter temperatures. The cooler itself needs to be drained too, as well as cleaned periodically and the pads replaced.

Miscellaneous

• Odors and other outdoor contaminants may be blown into the building unless sufficient filtering is in place.
• Asthma patients may need to avoid poorly maintained evaporatively cooled environments.
• A sacrificial anode may be required to prevent excessive evaporative cooler corrosion.