Evaporative Coolers vs Air Conditioners: Which Type to Choose & Why

First off, we’ll look at the differences between evaporative air coolers and air conditioners. Check out which of these HVAC devices is better for your home, including a comparison of pros and cons.

Both types are technically “air coolers” because they condition the air by cooling it, but there the similarity ends. The main differences are in how they work, perform, efficiency, and comfort level they deliver, so let’s compare them.

The difference between evaporative coolers and air conditioners

According to Wikipedia: "Evaporative coolers lower the temperature of air using the principle of evaporative cooling, unlike typical air conditioning systems which use vapor-compression refrigeration or absorption refrigeration."

In other words, air conditioners draw moisture out of the surrounding air, while evaporative coolers add, increasing the air humidity.

Evaporative coolers – Types and benefits

Evaporative coolers may be older technology, but they are among the most efficient cooling options available today. They lower home temperatures by evaporating water from the air flowing through them with a powerful fan system; the result is a cool fresh breeze.

An evaporative cooler has a similar refreshing effect on your body as you would get if you put a wet piece of cloth on your body while it is hot outside. Or, in the same way as your body would cool itself with sweat. The process is very simple – your body temperature decreases as water evaporates.

Evaporative devices can also help to reduce some of the symptoms related to dry skin, itchy eyes, and irritated throat.

They can be large whole-house systems using window or roof-mounted units with ducting to move the cold air throughout the house, also small mobile units, which can be moved from room to room in smaller properties.

Evaporative coolers can be equally used indoors and outdoors. You just have to plug them in and add water.

The device is made of several components such as a fan, an air filter, a water tank, a thick pad, and some controllers for the automation.

There are three main types of evaporative coolers

Direct Evaporative Coolers which pull in surrounding air, pass it through wet pads, cooling it, then push it back into the room with higher water content. By increasing the humidity this way, it cools, moistens, and freshens the air in the process, which helps to remove still air from the area.

Standalone Systems are designed to cool whole homes and can be roof-mounted and linked to ductwork fitted throughout the house. The system requires a larger diameter/size ductwork due to the higher volume of air they handle.

Portable Evaporative Coolers are best suited for small areas or individual rooms. They can cost from a few hundred dollars to more than $1000. What makes them popular, except the affordability, are features such as wheels for easy mobility, plug-and-play, and ventless operation.

Evaporative cooling units are simple and work by pulling air through the unit and passing it through wet pads, and as the water evaporates, it cools it, sending fresher cooler air into the room.

If looking for more advanced and efficient coolers, check out two-stage models, which are recommended for regions with frequent high daily temperatures.

This type of coolers is ideal for areas that have a hot, dry climate with low humidity. By using water to cool the air, it’s adding moisture, so if the humidity level is already high, an evaporative cooler will make it even higher, which is why these units are also referred to as swamp coolers. The EPA (Environmental Protection Agency) recommends between 30 and 60 percent relative humidity to deter mold, mildew, and fungus.

Pros

• Cheaper to buy. 
• Easy to install.
• Cheap to run.
• Excellent in hot, low humidity areas.
• Eco-friendly, no chemicals, and low carbon footprint.
• Runs quietly, no compressor.
• It can run efficiently even with the doors and windows open.
• It can lower the temperature up to 12 degrees.
• More efficient than the AC.
• With the right quality filters, it improves air quality.
• It delivers a steady stream of fresh air into the room.

Cons

• Requires between 3.5 and 10.5 gallons per hour to run efficiently (NAHB).
• Adds to humidity, which could cause mold in already high humidity areas.
• It needs a fresh air supply with open windows or doors to be effective.
• Not suitable for high humidity climates.
• Requires a higher level of maintenance.
• Does not lower temperature as much as AC.

The average cost to install an evaporative system for a 1500 sq. ft. home is around $3,900.*

*(This is an average guide cost, which will vary according to your location and the complexity of your installation. Contact your local HVAC specialist for an accurate estimate).

Tips: To maximize the efficiency of evaporative coolers, ensure that there is a steady delivery of fresh air near the air intake fan. Water quality inside the tank should also be fresh and free of contaminants, with no mold and mildew in the reservoir.

Size the unit to the square footage of your room – under-sizing or oversizing is not recommended.

Before you buy one, check first the unit’s air delivery rate in cubic feet per minute (cfm) and how much air changes per minute it provides. Use this link to find more info about average temperatures and humidity in your area.

Air conditioners

In North America, we have every type of climate condition known to man, from the freezing Arctic in the far north to humid tropical environments in the south with everything imaginable in-between. So, while evaporative cooling is excellent in the dry and hot regions, not everyone lives there, which is why air conditioning has its place.

How do air conditioners work?

Air conditioners pull moisture-laden air in and pass it over coils, then re-circulate it and push it back into the area with dry, cool air. The AC works the best in the closed area with continuous air circulation.

The process uses refrigerants, the same as in a refrigerator, and is more expensive in energy to run. The upside is that they’ll operate efficiently in almost every variation of climate there is in North America.

Air conditioning has many benefits. It is suitable for all sizes of home and commercial spaces, from single mini-split systems covering a small area to installations in large homes or commercial spaces. They also act as a dehumidifier, which reduces mold, mildew and fungus, and other nasties from your environment. 

The cost of air conditioning is higher than an evaporative system because it involves more components like coils and compressors, plus the installation costs will be higher, depending on which system you choose. There is also a greater need for maintenance required, and if air conditioning systems aren’t maintained, the costs to repair them can be high.

Pros

• Precise temperature control.
• Energy-efficient; power used versus output.
• Use in almost every climate. 
• Scalable, from a small house to large commercial premises.
• Cools and heats, when equipped with the heat pump.

Cons

• Higher cost to buy.
• Higher cost to install.
• Higher cost to run.
• Maintenance needs regular maintenance and cleaning.
• Uses environmentally unfriendly refrigerants.
• They emit higher levels of CO2. 
• Noisier
• It recirculates the same air throughout the house.

The average cost to install an air conditioning system for a 1500 sq. ft. home is around $5000.*

*(This is an average guide cost, which will vary according to your location and the complexity of your installation. Contact your local HVAC specialist for an accurate estimate).

Air quality

Another consideration when choosing between air coolers and ACs, is which system delivers better air quality? We use these systems to keep us cool and breathe the air they produce in our homes. On a straight comparison, evaporative cooling delivers a higher air quality. They don’t dry out the air, and you can keep windows and doors open even when the system is running, so you are not living in a sealed box.

The air is fresher and healthier, which could be even more critical if you suffer allergies. An evaporative cooling process can help reduce allergy symptoms and improve breathing for those who have asthma.

What about the environment?

As you probably know, the EPA has phased out older refrigerants that have been so devastating to the environment and replaced them with more eco-friendly versions, which are still not free of risks.

Running an air conditioner emits CO2, mainly because the energy used to run them uses electricity, which in turn uses coal, oil, and natural gas, all of which emit CO2 to produce power.

Evaporative coolers use less energy, which lowers running costs and is kinder to your skin and body in general, including the environment.

Conclusion

If you live somewhere hot and dry, you should consider an evaporative cooling system for your home. They work efficiently and are lower in cost to buy, install, and run.

The slight downside is it will never cool a home as efficiently or to as low a temperature as an air conditioning system will. But as you’ve seen, there are several major benefits with the evaporative cooler, and only you can decide which suits your budget, requirements, and preferences overall.

Air conditioning systems are popular for those of us unfortunate enough not to live in a hot, dry climate, so perhaps they will be your cooling choice at the end of the day. Now you have some facts to help you make the right choice, and always remember, your local HVAC professional has the answers.