Buying an evaporative cooler is one way to beat the heat, especially if you live in a less humid climate (we're looking at you, Arizona!). There are plenty of swamp cooler options out there, and some make some impressive claims.
With some attractively priced models out there, we wondered how well the claims matched reality. So we've brought in a couple of models to take a closer look and see what you're getting for your hard-earned money.
What is the difference between an evaporative cooler and a swamp cooler? In short, nothing. They are just two different names for the same device.
How do evaporative coolers work?
An evaporative or swamp cooler works by taking in dry air, adding moisture to it, and then blowing out more humid air than it started with.
The fan blades are responsible for the airflow, just like a normal fan. It draws air in through the rear and sides, and expels it through the front at acceleration.
There is a water reservoir at the bottom of the swamp cooler. A pump pulls it over the top and distributes it over a filter-like pad that covers the back and sides. It is able to absorb additional moisture as the fan pulls air through them. Instead of coming in the form of fog, it raises humidity levels.
It might sound like you're just taking in the Arizona heat and adding Florida humidity, but it's actually a lot more comfortable than that. The fan moves air over you, and the extra moisture promotes evaporative cooling of your skin, which is more effective than airflow alone.
It is worth noting that evaporative coolers perform best when the relative humidity is below 60%.
Buying a Swamp Cooler
We've brought together four different evaporative coolers to compare what they claim with what they offer. In the meantime, we'll help you understand what we're looking for in a swamp cooler so you can decide for yourself which model is best for you.
NOTE: When you first turn on your evaporative cooler, you may smell ammonia. This is because the way they treat the filter is normal. Go ahead and set it outside and rinse it with a can of water overnight. The smell will go away on its own – usually after a few hours.
Swamp Coolers: What We Look For
- CFM (cubic feet per minute) : This is a measure of airflow. The higher the value, the more air passes through you and the better the cooling. Some of the numbers we measured differed significantly from the manufacturer's claims.
- Airspeed : We check the airspeed every once in a while to see how the cooling effect transfers when you get out of the cooler. Models that reach farther are better at cooling large spaces efficiently.
- Noise level : You need to be relatively close to the swamp cooler. The less noise it makes, the less you need to compete with it to hear and be heard.
- Current draw : Evaporative coolers don't use a lot of power, but if you're running on solar or a generator, the more energy efficient the better.
- GFCI (Ground Fault Circuit Interrupter) : These devices protect you from electrical shock caused by faults. According to UL 507, products sold and intended for outdoor use must have a GFCI plug that complies with this standard.
- Tank Dimensions : Even though excess water is being circulated back into the tank, some water is constantly being sucked into the air. The larger the tank, the less often you need to refill it.
- Filter Size : Larger filter pad surface area means more air to water contact and better humidity conversion.
- Fan blade material: Metal and plastic blades can produce similar airflow, but plastic blades can deform over time when placed in harsher outdoor environments. Any changes to the blades could end up affecting airflow and fan noise.
- Price : Hey, everyone has to stay on a budget these days, right? Cheaper isn't always better, though. Consider the quality and performance of the product versus the price to gauge the value of a cooler.
Evaporative Cooler Test Results
According to the manufacturer, we bring evaporative coolers ranging from 1300 to 3100 CFM and occupying an area of 500 to 950 square feet. However, we discovered that not all swamp coolers are created equal.
Hessaire MC37M Swamp Cooler
circulation flow meter
The Hessaire MC37M claims to get 3100 CFM, which is by far the largest in our sample group. We measured a discharge area of 220.24 square inches (1.53 square feet). With an average airspeed of 1352 feet per minute (15.36 MPH), we calculated an actual airflow of 2067 CFM. This is a solid value, but a difference of more than 1000 CFM or 34% from the claimed mark is worrisome.
airspeed change
Standing on the exit, the Hessaire MC37M averaged 1352 fpm. Here's how it varies with distance:
- 0 feet: 1352 ft/min (15.63 mph)
- 3 feet: 1100 ft/min (12.5 mph)
- 6 feet: 942 ft/min (10.7 mph)
- 12 feet: 625 ft/min (7.1 mph)
Maintaining this air velocity can keep a considerable area cool. In fact, it has the longest effective range of any unit we've tested.
Noise level at 3 feet (A-weighted, slow response)
- Low: 74 dB
- Medium: 83dB
- High: 87 dB
Not surprisingly, the most powerful swamp coolers we've tested are also the loudest. If you're sitting close to it, you might have a hard time hearing conversations. However, this model has a solid range and you can go farther and still feel the airflow.
current consumption
We attach the clamp meter to a special extension lead for measuring current draw. We measured the following results:
- Low: 0.9 Amps
- Medium: 1.2 Amps
- High: 1.7 Amps
The Hessaire MC37M requires more current draw than other models we tested. If you are using a generator or solar, you may want to look at other options to increase energy efficiency.
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Hessaire doesn't provide a GFCI plug on the unit, but they also don't specifically state that the unit is suitable for outdoor use — at least not in their owner's manual or website. If you are using this unit outdoors, we strongly recommend that you use a GFCI extension cord or plug it into a GFCI outlet to reduce the risk of electric shock, even though they actually advise the opposite in their manual.
tank size
The Hessaire's 10.3 gallon fuel tank is smaller in size than other tanks in its class, which means you'll need to top up more often.
filter size
With 818 square inches of filter space, this Hessaire swamp cooler covers a reasonable area, but some competitors have a higher ratio of filter area to airflow.
supplementary notes
- 3 plastic blades for the fan
- Tanks are bottom filled or connected via a garden hose
- Seams along the plastic are sharper and rougher than other models
- This unit has a set of quality casters that roll and turn easier than others we've tested
- Does not have vertically adjustable blinds, but includes automatic lateral swing
more numbers to know
- Model: Hessel MC37M
- Manufacturer's recommended coverage area: 950 square feet
- Weight: 40 lbs
- Dimensions (H/W/D): 37.25 x 24.13 x 16.25 inches
- Price: $299
Honeywell CO610PM Evaporative Cooler
circulation flow meter
Honeywell CO610PM has 2100 CFM. We measured a discharge area of 233.59 square inches (1.62 square feet). It has an average airspeed of 1294 feet per minute (14.70 mph) and we calculated an actual airflow of 2099 CFM. It's an excellent airflow that's easily close to its claimed value.
airspeed change
Looking at emissions, the Honeywell averaged 1294 fpm. Here's how it varies with distance:
- 0 feet: 1294 ft/min (14.70 mph)
- 3 feet: 1082 ft/min (12.3 mph)
- 6 feet: 862 ft/min (9.8 mph)
- 12 feet: 563 ft/min (6.4 mph)
In terms of coverage area, this is another winner for larger spaces. Its effective distance is very close to Hessaire MC37M.
Noise level at 3 feet (A-weighted, slow response)
- Low: 80 dB
- Medium: 83dB
- High: 85dB
The Honeywell's highs are quieter than the Hessaire's, and the lows are louder, matching its mid-range noise.
current consumption
- Low: 0.9 Amps
- Medium: 1.0 Amp
- High: 1.1 Amps
If you're looking for the perfect balance of airflow and energy efficiency, the Honeywell CO610PM has you covered. It uses 35% less power at high power than the Hessaire unit and has slightly more airflow as tested.
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Honeywell includes a GFCI plug on this unit. In our test group, it was the only model with one. It's also the only model that actually recommends and specifies outdoor use in its materials and product descriptions.
tank size
Honeywell's 14 gallon tank has a large capacity and gives you more time between refills than similarly sized units.
filter size
This large Honeywell evaporative cooler has 929 square inches of filter space—nearly 15 percent more than the Hessaire. This should result in better humidity conversion and more efficient evaporative cooling.
supplementary notes
- 5 metal blades for the fan
- Tank is top filled or connected with a garden hose
- The top container can hold a handful of ice cubes to keep the water temperature down as you fill, a useful addition that others don't have
- Smaller casters don't roll well on concrete joints and tank-filled decks
- Includes manual vertical blind adjustment and automatic lateral swing
more numbers to know
- Model: Honeywell CO610PM
- Manufacturer's recommended coverage area: 850 square feet
- Weight: 45 lbs
- Dimensions (H/W/D): 40.50 x 27.75 x 18.00 inches
- Price: $499
Luma EC220W Evaporative Cooler
circulation flow meter
The Luma Comfort EC220W claims an airflow of 1650 CFM. We measured a discharge area of 230.21 square inches (1.60 square feet). At an average of 1197 feet per minute (13.60 MPH), we calculated an actual airflow of 1914 CFM. It's unusual for a manufacturer to claim a lower CFM than what we tested, but it was a nice surprise. Maybe Luma is just conservative.
airspeed change
The Luma EC220W was on top of the discharge, delivering an average of 1197 fpm. Here's how it varies with distance:
- 0 feet: 1197 ft/min (13.60 mph)
- 3 feet: 844 ft/min (9.6 mph)
- 6 feet: 607 ft/min (6.9 mph)
- 12 feet: 387 ft/min (4.4 mph)
12 feet is right on the edge of the Luma's reasonable cooling range. It's a few feet smaller than the previous two models, but still covers a decent area.
Noise level at 3 feet (A-weighted, slow response)
- Low: 78 dB
- Medium: 80dB
- High: 81 dB
The Luma's noise level drops with its slightly lower airflow. If you're annoyed by the noise levels of other devices, this one strikes a good balance between loudness and airflow.
current consumption
- Low: 1.0 Amps
- Medium: 1.1 Amp
- High: 1.3 Amps
While not as energy-efficient as the Honeywell model we tested, the Luma EC220W requires less energy than the larger Hessaire unit to run at medium to high power.
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Luma does not include a GFCI plug on this unit, although it appears to be intended for indoor/outdoor use. We recommend that you use a GFCI extension cord or plug it into a GFCI outlet to reduce the risk of electric shock when used outdoors.
tank size
The Luma's 10.6 gallon tank size is ample for the size of the unit and the area it is designed to cool.
filter size
This Luma evaporative cooler has 688 square inches of filter space. This is an effective filter area to airflow ratio that is closer to that used by Hessaire's larger units.
supplementary notes
- 5 metal blades for the fan
- Fill the tank at the bottom or with a garden hose (requires cutting off the end of the hose to use the included hose clamp – a bit of a hassle)
- Casters are on the small side, but roll and turn well
- Includes manual vertical blind adjustment and automatic lateral swing
more numbers to know
- Model: Luma CO610PM
- Manufacturer's recommended coverage area: 650 square feet
- Weight: 42 lbs
- Dimensions (H/W/D): 41.13 x 27.00 x 17.00 inches
- Price: $369
Hessaire MC18M Swamp Cooler
circulation flow meter
The Hessaire MC18M represents the compact side of evaporative coolers, claiming 1300 CFM. We measured a discharge area of 115.41 square inches (0.80 square feet). With an average airspeed of 1009 feet per minute (11.47 MPH), we calculated an actual airflow of 808 CFM. Like its big brother, it's also significantly less than its claimed value – in this case close to 500 CFM or 38%.
airspeed change
Standing on the exit, the Hessaire MC18M pushed an average of 1009 fpm. Here's how it varies with distance:
- 0 feet: 1009 ft/min (11.47 mph)
- 3 feet: 783 ft/min (8.9 mph)
- 6 feet: 493 ft/min (5.6 mph)
- 12 feet: 308 ft/min (3.5 mph)
Being a compact unit, it's no surprise that the range is more limited than larger units. This Hessaire Swamp Cooler performs best within 10 feet.
Noise level at 3 feet (A-weighted, slow response)
- Low: 67 dB
- High: 77 dB
This model lets you deal with less background noise when having a conversation is a top priority.
current consumption
- Low: 0.3 Amps
- High: 0.4 Amps
If you have choice or an occasional energy conscience, this Hessaire unit consumes significantly less energy than any larger model. Requiring a high current of only 0.4 amps, it is possible for even a portable solar unit to keep up with the power needed to run it.
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Same as the model above. Hessaire does not provide a GFCI plug on this unit, but they do not advertise it as an outdoor product either. We recommend that you plug it into a GFCI outlet to reduce the risk of electric shock when used outdoors.
tank size
Despite the much smaller footprint, the Hessaire's 4.8-gallon tank doesn't seem small for the unit.
filter size
With 278 square inches of filter space in the rear of the unit (no side filters), less airflow filters than other units. It won't be as effective at humidity conversion as those with better ratios.
supplementary notes
- 3 plastic blades for the fan
- Tanks are bottom filled or connected via a garden hose
- Fill door opens wide enough to drop ice cubes into tank by hand
- Seams along the plastic are sharper and rougher than other models
- Rolls and turns good casters for a unit this size
- Includes manual vertical blind adjustment, but no lateral adjustment
more numbers to know
- Model: Hessel MC18M
- Manufacturer's recommended coverage area: 500 square feet
- Weight: 16 lbs
- Dimensions (H/W/D): 28.75 x 19.75 x 10.75 inches
- Price: $209
Check out our other buying guides and in-person reviews here!