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Robbins Heating & Air Conditioning, Inc. Blog

What time of day do I run my swamp cooler?

It’s the peak of summer and you’re wondering if you should crank up your swamp cooler to try and beat the heat.

robbins fixing a swamp cooler in farmington nm

How A Swamp Cooler Works

Because of our dry climate, swamp coolers can be effective cooling systems. They take in dry air, moisten it by running it through soaked pads, and pump that newly cooled air into your home. This not only adds moisture to your home but simultaneously cools it down.

So they are a cheaper option than refrigerated air and work well in dry climates, and evaporative coolers cool the air they bring into the home by 10-20°. So the air being circulated through your home is 10-20° less than the temperature outside. If there is more humidity in the air, that equals less cooling potential because the air is already moist.

Insulation also plays a part in cooling your home. Good, quality insulation will help hold that cool air in, bringing your home’s temperature down. If air is able to escape, then the overall temperature may not be as low due to that cooler air being able to get out.

And something to note, swamp coolers only cool the air they bring in, not necessarily the whole home. So it may seem like you’re running your evaporative cooler more. So should you run your cooler all day then, to help keep out the heat?

Run your evaporative cooler from early morning till afternoon, then give it a rest.

Here’s why.

Early morning to Midday

Early morning air is already naturally cooler. Your evaporative cooler can take in that already cool air, make it colder, and circulate that air throughout your house. This drops temperatures and ensures that your house is at its peak coolness to start off the day. Sounds pretty good!

By mid-morning, swamp coolers can still produce great quality, cool air to get you through your morning routine. The air is still cool enough that the evaporative cooler can still function well and give you the comfortable temperatures you need.

Now, some assume that midday is the hottest portion of the day. It’s actually not! At noon, temps are still rising, but it’s still a good time for you to run your swamp cooler, though you will notice a difference between those early morning hours and lunch time temperatures in your home.


Afternoon, between 2:00 – 4:00 pm, typically hosts the hottest part of the day. And – if you can help it – try not to run your evaporative cooler as much. While this may sound odd, it may actually help keep your home cooler. Here’s where installing a digital cooler is beneficial.

With this digital cooler you can set the temp, let the swamp cooler bring your home’s temperature down, and then close up your home. Closing everything up holds in all the cool air and lets you see how long your house can hold on to that coolness. This approach can you help you beat the hottest part of the day.

Evening and Night

Evening and night are key times to capitalize on your swamp cooler. As you wrap up the day, let in that cool, fresh evening air as the sun finally goes down and those temperatures start to decline.

Running your evaporative cooler during the night will not only give you cooler air to circulate (bringing the overall house temperature down) but it will contain less pollen – a nice additive for those who struggle with seasonal allergies.

One Last Thing

But what about those few days during the summer where your evaporative cooler just can’t seem to keep up? The problem isn’t our intense desert heat, the problem is the humidity.

Humid air is a swamp cooler’s biggest enemy. When temperatures rise, humidity, or water vapor in the air, typically drops. Then your evaporative cooler can do its job of moistening and cooling the air. But when the air becomes humid, there’s already so much water in the air that your swamp cooler can’t perform its job as well.

So on those few summer days where it might feel like your evaporative cooler isn’t keeping up, know it’s still working hard to fight against that humid air. It’s still doing its job as well as it can, and once that humidity drops back down (which, thankfully, is regular for our region!) your house will go back to feeling cool and comfortable.

And a quick pro tip? If you just can’t beat the heat – try ice. Grab a block of ice and put it in the cooler pan. This will definitely drop the water temperature and generate some really cool air to circulate your home!

Call Robbins today, and let us take care of everything!

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