Why does my swamp cooler smell like fish?


As you know, your swamp cooler works by using water to moisten your swamp cooler pads, so that as the air moves through the wet pad, it cools down the air while also adding some humidity to your home’s dry air. Because the pads use water, this can sometimes cause them to smell over time, like a kitchen sponge. You’ve probably been running your cooler non-stop throughout the summer, so you constantly have water running through the cooler. Bacteria is usually the culprit of the bad fishy smell and the last thing you want to do is introduce that into your family’s home. The only way to completely eliminate the fishy smell is to replace your pads. But, we do have a couple of tips that may help reduce the smell listed below.

Replacing Your Swamp Cooler Pads

We always recommend changing the pads on your swamp cooler once a year (with the exception of Mastercool swamp cooler pads) prior to the start of each summer. As we mentioned above now that we are in the middle of summer you’re likely running your cooler every day. The only way to eliminate the odors completely would be to replace the pads again to take care of those unwanted smells from tainting your home’s air. You have a couple of options that range from good, better, and best. You can visit our blog that will go into depth about which swamp cooler pad is right for you. If you don’t feel comfortable changing your pads yourself or cannot access your cooler if it is on the roof please call TLC or another professional to replace your pads.

Swamp Cooler Pad With Mold And Debris
This pad has debris holding water in and is starting to get mold in some areas.

Ways to Help Deodorize Your Swamp Cooler

Perhaps you have already replaced your swamp cooler pads this year, but are still experiencing some level of odor. Or you might feel that since summer will be winding down soon you might not want to replace your pads twice this year. There are a few things you can do to deodorize your evaporative cooler that may help reduce odors.

  1. Purchase a swamp cooler deodorizer – You can purchase a swamp cooler deodorizer to place in your swamp cooler from most home improvement stores. These are specifically made for coolers. If you need help accessing your cooler to install this deodorizer please call us or another HVAC professional. These deodorizes can’t eliminate the fishy smell completely but can reduce the odor if it is not that bad.
  2. Let your pads dry – If the temperatures are easing a bit you may want to run your cooler with the fan only to allow the pads to dry. If it is comfortable enough to be able to run the fan only for a few days, this can allow the pads to dry and can help reduce odors. We know this depends on the temperature outside and your comfort range. Again, the only way to completely eliminate the odor is to replace the pads.

Keeping the Smell Away Next Year

There are a few steps you can take to make sure the odor is less likely to return next year. 

  1. Make sure that you drain the reservoir thoroughly at the end of each summer. 
  2. Use a stiff wire brush to clean dirt, dust, and mineral deposits in the tank.
  3. Keep the unit covered during the winter to protect it from dust and dirt (You can get them at your local hardware store or purchase them online if you do not have one).
  4. Or avoid the hassle and have a professional HVAC expert winterize and start up your cooler each year to ensure proper maintenance.