If you have a cooling tower on your premises, you likely have a rather large area to heat and cool on a daily basis, or have very specialised temperature requirements. Cooling towers are often used in industrial HVAC installations, and they can provide some of the more efficient heating and cooling solutions for these spaces. But they do have one major drawback – they get dirty. Specifically they get slimy, accumulating a lot of dirt and moisture that can build up fairly quickly at times. So if you have a cooling tower, one of your regular maintenance tasks should be to keep it clean. And while it’s a slightly gross, difficult and sometimes time-consuming job, the long term benefits to your bank account are worth it.

What Causes Slime Build Up?

The slime build up in your cooling tower might seem a bit disgusting, but it’s actually a perfectly normal by-product of this type of system. It’s a substance called biofilm, which is a product of the microorganisms that live in your boiler and heating system. Scientists like to call this gooey coating ‘Extracellular Polymeric Substances’ – but if you’ve ever had first-hand experience of it you might just call it slime!

The microorganisms that have made their home in your property’s boiler or cooling tower create this biofilm as a way or protecting themselves. They live within or underneath this protective sheath, breeding and thriving – so the more slime you have, the more microorganisms have been living in your cooling tower rent free.

But you do need to be careful when you go in to clean this slime away, as some of the microorganisms within it can be quite dangerous. For example, certain bacteria that reduce sulphites can cause some significant metal corrosion in your systems. Legionella is another common bacterium found in the average cooling tower, and the biofilm this produces is the leading cause of Legionnaires disease – a very dangerous form of pneumonia that can be deadly. This is one of the reasons we recommend you hire a professional HVAC maintenance company (like us) to tackle cooling tower cleaning, as we have the experience, knowledge and specialist equipment to do this job quickly and safely – and dispose of the slime in a safe way afterwards.

That Slime Is Costing You Money

Having that biofilm living in your cooling tower isn’t a great thing. Not only is it a health risk, but it can also cost you money over time. Not a lot at first granted, but the longer you leave it the more build-up you get, and the more money you end up throwing away. For example:

  • Your cooling tower will not be operating as efficiently. Biofilm is an incredibly good insulator, and if it gets into your cooling towers it will affect the way their ability to work properly. This means you will be using more power and more money to keep the towers working properly. To put it into perspective – a layer of biofilm just 1/5 of a millimetre thick will reduce your HVAC efficiency by over 10%!
  • You are putting yourself and your employees and even the public at risk. If you have an outbreak of biofilm in your system, it‘s the first sign that worse is to come. You could, for example, be harbouring a strain of waterborne pathogen, holing any number of bacteria and viruses including Legionnaires’ disease. If your premises is close enough to be spraying mist over a local populated area, you are liable for any damages and illnesses stemming from that mist.
  • Finally – you are risking a lot of damage to your equipment, which could cost you a small fortune in repairs or replacements. That sulphite reducing or iron depositing bacteria that cause biofilm to form can also destroy steel – the very substance your cooling towers are made of! In severe cases, these bacteria can eat away at 1-inch-thick steel tubing in as little as 18 months. Can you justify replacing your entire cooling system every 2 years just because of some slime?


So ask yourself this – if you have a cooling tower on your premises, when was the last time it was cleaned? If you don’t know, or it was quite a while ago, now is the time to take action. At Bonus Eventus Maintenance cleaning cooling towers is a part of our regular maintenance work on your HVAC system, so having a regular contract with us means you never have to worry about slimy cooling towers again. If you would like to know more, just get in touch with the team today.