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Do Air Conditioners Use Water to Operate?

Air conditioners are a seemingly magical invention, and their value can’t be overstated in modern society. Despite being so common, many people have misconceptions about how they work.

Air conditioners like the ones in your home don’t use water, but commercial ones often do. The one in your home operates with a combination of compressors, fans, and evaporator coils. You can often see water near AC units due to humidity or as a waste product from the system.

This article will go more in-depth about how each of these air conditioners operates, as well as relevant topics such as why A/C units leak, how water is involved, and other types of cooling systems that do use water.

Residential Air Conditioners

There are a couple of types of these air conditioners, but the main two are HVAC, or central, and smaller room-based air conditioners.

At their essence, residential air conditioners suck air from your home into the unit, where it’s cooled and then pumped back into your house. 

Let’s take a closer look at the details:

  1. Air is sucked from your home into the system, typically via grates near the base or sides.
  2. The air flows over evaporator coils filled with flowing refrigerant. The refrigerant changes from liquid to gas easily, which means it absorbs heat – and absorbing heat is just another way of saying it makes stuff cold.
  3. The now-cold air is pumped into your home, and a compressor forces the coolant to change back to a liquid so it can cool more air. This produces heat, which is expelled outside with heat-dissipating fins.

Seems more or less easy to follow, right? Well, there’s a bit more to it depending on the exact kind of air conditioner – room based window units and car air conditioners work more or less the same, even if they’re powered differently. 

Large HVAC systems, or central air conditioners, involve a series of pipes to pump the cold air through your house. These central units are also equipped with heating elements that can warm your home during the winter months. 

These systems also come with a drainage line to dispose of the water pulled from the air during the cooling process. In contrast, the window units I mentioned before either feed the water back to themselves or drip onto the ground outside.

Air-cooled air conditioners are more efficient for personal use than commercial because they don’t require water to work, but they do make water as a waste product.

Commercial Air Conditioners

On the flip side of keeping your day comfortable, places like offices and stores often use air conditioners that work differently from your home unit.

While residential units are considered air-cooled, commercial units are called water-cooled. This is because of the greater energy efficiency of cooling with water – and they work better in hot areas for this reason.

2 types of Water-Cooled Systems 

  • Cooling tower: These air conditioners use a large tank to cool a constant stream of water, which cools the air within the system by using fans. A downside of this is that water has to be periodically added to keep it running. Cooling tower systems are used by shopping malls, power plants, and other large scale businesses.
  • Chiller: These are the closest thing to a residential AC. Chillers compress water and coolant that flows through pipes to coils near fans. This fan system delivers cold air to the building.

As you can see, there are wildly different ways that businesses cool their air, especially compared to home-based systems. 

Water-cooled systems use a lot of water, making them inefficient, and they require more maintenance and upkeep than air-cooled units. You should always be sure not to add more water to your water-cooled system unless told to by a professional, as this can greatly cut your air conditioner’s efficiency.

Thanks to recent advances in technology, these are not the only options. The following are also now available if they suit your needs better:

  • Air-cooled air conditioners suitable for commercial use
  • Small and portable water-cooled air conditioners for your home

Why Is There Water Coming Out of My Air Conditioner?

If you thought that air conditioners used water, it may be because you’ve seen water around or coming out of yours. 

When the water in the air is compressed by the air conditioner, it sheds water in a liquid form. Different systems use or dispose of this water in different ways. You should always be sure that your air conditioner is running properly, and that means checking that there aren’t any leaks inside your home. If there are leaks inside your home, this typically indicates a problem you most likely need a professional to fix. 

Room-based window units often drip water out of the back, which is normal. Some of them feed the wastewater back to themselves to use in their evaporative coils. In either case, you shouldn’t see water in your home. So if you see any, you should call a professional to come check out why it’s leaking inside your home. 

The water produced by portable air conditioners isn’t considered safe to drink, but many people repurpose it for gardening or other tasks to maximize efficiency. However, do not use the water at all if there’s a possibility it’s been contaminated by chemical-based cleaning products. Instead, discard the water safely away from plants. As the chemicals could damage your plants and other things.

Central units generally have a drainage line and dispose of water automatically. If the line gets clogged, it can cause water to build up and leak inside your home. If this happens, you should contact HVAC professionals to come clean the line for you as soon as possible to prevent water damage to your home. 

Alternatives to Air Conditioning

Some people choose not to use air conditioning, perhaps due to cost or inefficiency in their disposal of water. There are many other alternative methods to stay cool you can use, but they wouldn’t really be useful for commercial applications – stick to your home if you want to try any of these methods:

  • Cooling vests are a product that you soak in water and wear to stay cool. More expensive models even utilize chemical coolants flowing through them.
  • Fans are a popular alternative to air conditioning. They keep you cool by blowing away the hot air your body naturally produces, letting cold air take its place. Fans have the advantage that they use a tiny fraction of the electricity air conditioners do, potentially saving you a lot of money.
  • Evaporative coolers, aka swamp coolers, are a powerful and cheap alternative to air conditioners. They work by air passing through a wet area, causing the air to evaporate water, which cools that air. Homemade variations only use electricity in a fan, while commercial evaporative coolers use a more complex system for better results. 

Obviously, air conditioning gives better results than these options, but you could consider them if concerned about your power bill.

Final Thoughts

Air conditioners are a marvel of modern engineering, though not everyone knows that most residential models don’t use water to run. We learned about different principles of various air conditioners, how water is used by and created by them, and even some alternatives to air conditioning.

While air-cooled AC units dominate as far as residential uses go, water-cooled units are the norm in commercial applications. However, alternatives for both now exist. Be sure to do thorough research when considering any air conditioners for your home or business.

Finally, if you’re considering a cooling solution that doesn’t use as much electricity as AC units, you have a plethora of cheap and easy options to choose from as well – from cooling vests to evaporative cooling, modern technology ensures you don’t have to stay hot.


  • Chris Hewitt

    Chris is a Texas-based freelance writer who loves the outdoors and working in his garage. When he's not enjoying the Texas sun, he can be found tinkering with all sorts of things in his workshop.

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