Do Portable Air Conditioners Need Draining? What You Need to Know

If you’re thinking about buying a portable air conditioner, one question that often comes up is: where does all the water go?

Air conditioners don’t just cool the air. As warm air passes through the unit, moisture is also removed from it. That moisture has to go somewhere – but thankfully, with many modern portable air conditioners, you shouldn’t be constantly emptying a water tank.

Do You Have to Drain a Portable Air Conditioner?

In normal cooling mode, many modern portable air conditioners use a self-evaporating system.

This means much of the moisture collected from the room is evaporated and expelled outside with the hot air through the exhaust hose.

For everyday use, this can mean the unit runs for long periods without needing to be manually drained.

However, it doesn’t necessarily mean you’ll never have to drain it.

In particularly humid conditions, or when the air conditioner has been running for extended periods, water can collect inside the unit. If the internal reservoir becomes full, the unit may display a warning or stop cooling until the water has been drained.

How Do You Drain One?

Portable air conditioners normally have a drainage point towards the bottom of the machine.

The unit is switched off, the drain cap or plug is removed and the collected water is allowed to run into a shallow tray or suitable container.

It shouldn’t be something you need to do every day when using a correctly sized modern portable AC unit for normal cooling.

What About Dehumidifier Mode?

This is slightly different.

When a portable air conditioner is used in Dry or Dehumidifier mode, it can remove considerably more moisture from the air. Some models therefore allow a continuous drainage hose to be connected.

The hose is normally positioned so water can flow downhill by gravity into a suitable drain or container.

So Is Drainage Something to Worry About?

For most people using a portable air conditioner primarily to keep a bedroom, office, conservatory or living space cool, drainage shouldn’t be a major inconvenience.

The important thing is understanding the particular model you’re buying and checking whether it offers self-evaporation, a full-water warning and continuous drainage where required.

If you’re still deciding which type of unit is right for you, read our Portable Air Conditioner vs Air Cooler guide, our UK BTU sizing guide, and our guide to portable air conditioner window venting.

At UK Building Supplies, we’re expanding our range beyond traditional building materials to include practical products for keeping homes and workplaces comfortable throughout the year.

Keep an eye on our air conditioning range as new products become available.