Why is my air conditioner leaking?

Even in record-breaking heatwaves, an air conditioner leaking water shouldn't be ignored. This expert advice guide helps you get to the root of the cause.

My air conditioner is leaking – why?

An AC unit leaking water is a nuisance and a telltale sign that it needs repairing.

Some of the most common reasons for an AC unit leaking water are:

• Clogged or disconnected drain line – leading to the drip pan backing up and leaking

• Damaged drain pan – over time, a plastic drain pan can develop cracks due to water filling up, changing temperatures, or improper installation

• Dirty filter – dust and dirt clog up the filter if you don't clean or replace it regularly

• Incorrect refrigerant levels – often caused by poor installation or maintenance

• Frozen, cracked or damaged evaporator coils – low refrigerant levels or unsuitable fan operation could be to blame

• Clogged condensation drainpipe – this narrow pipe can easily get clogged with mould or debris if not regularly cleaned, causing a backflow of water

Top tip – Newer air conditioning units will switch off automatically if a clog is detected. However, older units don't have such nifty functions. Therefore, maintaining your AC unit with regular services is vital.

We recommend getting your air con serviced at least once a year to ensure it's performing at its best. Our home air conditioning service cost guide provides more information about the costs.

Is an AC leak serious?

An air conditioner leaking water is more than just a slip hazard. If ignored, you could be facing a whole host of costly repairs and problems. Such as:

• Water damage – continuous water leakage could damage walls, ceilings, and floors, leading to costly repairs and potential structural issues

• Electrical hazards – water leaking onto electrical components within the AC unit could be a potential fire risk

• Mould growth – persistent moisture caused by the leaking water is a breeding ground for mould, causing respiratory health issues

• Musty smell – caused by a build-up of moisture and troublesome mould

• Reduced efficiency – leading to higher energy bills and insufficient cooling

• Costly replacements – you could be looking at replacing the unit if a leak is ignored and the unit is damaged beyond repair

How do you fix a leaking air conditioner?

Start by checking the air filter to rule this out. It might be time to clean or replace it.

This is a relatively straightforward task you can do yourself with the following steps:

1. Shut off the unit

2. Remove the vent cover – you might need to unscrew the vent cover to do this or use the cover release lever

3. Clean the cover

4. Hoover out the filter

5. Wash the filter in soapy water

6. Dry it thoroughly

7. Replace the filter securely

If your AC unit is still dripping after this step, it's time to call an expert. A reputable air con engineer will advise whether the unit needs to be repaired, or if it just needs a thorough cleaning with a professional service.

How to find a reputable air con engineer?

Ready to start your search for a professional to repair your leaking air conditioner? Follow these three simple steps:

• Use a professional directory

Make things simple by searching with a professional directory (like Checkatrade!). We're so confident in the quality of the trades on Checkatrade that if you book through us, we guarantee their work up to £1,000. Guaranteed for 12 months – Eligibility criteria and T&Cs apply.

Contact or pay a trade through Checkatrade and you’re covered by our 12-month guarantee of up to £1,000*

* Eligibility and T&Cs apply

• Read online reviews

A review from a previous customer is the greatest testament to a tradesperson's professionalism.

At Checkatrade, we check all online reviews to ensure they're from real people and that trades meet our high standards.

We check the reviews on Checkatrade are from real people, and that trades meet our high standards.

• Compare quotes

Get at least three quotes from experienced air conditioning specialists. That way, you can be sure you're getting the best tradesperson and price for the job. Search your postcode to get started.

How much does it cost to repair an air conditioner leaking water?

A leaking AC unit can be caused by several different issues. Therefore, the cost to fix it depends on what's causing the leak.

To give you a steer, an air conditioning engineer will normally charge between £30 - £60 per hourto service an air conditioning unit.

The refrigerant cost, if required, will be between £35 - £130.

You can learn more about the costs of an air conditioning service in our** home air con service cost guide.**

Key takeaways

• Don't ignore an air conditioner leaking water ­– it needs to be repaired

• Hire reputable professionals when a repair is needed – don't be tempted to cut corners and fix it yourself

• Remember to book an annual service for your AC unit

• Keep on top of cleaning your AC unit's filter in between services

FAQs

Should I turn off my AC if it's leaking?

Yes, switch off your air conditioning immediately. It's not worth the risk, no matter how tempting it may be to keep it running to beat the heat! Ignoring the problem will only cause more damage and land you with a hefty repair bill.

How do I stop my air conditioner from leaking water?

As mentioned earlier, it could be as simple as cleaning the filter. But for anything else, you'll want to hire an air conditioning expert to investigate the cause of the leak.

Is it safe to use a leaking air conditioner?

If ignored, a leaking AC unit can damage the internal electrical workings and pose a fire risk. Address the problem as soon as possible.

How long does an AC leak last?

Ignoring the problem won't make it go away. Your AC unit will continue to leak until it's fixed ­– or eventually packs in. The sooner you get it repaired by an experienced air con engineer, the better.