Can a leaking air conditioner actually start a fire?

Yes. When an AC drain pan overflows and water reaches nearby electrical equipment, it can short-circuit components and produce sparks that ignite insulation, wood, or stored combustibles. The National Fire Protection Association has tied thousands of U.S. home structure fires per year to air conditioning, fans, and related equipment.

What is a float switch on an AC and do I need one?

A float switch (also called a safety switch or water level switch) cuts power to your air conditioner if the drain pan fills with water. It is one of the cheapest and most effective protections against an AC-related water leak or fire. If your current system does not have one, an HVAC technician can usually add one as an inexpensive retrofit.

How do I keep my AC drain line from clogging?

Annual professional maintenance is the most reliable prevention. Between visits, you can pour a small amount of diluted bleach into the access port on the drain line to discourage algae and biofilm. Ask your HVAC technician to show you the correct port and the right amount for your specific system before attempting it yourself.

Is it safe to store boxes in my AC closet?

No. AC closets often end up holding combustibles like paper towels, holiday wrapping, broomsticks, and out-of-season clothing. If a drain pan overflows or an electrical component sparks, those items become fuel. Keep the AC closet clear and store flammable items elsewhere.

Why is AC drain pan overflow such a common problem in Florida?

Florida's high humidity means your AC pulls a large amount of moisture out of the indoor air, and that condensate has to drain somewhere. Combined with long cooling seasons that run most of the year, drain lines see far more water volume here than in most parts of the country, which is why algae clogs and pan overflows are so much more common in coastal Northeast Florida homes.

AC Safety Advice • Originally Published August 2014 • Updated May 2026

Leaky Air Conditioners Can Be a Fire Hazard

Well maintained, they are built to keep us cool. But if your air conditioner springs a leak, things can get fiery hot. According to a National Fire Protection Association report, air conditioning, fans, and related equipment were involved in upward of 7,400 reported U.S. home structure fires, which caused 29 deaths, 249 injuries, and $207 million in direct property damage in a single year. Over a one-and-a-half-year span, 215 such fires happened in Florida alone.

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How an AC Leak Starts a House Fire

These blazes often happen when leaking air handlers cause nearby electrical equipment to short circuit. Firefighters and air conditioning technicians will tell you that most homeowners fail to properly maintain AC drain lines. As a result, drain lines become clogged and drainage pans overflow.

If electrical equipment is located beneath the unit (as is the case in many smaller apartment, condominium, or beachside homes), condensation can drip on it, short-circuiting it and producing sparks that easily ignite nearby insulation, wood, or stored items. The result can be devastating, and in Atlantic Beach, Neptune Beach, Jacksonville Beach, and the surrounding coastal communities, the combination of constant humidity and long cooling seasons keeps drain pans working overtime.

How to Help Keep Your Home and Family Safe

Fortunately, there are several practical ways to reduce the risk of an AC-related fire in your home.

Do Not Store Combustibles in the AC Closet

If your AC unit is located in a utility closet, resist the temptation to use the same space for storage. Common items that get stored in these closets include combustibles like broomsticks, paper towels, toilet paper, holiday gift wrapping, and out-of-season clothing. Store them elsewhere.

Install and Maintain a Working Smoke Detector

A working smoke detector inside or directly outside the AC closet is one of the simplest safety upgrades you can make. Test the batteries twice a year (a good rule of thumb is when daylight saving time changes) so the alarm is ready if a slow-developing short circuit starts to smolder.

Keep Drain Lines Clear

Pouring diluted bleach into the drain line can prevent algae and biofilm from clogging it. Ask an HVAC professional to show you the proper way to do this on your specific unit. A clogged drain line is the number one cause of an overflowing drain pan, which is the number one cause of the short circuits that lead to AC-related fires.

Look for a Float Switch on Your Next System

When choosing a new air conditioning system, look for one outfitted with a float switch (sometimes called a safety switch or water level switch) that prevents drainage pans from overflowing by killing the power when the water level rises. If your current system does not have one, our technicians can add one as an inexpensive retrofit.

Schedule and Keep Annual Maintenance Appointments

Most importantly, schedule and keep annual AC maintenance appointments. Charlie's Tropic Heating & Air offers planned service agreements through our Comfort Club that include drain line cleaning, float switch testing, and a full safety inspection of the electrical components near your air handler.

Warning Signs of a Drain Line or Pan Problem

You do not have to wait for a fire to know something is wrong. Watch for these early signs of a drain pan or drain line failure:

Water stains on the ceiling below an attic-mounted air handler.
Standing water in or under the secondary drain pan.
Water dripping from the secondary drain line outside the home (that line is meant to be a last-resort overflow, and water coming out of it means the primary line is clogged).
Musty or mildew smell from the AC closet.
The system shuts off unexpectedly, which can mean a float switch has tripped because the pan is full.

Any of these is reason to call for service before the situation escalates from a leak into an electrical hazard.

Atlantic Beach, FL AC Maintenance

Schedule Annual AC Maintenance with Charlie's Tropic Heating & Air

Jacksonville Beach's Charlie's Tropic Heating & Air offers annual planned service agreements that help ensure your AC unit is safely and properly maintained. Call 904-867-8480 to get started.

Licensed in Florida (CAC1820218, CACA41190) • Bryant Factory Authorized Dealer • BBB Accredited • Family Owned Since 1998

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