Using the correct air conditioner settings to avoid water damage at home

Air conditioners are essential for staying comfortable during warm weather—but if not used correctly, they can quietly contribute to water damage in your home. Whether you’ve noticed dripping near vents, musty smells, or unexpected damp spots, your A/C unit could be the culprit.

As a restoration company, we’ve seen firsthand how preventable water damage from air conditioning systems can turn into costly repairs. Here's how to avoid it.

1. Set Your Thermostat at a Reasonable Temperature

Setting your A/C to a very low temperature—especially on humid days—can cause the system’s evaporator coils to freeze. When that ice melts, it can overflow the drain pan or back up into your ducts and ceiling.

Tip: Keep your thermostat no lower than 20°C (68°F) if it’s especially humid, and avoid dramatic drops from outdoor temperatures.

2. Use the “Auto” Fan Setting Instead of “On”

Many thermostats give you the option to keep the fan running continuously (“On”) or only when the unit is actively cooling (“Auto”).

When set to “On,” the fan can blow moisture from the coils back into your ducts before it has time to drain, increasing humidity and risk of mold or water damage.

Tip: Use the “Auto” setting to allow the system to drain properly between cycles.

3. Ensure Your System Is Draining Properly

All air conditioners remove moisture from the air. That water should safely exit your home via a drain line or pump. But if the drain becomes clogged—or the pump fails—water can back up and cause damage.

What to check:

Is your drain line clear and angled properly?
Do you notice standing water near your indoor unit?
Is your drip pan cracked, rusted, or overflowing?

If you’re unsure, a routine HVAC inspection can prevent hidden issues from turning into emergencies.

4. Replace Filters Regularly

Dirty air filters restrict airflow, which can cause the coils to freeze over. That leads to the same issues mentioned earlier: melting ice, overflowing pans, and water damage.

Tip: Replace or clean your filters every 1–3 months, especially during peak cooling season.

5. Use a Dehumidifier in Damp Homes

If your home struggles with high humidity, your A/C may work overtime to cool the air, but not remove enough moisture. This can still lead to condensation on vents and walls.

Adding a standalone dehumidifier can reduce stress on your system and help protect your home from mold, mildew, and water staining.

Final Thoughts

Water damage from air conditioners is surprisingly common—and preventable. A few simple adjustments to your settings and regular maintenance can save you from a lot of stress (and repair bills).

If you’ve already noticed signs of water damage, musty odours, or mold around your A/C, don’t wait. Professional inspection and cleanup can stop the problem before it spreads.

Need help? Contact us for expert water damage assessment and restoration services. We're here when it matters most.