Ask any Southwest Florida home watch professional, including True North Home Watch in Naples, what does the most damage to empty homes, and few will say break-ins. The real culprit is quieter and far more common: humidity, which can build up quickly in a closed-up home when the A/C isn't running properly.
- True North Home Watch checks Southwest Florida homes by confirming the A/C is running and holding its set point, feeling the vents and looking for condensation at the air handler.
- Above roughly 60% relative humidity, mold and mildew begin to colonize drywall, grout, closets and the underside of furniture in a closed-up home.
- Do not shut the A/C off: most pros run it around 77-80 degrees F with the fan on auto, and a dry or dehumidify mode is better still.
- A failed A/C in a sealed house acts like a greenhouse, so leave interior doors and closets open and consider standalone dehumidifiers in problem rooms.
When a home is closed up for months with the A/C dialed back too far, relative humidity climbs. Above roughly 60%, mold and mildew begin to colonize drywall, grout, closets and the underside of furniture. By the time you smell it in the fall, it's already established.
What should you set the thermostat to in a vacant home?
The instinct is to shut the A/C off to save money. Don't. The goal is dehumidification, not cooling. Most pros leave the system running around 77–80°F with the fan on "auto," which pulls moisture from the air on each cycle. A "dry" or dehumidify mode is better still.
Why does a running A/C still need watching?
Here's the catch: an A/C that fails in July does the opposite of protecting your home — a stopped system in a sealed house becomes a greenhouse. That's why a home watch visit confirms the system is actually running and holding its set point. We check the thermostat, feel the vents, and look for condensation at the air handler.
Leave interior doors and closets open for airflow, and consider standalone dehumidifiers in problem rooms. But the single most important safeguard is trained eyes confirming, on a schedule, that your first line of defense is still working. See how it works or compare plans.