Living in Dunedin, we've got the best of both worlds: The charm of those 1920s bungalows near downtown and the sleek, modern builds popping up where old cottages used to sit. But when it comes to mold, Dunedin's coastal air doesn't quite care how much you paid for your granite countertops.
So, which is worse for mold, the "Old Florida" classic, or the brand-new construction home?
Dunedin's Landscape, Old vs. New
Dunedin is unique because our "median" home age is actually quite high: Most houses here were built in the '70s. We don't have the massive new-build tracts seen in Pasco County; instead, we have a lot of "infill" where a 1950s ranch was replaced by a more modern two-story.
Old Homes (Pre-1980s)
- Built to "breathe" — not airtight, which is extremely important as far as mold prevention
- Air moves through the walls, helping things dry out naturally
- More likely to show "obvious" mold from roof leaks or aging cast-iron plumbing
New Homes (Post-2010)
- Built like Tupperware — energy-efficient and almost airtight
- If moisture gets trapped inside, it has nowhere to go
- More likely to hide "systemic" mold behind drywall, out of sight
Why New Homes Fail
Most people think old homes are moldier because they're "musty." But new construction homes are often more at risk for hidden mold.
Because new homes are built so tightly that they rely entirely on the HVAC system to dehumidify. If your AC is oversized (a common mistake by builders hoping to ensure a house stays cool), it will short-cycle. Meaning, it cools the air down so fast that it doesn't run long enough to pull the moisture out of it. And you end up with a 72-degree home with 70% humidity. That's a recipe for a mold bloom on your furniture and baseboards.
"Construction moisture" is also very real. In Dunedin's rainy season, lumber sits out on job sites getting soaked. If builders wrap that house in stucco and vapor barriers before the studs are bone-dry, they're literally sealing mold into the skeleton of the new home.
Dunedin's Humidity Factor
Here's what relative humidity (RH) looks like in Dunedin throughout the year:
Dunedin's Relative Humidity, Season by Season
- Summer (June–Sept): Often sits between 75% and 90% — the danger zone.
- Winter (Dec–Feb): Drops, but rarely goes below 50–60%.
In an old Dunedin bungalow with single-pane windows, that 90% humidity is constantly trying to push its way inside, in what's known as "vapor drive." In a new build, that same humidity gets trapped inside by your morning shower and a pot of boiling pasta.
Which Is More Problematic?
Old homes are more likely to have "obvious" mold from roof leaks or plumbing failures in those aging cast-iron pipes.
New homes are more likely to have "systemic" mold — the kind that grows behind the drywall because the house is too airtight and the AC isn't calibrated for Dunedin humidity.
Pro Tips for Dunedin Homeowners
The 50% Rule
Regardless of the age of your home, buy a $10 hygrometer. If your indoor humidity stays above 55% for more than a couple of days, you have a problem brewing.
Don't "Set It and Forget It"
If you're heading out to the Dunedin Causeway for the day, don't turn your AC up to 80°F to save money. In Florida, the AC is a dehumidifier first and a cooler second. Keep it at 74–76°F to keep the air moving.
Check the Exterior "Saddle"
In older Dunedin homes, check the "saddle" — which is where the wall meets the floor on exterior-facing walls. If you see ghosting or dark spots, your wall is drinking in humidity from the outside.
Avoid Wallpaper
A big deal for Dunedin renovations: Never put vinyl wallpaper on (the inside of) an exterior-facing wall. It acts as a vapor barrier on the wrong side of the wall, trapping the humid Florida air that seeps through the stucco right against your drywall. Instead, stick to breathable, high-quality acrylic paint.
Whether you're in a 1925 Mediterranean Revival or a 2024 modern build, Dunedin's damp air is always looking for a place to settle. Keep it dry, keep it circulating, and don't let your "Tupperware" home suffocate.