What a season of bad indoor air costs a St. Augustine house, and the three questions worth asking before buying a fix
Bad indoor air in St. Augustine is rarely dramatic. It is a musty guest room, a child's inhaler, a thermostat set to 71 to feel dry. Those have a cost, and so does fixing them.
The cost of a damp, dusty season, without inventing numbers
Put the season in plain terms. A house that runs at 64 percent humidity from May to October grows mildew in closets and on the backs of dressers; somebody repaints or replaces what it ruins. A family with a kid who reacts to oak pollen buys medication from February to April and loses sleep. And the most common cost of all: a thermostat set three or four degrees lower than it needs to be, because cold air feels dry, which is paid to Florida Power & Light on every summer bill.
Against that, the equipment on this page costs something to buy and, in the dehumidifier’s case, a modest amount to run. We are not going to pretend to total it to the dollar. The honest statement is that for most St. Augustine houses built before 2000, the dehumidifier pays for its running cost by letting the thermostat come up, and everything else on the list is bought for health and comfort rather than payback.
Question one: does it make noise in a small house?
A 1,100 square foot cottage in Lighthouse Park has nowhere to hide a machine. Media filter cabinets, UV lamps and in-duct purifiers are silent; they sit inside the air handler’s airstream. A whole-home dehumidifier has its own fan and compressor; mounted in a garage or utility closet with a short duct, it is a low hum you stop noticing in a week. An energy-recovery ventilator is similar. Nothing on this list belongs in a bedroom closet, and we will say so if that is the only spot.
Question two: does it move the humidity, or just the dust?
Only one product on this page lowers humidity: the dehumidifier. Filters and purifiers do nothing for moisture. A ventilator, done right, keeps outdoor moisture from coming in but does not dry the house. If the complaint is sticky, musty, or a hygrometer in the 60s, start with the dehumidifier and stop reading about filters until that is done.
Question three: what does it actually remove?
- Media filter cabinet: pollen, dust, pet hair, most mold spores. The workhorse for the February-to-April pollen weeks.
- Whole-home purifier: finer particles, odors, the chemical smell of a renovated or brand-new Palencia house.
- Germicidal UV: keeps the coil and drain pan from growing the mold that causes the musty blast when the system starts.
- Dehumidifier: water. Which, in this climate, is the root of most of the rest.
- Ventilator: stale air in a house built too tight to leak, replaced with filtered outdoor air.
The order we would buy them in
For a leaky older house in Lincolnville, St. Augustine South or Davis Shores: dehumidifier, then a media cabinet, then UV. For a tight 2000s house in Murabella or a new build in Palencia: media cabinet, then a ventilator, then the purifier if the chemical smell lingers. For a beach rental: media cabinet and UV, with a dehumidifier if the readings call for it. Nobody needs all five on day one, and we will tell you which one your readings point at.
Air quality equipment questions, St. Augustine
My Uptown bungalow has plaster walls and a musty guest room. Which product goes in first?
A whole-home dehumidifier, before anything that filters. The mustiness is moisture; plaster and old wood hold it, and a closed guest room on an exterior wall is the dampest spot in the house. Dry it to 50 percent and the smell leaves. Then talk about filtration.
Will a whole-home purifier help with the oak pollen that coats everything in March?
The media filter cabinet does the pollen work; pollen is a large particle and a good filter catches it. The purifier earns its place on what the filter can’t catch: odors, volatile chemicals and the finest particles. Buy them in that order.
We rent our Vilano condo by the week. Which air product survives guests?
The ones guests can’t touch: a media cabinet at the air handler, UV at the coil, and a dehumidifier on its own control set to 50 percent. Avoid anything with a remote or a setting a renter can turn off.
Does any of this equipment run when the air conditioner is off?
A dehumidifier with its own controls and a ventilator do; they have their own fans. Filters, purifiers and UV lamps only work when the air handler is moving air, which is one reason a variable-speed blower that runs long and slow improves every one of them.
Want the air measured before you buy anything?
We bring a meter. The equipment conversation comes after the readings.