That is exactly the concern an ERV is built to answer, and it is the right question to ask in Florida. The energy recovery core transfers moisture between the outgoing and incoming air streams, so incoming air is preconditioned before it enters. Fresh air without an ERV — open windows, or exhaust fans pulling air through gaps — does import humidity. That is the difference.

Because they only push air out. Removing air without replacing it creates negative pressure, and the building draws replacement air in through whatever gaps it can find — wall cavities, attic spaces, around window frames. That air is unfiltered, uncontrolled, and in Florida, humid. An ERV supplies and exhausts at matched rates, so the pressure stays stable and the incoming air arrives where you intended.

Some, since you are conditioning air that was previously outdoors — we would not claim otherwise. The recovery core is what keeps that increase modest rather than severe, by preconditioning incoming air using the air on its way out. Compared with achieving the same ventilation by opening windows or running exhaust fans, an ERV is considerably the cheaper route.

Both recover heat; an ERV also transfers moisture. In cold dry climates an HRV often suffices because humidity control is a lesser concern. In Florida, moisture transfer is the whole point — managing what incoming air carries matters as much as its temperature. That is why ERVs suit this climate and why we install them here.

They solve different problems. Filtration removes particles from the air you have; purification treats contaminants in it; ventilation replaces the air itself. If your complaint is dust or allergens, the first two address it. If it is staleness, lingering odours, or the sense that the air simply never changes, no amount of filtering will fix that — because the air is clean but exhausted.

ERVs typically run continuously at a low rate, or on a controlled schedule, rather than cycling with the air conditioning. Controls are configured during installation to suit the property and how it is occupied. A holiday rental and a full-time family home have different ventilation needs, and the settings should reflect that rather than a factory default.