Even in Florida, commercial buildings need heating — not for cold winters but for reheat: warming overcooled or dehumidified air back to a comfortable temperature, and handling perimeter zones on cool mornings. Heating hot water and reheat controls manage the heat source, reset the water temperature to demand, and modulate reheat coils — and done correctly, reheat is a necessary comfort and humidity tool, not the energy villain it is sometimes assumed to be.
Florida’s heating load is small, but it is not zero, and it is concentrated in reheat. A building that deeply dehumidifies its air — essential in this climate — cools that air below comfort temperature in the process, and reheat brings it back up. Perimeter zones on a 45°F January morning need heat too.
So the heating controls in a Florida building are mostly about reheat and shoulder-season comfort, served by a modest hot-water system, electric coils, or heat-pump heat.
The heat source might be condensing boilers, a heat-pump or heat-recovery chiller, or electric heat. Where there is a hot-water plant, the controls stage the heat source to meet demand — firing or staging only as much capacity as needed, respecting minimum run times, and protecting the equipment.
Because the Florida heating load is small and intermittent, efficient staging and avoiding short-cycling matter — the system spends much of its time at low load.
Like chilled water, hot water benefits from reset — but in the other direction. When heating demand is low, the water does not need to be as hot, so the controls reset the supply temperature down. Lower water temperature means less standby loss and, with condensing boilers, much higher efficiency (they condense and gain efficiency at lower return-water temperatures).
The reset tracks outdoor temperature or actual demand, keeping the water just hot enough to satisfy the neediest reheat coil. It is the heating-side reset strategy.
At the zone, reheat coils warm the air after the VAV box damper. The control modulates the coil — a hot-water valve or electric stage — to hold the zone at setpoint when it needs heat. The key is the sequence: the zone goes to minimum airflow before reheat engages, so the system is not cooling air centrally and reheating it locally any more than ventilation requires.
That coordination, defined in the VAV box sequence, is what keeps reheat from becoming waste.
Reheat gets a bad reputation because, done poorly, it means simultaneous heating and cooling. But in a humid climate, some reheat is genuinely necessary: dehumidification requires cooling air below comfort temperature, and that air must be tempered before delivery, especially to low-load and sensitive spaces.
The goal is not to eliminate reheat but to minimize unnecessary reheat — through good minimum-airflow settings, reset, and recovering free heat where possible. Good controls do exactly that.
Excess reheat is one of the most common and most expensive control faults — a stuck valve, a too-high minimum airflow, or a fighting heating and cooling loop can burn energy invisibly for months. Trending and fault detection are how it gets caught.
A zone simultaneously calling for cooling air and running its reheat coil hard is a classic flagged fault. See fault detection and trending.
Yes, mostly for reheat. Deep dehumidification cools air below comfort temperature, and reheat brings it back up; perimeter zones also need heat on cool mornings. Florida heating controls focus on reheat and shoulder-season comfort, served by a modest hot-water system, electric coils, or heat-pump heat.
When heating demand is low, the controls reset the hot-water supply temperature down, since the water need not be as hot. This reduces standby losses and, with condensing boilers, raises efficiency because they condense at lower return-water temperatures. The reset keeps water just hot enough for the neediest coil.
No. Done poorly it means simultaneous heating and cooling, but in a humid climate some reheat is necessary — dehumidification requires cooling air below comfort temperature, which must then be tempered. The goal is minimizing unnecessary reheat through good minimum-airflow settings, reset, and recovered heat, not eliminating it.
Through trending and automated fault detection. A zone simultaneously calling for cooling air while running its reheat coil hard, or a too-high minimum airflow forcing reheat, are classic flagged faults. Catching them prevents energy from being burned invisibly for months.
Suncoast Cold Systems installs, wires, and configures the HVAC controls integral to the mechanical systems we provide — and specifies open protocols (BACnet, Modbus, open supervisory platforms) so you own your building’s controls and data, with no proprietary dealer lock-in. Where a project calls for certified systems integration, we coordinate it within one accountable mechanical scope. Licensed Florida Class A Air Conditioning Contractor (FL #CAC1824642).