Comparison
APR Control and Hot Gas Reheat
Hot gas reheat and APR Control solve two different parts of the same problem, and they work well together. APR Control modulates the evaporator to the incoming reduced load so the coil keeps dehumidifying at part load; hot gas reheat manages the final discharge-air temperature to satisfy the space. Combined, they make an excellent dehumidifying unit, and where a project does not strictly require reheat, APR Control alone is often enough.
The bottom line
Depending on the application, APR Control in place of hot gas reheat is a viable path that plenty of customers have taken. Hot gas reheat is a proven, legitimate way to increase leaving-air temperature while dehumidifying. APR Control is not a replacement for it, it is a complement: APR Control handles the incoming reduced load on the evaporator and keeps the compressor modulating instead of cycling, while hot gas reheat manages discharge-air temperature to satisfy the space. Many customers run both together.
How they work together
Hot gas reheat and APR Control do two different jobs, which is exactly why they pair so well.
APR Control handles the load
As the load in the space drops, the suction pressure-activated valve modulates capacity so the compressor keeps running instead of cycling. The evaporator coil stays cold and keeps removing moisture through steady part-load operation, and the compressor is protected from short cycling and liquid floodback.
Hot gas reheat handles the air
Reheat re-warms the dehumidified air, often using hot discharge gas the system would otherwise reject, so the supply air leaves at the exact temperature the space needs. It is a proven way to hold a precise leaving-air condition.
Better together
Run together, as many customers do, the coil stays in a steady dehumidifying state with far fewer compressor starts, and the reheat coil trims the supply air to setpoint. The result is tight humidity control, comfortable supply air, and long, steady runtime: one excellent dehumidifying unit.
When APR Control can stand in for hot gas reheat
Where a precise, repeatable leaving-air setpoint is not strictly required, running longer at reduced capacity can do the dehumidification without a separate reheat step. A coil removes moisture only while it runs cold and wet, and ASHRAE-sponsored research has shown that cycling equipment re-evaporates moisture off the coil during every off-cycle and wastes minutes re-wetting the coil on each restart. By keeping the compressor running at part load, APR Control keeps the coil continuously draining condensate; a year-long field study on discharge-air modulation recorded 77% fewer compressor starts (Independent Field Study). In manufacturer lab testing, a coil under continuous modulation held leaving-air dew points of 39 to 43°F at typical comfort conditions, cold and wet enough to keep drying the air. In those applications, many customers have used APR Control in place of adding hot gas reheat, for a simpler unit that is in stock and ships fast.
Electric reheat is a different story
Electric, or resistance, reheat, common on VAV boxes, is a different animal. Instead of reusing heat the system already produces, it re-warms the air with pure electric heat, adding energy to the bill every hour it runs, on top of the cooling you already paid for. This is where APR Control is the clear efficiency play: by dehumidifying through longer part-load runtime, it can reduce or eliminate the need for electric reheat in many comfort applications, cutting that resistance-heat energy directly.
Where APR Control helps
- Complements hot gas reheat: APR Control carries the part-load dehumidification while reheat holds the leaving-air setpoint
- Cuts resistance-heat energy: reduces or eliminates the need for electric reheat in many comfort applications
- Compressor protection: guards the compressor against liquid floodback
- Evaporator freeze protection: capacity modulation holds suction pressure and temperature in a safe range
- Short-cycling protection: continuous part-load operation keeps the compressor running instead of cycling off
- In stock with a short lead time, so it does not delay the project schedule
- UL Listed, and backed by Rawal Devices Engineers who assess your equipment and application directly
Where precise dew-point control is required, hot gas reheat and the APR‑E Valve remain the right tools for holding a tight discharge-air setpoint. Every application is different, so our engineers review yours before making a recommendation.
Pair APR Control with your reheat design
Tell us your reheat setup and humidity target, and a Rawal Devices Engineer will show you how APR Control fits, whether alongside reheat or in place of it, on us, with a one-business-day response.
Talk to an Engineer[email protected] · 800‑727‑6447 · rawal.com