Humidity control · Refrigerant or desiccant, rated capacity and dew point
A refrigerant dehumidifier condenses water on a cold coil; a desiccant dehumidifier adsorbs it on a rotor and drives it off with heat. Which one fits depends on the dew point you must reach and how cold the air is, and a capacity figure means little until you know the temperature and humidity it was measured at.
Refrigerant (compressor) and desiccant-rotor dehumidifiers for factories, warehouses, cold stores, pools, grow rooms and process rooms, as standalone or ducted units. Plastics resin dryers, compressed-air dryers and electrical-cabinet Peltier units are outside this page.
CNFX editorial research · Sources checked October 11, 2026 · 5 sources
Choose refrigerant or desiccant by dew point and air temperature
In a Consulting-Specifying Engineer roundtable, engineers explain that cooling-based dehumidification chills air below its dew point and then reheats it, while desiccant dehumidification removes moisture by adsorption driven by vapour-pressure difference. One engineer says "Desiccant dehumidifiers are most effective when the supply air temperature to a space is below 40°F dew point" (about 4 °C), where they avoid condensate freeze-up on a cooling coil. [1]
Cooling-reheat systems have lower first cost and work well above a 40 °F dew point; one engineer notes cooling coils struggle to get below about 45 °F with DX, 42 °F with chilled water and 38 °F with chilled glycol, while "most comfort applications require supply air dew-point temperatures between 50°F and 60°F". [1]
Desiccant regeneration needs high temperature heat; the same roundtable calls its coefficient of performance "inefficient, typically less than 0.6" and notes the dried air leaves warm, adding cooling load. In hybrid units, "The cooling coil removes most of the water from the air via condensation" and a desiccant rotor finishes the job with low-grade heat. [1]
Tell the supplier the room temperature and the humidity or dew point you must hold, the moisture sources (people, open doors, wet product, outside air) and the room volume. Type and size follow from the moisture load and the target dew point.
02
Compare capacity only at stated test conditions
ENERGY STAR explains that capacity is the water removed in 24 hours at test conditions, and that the US DOE moved portable dehumidifier testing from 80 °F to 65 °F to reflect basement conditions; there is less water to remove in cooler air, so the same unit reports a lower capacity. Its rough correlation puts an old 50 pints/day rating at about 30 pints/day under the new test. [2]
Editorial calculation: 30 US pints is about 14 litres, and 50 pints about 24 litres. Because rated capacity depends on the test conditions, a figure in L/day or pints/day is only comparable when the test temperature and relative humidity are stated.
ENERGY STAR also notes that the efficiency metric, Integrated Energy Factor, expresses litres of water removed per kWh and includes energy used while the unit is cycled off. Ask suppliers which standard and conditions their capacity and energy figures follow. [2]
03
Plan for desiccant reactivation and airflow
The roundtable explains that a desiccant rotor needs heat to drive off the adsorbed water, from a gas burner, recovered condenser heat or building exhaust air, and that rotary wheels need two airstreams, which increases unit size and weight. [1]
Ask the supplier for the reactivation heat source and power, the process and reactivation airflows, where the wet reactivation air is discharged, and the outlet dew point at your inlet conditions.
04
Compare what suppliers offer
Suppliers linked to this page list portable, floor-standing, ceiling-mounted, pool and desiccant rotor dehumidifiers for warehouses, grow rooms, food plants and battery dry rooms. [3][4][5]
Ant lists refrigerant units named from 38 L to 720 L, a choice of R410A, R32 or R290 refrigerant on its 90 L portable unit, and desiccant units up to 10,000 m³/h; TOJJE lists ceiling units of 230–500 pints/day and industrial units of 480–960 L/day plus a rotary desiccant unit; East lists condensing, desiccant rotor and hybrid units. None of these headline capacities states test conditions on the summary pages, so ask for them. [4][5][3]
05
Trace the dehumidifier components
This is a functional reference built from the sources cited; it is not one maker's parts list.
Fill the specification fields with values for your space
A dehumidifier quotation needs values for your space and process. The table explains each field, gives published values where a reviewed source states them, and says what to obtain from the supplier.
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
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Compiled and source-reviewed by the CNFX editorial team.
Published product pages show what a company offers, not tested performance. Confirm the legal seller, factory and scope for your order. How we source and review
· Page last updated 13 October 2026
Buyer questions
When should I use a desiccant dehumidifier instead of a refrigerant one?
When the supply air must reach a dew point below about 40 °F (4 °C), where cooling coils freeze up; above that, the roundtable says cooling-based systems with reheat "have a lower first cost". [1]
Why do two dehumidifiers with the same pints-per-day rating perform differently?
Capacity depends on test temperature and humidity; DOE now tests portable units at 65 °F instead of 80 °F, which gives lower ratings. [2]
How much energy does a desiccant dehumidifier use?
Reactivation heat dominates; one engineer calls the process COP "inefficient, typically less than 0.6", and the dried air leaves warm. [1]
Sources and what still needs a direct check
Sources checked 2026-10-11. ENERGY STAR (US EPA) explains DOE dehumidifier capacity and efficiency ratings. Consulting-Specifying Engineer published a roundtable of HVAC engineers comparing desiccant and cooling-reheat dehumidification. Supplier pages describe their own offers.
