Quick answer
A refrigerant dehumidifier removes water by chilling air on a cold coil until vapor condenses, while a desiccant dehumidifier removes it by passing air over a drying material that adsorbs the vapor and is then heated to release it.
Both lower the humidity of the air so wet materials can dry. They differ in what they need: the refrigerant type works best in warm, humid air, and the desiccant type is described as keeping its performance in cold or very dry conditions.
Quick facts
The key facts about Refrigerant vs. Desiccant Dehumidifier, with sources:
- Refrigerant method
- A cooling coil whose surface is below the air’s dew point, so vapor condenses on it 1
- Desiccant method
- A rotor of desiccant material adsorbs vapor, then hot air regenerates it 1
- Refrigerant cold limit
- Frost can form on a household unit’s coils in spaces below 65°F; one restoration model lists 33°F to 100°F 25
- Desiccant range
- One manufacturer describes the wide operating range and ultra-low grains of a desiccant 3
- Airstreams
- A desiccant unit has separate process and regeneration airstreams 3
- Printed rating example
- A desiccant spec sheet lists 118 pints per day at 80°F and 60% RH, with 395 CFM of process air and 65 CFM of reactivation air 4
- Low-grain refrigerant rating
- One refrigerant model lists 8 pints per day at 80°F and 20% RH 2
Key takeaways
- A refrigerant dehumidifier cools air on a coil until water condenses. A desiccant dehumidifier uses a drying material instead 1.
- Cold coils can frost, so refrigerant units lose output in cold spaces. One restoration model lists 33°F to 100°F and shuts off at low inlet temperature 2.
- A desiccant unit runs two airstreams, one that dries the room air and one that reheats the desiccant. That second stream has to be ducted away 3.
- Neither type fixes a leak, removes mold or makes a space safe. Both lower humidity so materials can release water.
- The right choice depends on temperature, humidity and the job. Ask the company why it chose each machine on yours.
Two ways to take water out of air, in plain English
Every dehumidifier has the same goal: lower the water vapor in the air so wet materials can give up moisture. The two types do it differently. Our dehumidifier page covers the basics. This page covers the choice between the two.
A refrigerant unit cools the air. A research review from the University of Missouri and North Carolina State University, hosted by the U.S. Department of Energy, describes the cooling coil as a surface that must be below the dew point of the air to handle the moisture load 1.
Water condenses on the cold surface and is drained away. ENERGY STAR describes household units this way: refrigeration coils, a compressor and a fan, with a humidistat that cycles the unit 5.
A desiccant unit absorbs the water on a material instead. The same review describes a desiccant wheel as a rotor that holds a solid desiccant material.
As the wheel rotates, the desiccant adsorbs vapor in one part and releases it in another, and hot air is used to regenerate the material 1.
A manufacturer’s manual for a desiccant dehumidifier describes separate process and regeneration airstreams 3.
Which one is on your job depends on temperature and humidity more than on brand. Our psychrometrics page explains the air readings that drive that choice.
How each one works, step by step
The two cycles are shown separately. The refrigerant steps come from ENERGY STAR, a manufacturer’s manual and the DOE-hosted review. The desiccant steps come from the review and a manufacturer’s manual 5213.
- Refrigerant: air is drawn in. A fan pulls room air through a filter and over the coil 52.
- Refrigerant: vapor condenses. The coil surface is below the air’s dew point, so water forms on it and drains out 1.
- Refrigerant: the coil is defrosted. Ice can form on cold coils, and the model in the manual runs a defrost cycle to clear it 2.
- Desiccant: process air passes the wheel. The desiccant adsorbs vapor from the room air, which leaves drier 13.
- Desiccant: a heated stream regenerates it. Hot air passes through another section of the wheel and drives the water out, while the wheel turns 1.
- Desiccant: the wet exhaust is ducted away. The manual describes the regeneration air as an isolated stream sent through supplied flex duct 3.
Refrigerant
- Cold coil below the dew point
- Water condenses and drains
- Coil can frost in cold air
- Defrost cycle clears the ice
Desiccant
- Rotating desiccant wheel
- Water is adsorbed, then driven out by heat
- Two airstreams: process and regeneration
- Regeneration air is ducted away
Both end with drier air in the room. The path to get there is different. Source: [1] [5] [2] [3]
Refrigerant and desiccant compared, feature by feature
| Feature | Refrigerant (example model) | Desiccant (example models) |
|---|---|---|
| Removal method | Cold coil; vapor condenses 1 | Desiccant wheel adsorbs vapor; heat regenerates it 1 |
| Airstreams | One main air path through the coil 2 | Separate process and regeneration airstreams 3 |
| Temperature behavior | Listed range of 33°F to 100°F; shuts off below 45°F inlet and restarts at 50°F 2 | Described as having a wide operating range 3 |
| Printed rating at 80°F and 60% RH | 70 pints per day (LGR 130) 2 | 118 pints per day (DriTec 4000i) 4 |
| Low-humidity rating | 8 pints per day at 80°F and 20% RH 2 | Described as providing ultra-low grains 3 |
| Process and reactivation air | Process air up to 195 CFM 2 | 395 CFM process and 65 CFM reactivation (DriTec 4000i) 4; 385 CFM process (D385) 3 |
| Drain | Pump and drain hose for the condensate 2 | Wet exhaust stream is ducted via supplied flex duct 3 |
Pints per day are not a quality score
The two ratings above are for different models of different sizes at the same stated condition. They show how a rating is printed, not which type is better. Compare machines only at the same conditions and for the same space.
Example: reading the airflow numbers on a desiccant spec
A desiccant machine has two airflows on its spec. The arithmetic below uses the printed numbers for two models and divides them. The division is our own, shown to explain the numbers, and does not rate either machine 43.
| Model and printed spec | Process air | Reactivation air | Reactivation as a share of process air |
|---|---|---|---|
| DriTec 4000i (Dri-Eaz spec sheet) | 395 CFM | 65 CFM | 65 ÷ 395 = about 16.5% |
| Phoenix D385 (Therma-Stor manual) | 385 CFM | 75 CFM | 75 ÷ 385 = about 19.5% |
Two lessons follow. First, the dry air that goes to the room is the process stream, which is the larger one, and the smaller reactivation stream is the one that carries the removed water away. Second, that smaller stream must have somewhere to go.
The D385 manual supplies flex duct for it and describes it as isolated from the drying chamber 3. When a desiccant unit is in your house, ask where its exhaust is going.
Where you see each type on a job
In a warm, humid, heated house. This is where refrigerant units are usual. The manual’s listed range of 33°F to 100°F is the kind of window they are built for 2.
In cold or unheated spaces. Crawl spaces, unheated basements, garages and winter jobs are where a desiccant unit may be chosen, because it is described as having a wide operating range 3.
In very dry air. A desiccant unit is described as providing ultra-low grains 3, while the refrigerant model lists only 8 pints per day at 80°F and 20% humidity 2.
On the drying log. The moisture log records daily air readings with the material readings 8. Either type should show up by model in the equipment list, and our structural drying page explains how it is used.
Ask why that machine is in your house
A good answer names the temperature and humidity of the space and why the machine suits them. “It is what we had on the truck” is not one.
Strengths and trade-offs of each type
Where each is strong
- Refrigerant: familiar, drains condensate through a hose or pump, and is built for warm, wet air; one model rates 135 pints per day at 90°F and 90% 2.
- Desiccant: described as having a wide operating range and ultra-low grains 3.
- Desiccant: research describes desiccant systems as thermally driven and reliable over a wide range of operating conditions 1.
- Refrigerant: the same unit can serve a household or restoration role, with efficiency tracked by ENERGY STAR for household models 5.
Where each is weaker
- Refrigerant: frost can form on the coils in spaces below 65°F, which hurts performance 5, and output drops sharply in dry air 2.
- Desiccant: needs a second airstream that must be ducted away, and the wheel has to be heated to regenerate 31.
- Both: neither fixes the source of water or cleans contamination.
- Both: ratings only mean something at stated conditions 24.
Limits of this comparison
We loaded manuals and spec sheets for specific models, not a neutral test comparing the two types. Statements about each type here describe those models and the research review, and other models differ.
The review we used is about desiccant materials in building air conditioning.
It notes that commercial viability of desiccant-based systems has been hampered by obstacles including maldistribution of airflow and material properties that limit adsorption and regeneration rates and make systems bulky or costly 1.
That finding concerns research systems, not the restoration machines on your job.
We could not load a manufacturer white paper that defines “LGR” in general terms, so this page makes no claim about what separates an LGR unit from any other refrigerant unit beyond what its own manual states 2.
We also could not confirm that a refrigerant model is cheaper or faster than a desiccant one. No source we loaded says so, and the answer depends on the space, the conditions and the equipment. Neither type decides when drying ends. Readings against a goal do 8.
What drives the cost of each, without prices
We publish no prices, no rental rates and no model costs. The sources we loaded give none, and any number would be invented. We can name the cost drivers on a drying job instead.
For both types, the equipment line is machine count times days. For a refrigerant unit, cold air and dry air cut output, so a cold job may need more units or more days, or a switch of type 52.
For a desiccant unit, the cost drivers include its heater, its second airstream and the ducting to carry it away 3.
Life and warranty come from the maker, and the refrigerant manual asks for a filter check before each use, coil checks monthly and a pump inspection annually 2. For how equipment enters an invoice, see the cost guide, and use the drying time tool to see what affects duration.
How the choice is made and what you can do
The restoration company chooses equipment. You can ask good questions. No permit is normally needed for portable equipment.
- Ask the company to read the temperature and humidity of the drying area and outdoors, and write them on the log 8.
- Ask which type of dehumidifier is planned and why it suits those readings.
- If the space is cold, ask whether a refrigerant unit will keep working, given its listed range 2.
- If a desiccant unit is used, ask where the regeneration air will go. The D385 manual ducts it through flex duct 3.
- Ask how many machines are planned and what the daily inlet and outlet readings will be.
- Check on day two. If the room is not drying, ask whether the type, the airflow or the number of units needs to change.
Keeping either type working
- Refrigerant units. The manual calls for checking the filter before each use, cleaning the coils monthly when visibly dirty and servicing the pump yearly 2.
- Both types. Keep the drain or duct path clear and do not run the machine in dusty work such as sanding 2.
- Desiccant units. Use the supplied duct and keep the regeneration path unobstructed 3.
- After the job. Keep indoor humidity below 60%, ideally 30% to 50%, as EPA advises 6.
- Use only the maker’s parts. The manual warns against modification or unapproved parts 2.
Warning signs the wrong type or a poorly set-up unit is running
- Little water and damp air in a cold room. A refrigerant unit may be frosting or shutting off 52.
- A desiccant unit with exhaust blowing into the drying space. The regeneration stream is isolated from the drying chamber by design 3.
- Humidity that stays high. A cause may be poor air movement, a leak, or an undersized unit 2.
- Heat or fumes from equipment. Unplug and call the company.
- Tripped breakers. Drying equipment can load a household circuit, and a technician should plan the circuits.
Electrical, heat and refrigerant hazards
Refrigerant models carry a warning for explosion or combustion from flammable refrigerant, and the maker says not to service the refrigeration system or use the unit near open flames 2. Desiccant units use heaters, so keep clearances. Never enter a flooded or fire-damaged building before it has been judged safe.
Standards, listings and guidance
Restoration standard. ANSI/IICRC S500 covers psychrometry and drying technology. The IICRC lists the fifth edition as the 2021 edition and says a revision is under way 9. It is voluntary and purchased, and its choice of dehumidifier type is not reproduced here.
Household efficiency. ENERGY STAR certifies household dehumidifiers by integrated energy factor. It describes refrigeration-based units and does not cover restoration desiccant machines 5.
Safety. The refrigerant model’s manual states certification to UL 60335-1 and 60335-2-40 and the Canadian equivalents 2. That covers the machine’s safety design.
Humidity guidance. EPA’s guideline is below 60% indoor humidity, ideally 30% to 50%, and drying water-damaged areas within 24 to 48 hours 6.
Your contract. Equipment choices may be the company’s call, and wording varies. Read the work authorization.
Compared with related equipment
| Equipment | What it does | How it differs |
|---|---|---|
| Refrigerant dehumidifier | Condenses vapor on a cold coil 1 | Best in warm, humid air; frosts when cold 5 |
| Desiccant dehumidifier | Adsorbs vapor on a heated wheel 1 | Two airstreams; described as wide-range 3 |
| Air mover | Forces air along floor and wall surfaces 8 | Moves air; does not remove vapor |
| Air scrubber | Filters particles from the air | Cleans particles; does not dry |
| Air conditioner | Cools air; EPA suggests it for humidity 6 | Built for comfort; a dehumidifier targets moisture |
Common myths about the two types
- Myth Desiccant is better.
- Reality The sources we loaded do not rank them. Each model has a listed range and rating, and the right choice depends on the space 23.
- Myth A refrigerant unit works the same anywhere.
- Reality ENERGY STAR notes frost can form on coils below 65°F, and one restoration model shuts off at low inlet temperature 52.
- Myth A desiccant unit makes the room hotter for no reason.
- Reality Its regeneration airstream is heated and isolated from the drying chamber and ducted away by design 3.
- Myth LGR is a different technology from refrigerant.
- Reality The manual for the LGR model we loaded describes a refrigerant system with coils and R32 refrigerant 2.
- Myth A bigger pints-per-day number means a better unit.
- Reality Ratings depend on conditions; one model lists 135, 70 and 8 pints per day at three conditions 2.
Climate decides which type fits
The regional variable is temperature. In warm, humid parts of the country, outdoor dew points above 70°F through most of a typical year make dehumidification, not ventilation, the main lever 7.
In cold regions, unheated spaces fall below the comfort range of refrigerant units: ENERGY STAR notes frost on coils below 65°F in a household unit, and one restoration model shuts off at 45°F inlet air 52.
A desiccant unit is described as having a wide operating range 3. Maximum use altitude for the refrigerant model is listed as 10,000 feet 2. Winter jobs in northern states are therefore where the question arises.
When the choice matters, and what to do next
The choice matters when the space is cold, when the air is very dry and materials are still wet, and when a refrigerant unit is running but readings stall. It matters less in a warm, ordinary room.
The next step is to ask the company for the air readings and the reason for its choice. Read how restoration works for the normal sequence of a job, and the company selection guide for more questions.
- If Warm, humid air in a heated house
- Then A refrigerant unit is the usual fit
- If Cold or unheated space
- Then Ask whether a desiccant unit is planned
- If Very dry air but materials still wet
- Then Ask what the dehumidifier is rated at that condition
- If Readings stall with one type running
- Then Ask whether the type or the airflow should change
Questions about Refrigerant vs. Desiccant Dehumidifier
What is the difference between refrigerant and desiccant dehumidifiers?
A refrigerant unit chills air on a cold coil so vapor condenses and drains away.
A desiccant unit passes air over a drying material that adsorbs vapor, then heats that material to release the water in a separate airstream. A DOE-hosted research review describes both mechanisms.
The right one depends on the temperature and humidity of the space.
Which dehumidifier works better in cold weather?
Desiccant units are described as having a wide operating range, per one manufacturer’s manual.
Refrigerant units lose output in the cold: ENERGY STAR notes frost can form on household coils below 65°F, and one restoration model lists 33°F to 100°F and shuts off at low inlet temperature. Ask the company which type it plans for a cold space.
Is an LGR dehumidifier a refrigerant dehumidifier?
The manual for the LGR model we loaded describes a refrigerant system with R32 refrigerant, coils and a defrost cycle.
LGR is a manufacturer label, and the sources we loaded do not give a general definition.
If it matters, ask the company to name the machine and show its rating at the conditions in your house.
What does a desiccant dehumidifier do with the water it removes?
It drives the water out of the desiccant with heated air in a separate regeneration airstream, and that moist air has to be ducted away.
A manual for one model describes the regeneration stream as isolated from the drying chamber and supplied with flex duct. Ask where the exhaust of any desiccant unit in your house is going.
Are desiccant dehumidifiers more expensive to run?
The sources we loaded do not give running costs and none should be assumed. A desiccant unit uses a heater to regenerate its wheel, and a research review notes regeneration rates and costs as obstacles for desiccant systems. Ask the company how it chose the unit and how long it expects to run it.
Can I use a desiccant dehumidifier instead of a refrigerant one?
In some conditions, yes, but that is the restoration company’s decision, based on air readings and the space. Desiccant units are described as suited to wide ranges and ultra-low grains, while refrigerant units are built for warm, humid air. Ask for the temperature and humidity readings that led to its choice.
What do pints per day mean on a dehumidifier?
Pints per day is how much water a unit removes from air in 24 hours at stated temperature and humidity.
One refrigerant model lists 70 pints at 80°F and 60%, 135 at 90°F and 90% and 8 at 80°F and 20%. A desiccant spec sheet lists 118 at 80°F and 60%. Compare ratings only at the same conditions.
Do I need both kinds on one job?
Sometimes, but the sources we loaded do not set a rule. A research review describes combining desiccant wheels with vapor-compression cooling in building air conditioning so each handles a different load. For a restoration job, the company decides from air readings and equipment on hand. Ask what each machine is doing.
How do I know the dehumidifier is working?
Look at the readings, not the noise. Many units display inlet and outlet temperature and humidity, and a grain depression. Your company should record daily air readings and material readings against the goal. If a room stays humid, a manual lists a full filter, clogged coils, a cold room or poor air movement as causes.
Is IICRC S500 clear on which type to use?
The IICRC’s public page lists psychrometry and drying technology among the topics the standard covers, but it does not state a choice. The standard is purchased, so this page does not reproduce it. Ask the company how it chooses equipment and request its daily air readings in writing.
Sources
- Mohammed, Ahmadi, Ma and Bigham, Desiccants enabling energy-efficient buildings: A review (accepted manuscript, DOE OSTI), retrieved .
- Legend Brands (Dri-Eaz), LGR 130 Dehumidifier Owner’s Manual #108997, retrieved .
- Therma-Stor Products Group, Owner’s Manual: Phoenix D385 desiccant dehumidifier (TS-387, revised 7/07), retrieved .
- Dri-Eaz (Legend Brands), DriTec 4000i Desiccant spec sheet (11-14-2019), distributor-hosted copy, retrieved .
- ENERGY STAR, Dehumidifiers (product guidance), retrieved .
- U.S. EPA, A Brief Guide to Mold, Moisture and Your Home, retrieved .
- U.S. EPA, Moisture Control Guidance for Building Design, Construction and Maintenance (EPA 402-F-13053, December 2013), retrieved .
- National Institutes of Health, Moisture and Mold Remediation Standard Operating Procedures (2023), retrieved .
- IICRC, ANSI/IICRC S500 Standard for Professional Water Damage Restoration (standard page), retrieved .
Expert review
Written by the HyreRestore Research Desk. Not yet reviewed by an outside expert. We say so rather than imply a review that has not happened; see our editorial policy.
How the numbers were checked: The mechanisms were read from a DOE-hosted research review of desiccant systems, ENERGY STAR’s dehumidifier page, one refrigerant restoration manual (Dri-Eaz LGR 130), one desiccant owner’s manual (Therma-Stor Phoenix D385, 2007) and a Dri-Eaz DriTec 4000i spec sheet copy.
Statements about each type describe those documents and are not a neutral test of the two types. The reactivation-share arithmetic is the Research Desk’s own division of printed figures.
A manufacturer white paper on LGR design, the full DriTec manual and a Condair brochure could not be loaded, so no general claim is made about LGR design, running cost or speed. DOE’s Energy Saver dehumidifier page returned an error. No prices and no durations are given.
Suggest a correction. We fix errors and say what changed.