What Are the Differences Between LGR and Conventional Dehumidifiers for Restoration?

When restoring a water-damaged building, choosing the right dehumidifier can significantly affect drying speed and the risk of secondary damage. The two main refrigerant-based options are LGR (Low Grain Refrigerant) dehumidifiers and conventional refrigerant dehumidifiers.

The main difference is simple: LGR dehumidifiers are designed to remove more moisture from already-dry air and achieve a lower dew point, making them particularly effective for professional water damage restoration. Conventional refrigerant dehumidifiers are generally better suited to maintaining moderate humidity levels and handling less demanding drying conditions.

What Is an LGR Dehumidifier?

An LGR dehumidifier is a high-performance refrigerant dehumidifier designed to produce very dry supply air.

LGR systems typically use a multi-stage refrigeration process. The incoming air is first precooled, allowing the refrigeration system to condense moisture efficiently. The air is then further processed before being reheated and discharged as warm, dry air.

This enables an LGR unit to continue extracting substantial amounts of water even as the restoration environment becomes progressively drier.

In practical restoration work, this is important because a conventional dehumidifier may perform well when the room is very humid but become less effective as the drying process continues.

What Is a Conventional Dehumidifier?

A conventional refrigerant dehumidifier removes moisture by cooling humid air below its dew point. Water condenses on the evaporator coil and is collected or drained away.

These units work particularly well in relatively warm and humid environments.

Conventional commercial dehumidifiers can be useful for:

Basements

Offices

Warehouses

Crawl spaces

Storage rooms

General humidity control

Mild to moderate water damage

However, their moisture-removal performance generally decreases as the surrounding air becomes drier.

LGR vs. Conventional Dehumidifiers: Key Differences

Feature	LGR Dehumidifier	Conventional Dehumidifier
Moisture removal	Very high	Moderate to high
Performance at lower RH	Excellent	More limited
Dew point	Lower	Higher
Drying speed	Faster for demanding restoration	Moderate
Water damage restoration	Excellent	Suitable for less severe cases
Energy consumption	Generally higher per unit	Generally lower
Portability	Common in professional restoration	Available in portable and fixed designs
Initial cost	Higher	Lower
Best use	Floods, major leaks, structural drying	Humidity control and lighter drying

The important distinction is not simply the number of pints or liters removed per day. An LGR's advantage becomes particularly apparent when the environment has already lost much of its moisture.

Why Are LGR Dehumidifiers Better for Water Damage Restoration?

After a flood or major leak, water can remain inside drywall, flooring, wood framing, insulation, furniture, and other porous materials.

Simply lowering the room's relative humidity is not always enough. Restoration equipment needs to create a strong moisture gradient so that water can migrate out of wet materials and evaporate into the surrounding air.

An LGR dehumidifier helps by maintaining a low-humidity and low dew-point environment.

The basic drying process is:

Wet materials → moisture evaporates into the air → LGR removes moisture → air becomes drier → more moisture evaporates from materials

This cycle continues until the materials reach an acceptable moisture content.

For professional restoration, LGR units are therefore frequently paired with air movers. Air movers increase airflow across wet surfaces, while the dehumidifier removes the moisture transferred into the air.

LGR Dehumidifiers Can Continue Working as the Building Dries

One of the biggest advantages of LGR technology is its ability to maintain strong moisture removal at lower humidity levels.

Imagine a water-damaged room that initially has extremely high humidity. A conventional refrigerant dehumidifier may remove a large quantity of water during the early stage.

As drying progresses, however, the room becomes progressively drier.

At this point, the conventional unit's moisture extraction rate can fall significantly.

An LGR unit is designed to perform more effectively under these increasingly dry conditions. This makes it particularly valuable during the later stages of structural drying, when removing the remaining moisture can be difficult.

Are LGR Dehumidifiers Always Better?

Not necessarily.

LGR does not mean that a unit is automatically the best choice for every application.

For everyday humidity control, a conventional commercial dehumidifier may provide better value.

For example, if a warehouse needs to maintain 50–60% RH throughout the year, purchasing an expensive LGR restoration machine may be unnecessary.

LGR equipment becomes more valuable when the priority is rapid and aggressive drying, especially after significant water intrusion.

Choose an LGR dehumidifier when:

A building has experienced flooding.

Large quantities of water have entered the structure.

Walls, floors, or ceilings have absorbed significant moisture.

Rapid drying is required.

The drying environment needs to reach a low dew point.

Professional restoration equipment is required.

Choose a conventional commercial dehumidifier when:

The main goal is long-term humidity control.

Moisture levels are moderate.

The building has relatively stable environmental conditions.

Rapid structural drying is not required.

Equipment cost and energy consumption are major considerations.

LGR vs. Conventional Dehumidifiers: Which Dries a Building Faster?

In demanding water damage restoration conditions, an LGR dehumidifier will generally dry a building faster than a conventional refrigerant dehumidifier.

However, drying speed depends on the entire restoration system.

Important factors include:

Initial material moisture content

Indoor temperature

Relative humidity

Air movement

Building construction

Amount of water damage

Vapor permeability of materials

Air leakage

Dehumidifier capacity

Number and placement of air movers

A high-capacity LGR operating without adequate air circulation may not outperform a properly designed system using both dehumidifiers and air movers.

The objective is therefore not simply to buy the largest dehumidifier. It is to create an effective drying system.

Can a Conventional Dehumidifier Be Used for Water Damage?

Yes. A conventional commercial refrigerant dehumidifier can be used for certain water damage situations.

It can be appropriate when:

The affected area is relatively small.

Indoor humidity is high.

The damage is limited.

Drying requirements are not especially aggressive.

The building has already undergone significant initial drying.

However, for severe flooding or professional structural drying, an LGR unit generally provides greater drying capability.

LGR Dehumidifier and Air Mover: The Standard Restoration Combination

The most effective restoration setup commonly combines dehumidification and air movement.

Air movers circulate high volumes of air across wet materials. This increases evaporation.

The LGR dehumidifier then removes the evaporated moisture from the air.

A simplified process looks like this:

Air mover → wet surface → moisture evaporation → LGR dehumidifier → dry air → air mover

This creates a continuous drying cycle.

Restoration technicians should also monitor temperature, RH, dew point, and material moisture content rather than relying solely on the amount of water collected by the dehumidifier.

How Do You Choose Between an LGR and Conventional Dehumidifier?

The best choice depends primarily on the severity and objective of the restoration project.

For a minor leak where the main requirement is to reduce elevated indoor humidity, a conventional commercial dehumidifier may be sufficient.

For flooding, major plumbing failures, roof leaks, or extensive structural water damage, an LGR dehumidifier is usually the more appropriate choice.

A useful rule of thumb is:

Conventional dehumidifier = general moisture control.
LGR dehumidifier = aggressive structural drying.

Frequently Asked Questions

Is an LGR dehumidifier better than a conventional dehumidifier?

For professional water damage restoration, generally yes. LGR units are designed to achieve lower dew points and maintain stronger moisture extraction as the drying environment becomes less humid.

What does LGR stand for?

LGR stands for Low Grain Refrigerant. The term refers to the unit's ability to produce very dry air with a low moisture content.

Can an LGR dehumidifier remove moisture from drywall?

Yes. An LGR dehumidifier can help dry moisture absorbed by drywall by lowering the humidity and vapor pressure of the surrounding air. Air movers are normally used at the same time to improve evaporation.

How long should an LGR dehumidifier run after water damage?

There is no universal number of hours. The unit should generally continue operating until moisture measurements show that affected materials have reached an appropriate drying level. Depending on the severity of the damage, this may take several days or longer.

Does an LGR dehumidifier replace air movers?

No. They perform different functions. Air movers accelerate evaporation, while the LGR dehumidifier removes moisture from the air. Using both together is usually more effective than relying on either one alone.

Is an LGR dehumidifier worth the cost?

For professional restoration and severe water damage, the higher cost can be justified by faster drying and stronger performance at lower humidity levels. For ordinary humidity control, a conventional commercial dehumidifier may be more economical.

Bottom Line

The fundamental difference between LGR and conventional dehumidifiers for restoration is their performance as the drying environment becomes progressively drier.

A conventional refrigerant dehumidifier is effective for general moisture removal and moderate drying. An LGR dehumidifier is engineered for aggressive moisture extraction, lower dew points, and demanding structural drying applications.

For flood restoration, major leaks, and water-damaged buildings, an LGR paired with properly positioned air movers is generally the stronger choice. For routine humidity control or less severe moisture problems, a conventional commercial dehumidifier can often deliver sufficient performance at a lower cost.