LGR vs Standard Compressor Dehumidifiers: Key Differences

What is an LGR dehumidifier?

LGR stands for low grain refrigerant. These are compressor-based dehumidifiers that add a second condenser coil. The extra coil reheats the air after it has been chilled and dehumidified, allowing the evaporator coil to stay colder and pull more moisture from the air, even when the room temperature is lower or the humidity is not extremely high.

This design is common in water damage restoration because it excels at removing moisture from building materials and in spaces that are both cool and damp. For a deeper explanation of the technology, see our guide to LGR dehumidifiers.

How a standard compressor dehumidifier works

A standard compressor dehumidifier uses a single refrigeration cycle. A fan draws humid air over a cold evaporator coil, which condenses water vapor into liquid. The cooled, dry air then passes over a warm condenser coil and is returned to the room at slightly above room temperature.

These units are efficient and affordable for typical home use, but they lose capacity as the temperature drops. The U.S. Department of Energy notes that frost can form on the coils when air temperature falls below 65°F (about 18°C), reducing performance and causing the compressor to cycle on and off without removing moisture. Many standard units include an anti-frost sensor that shuts the unit off until it defrosts.

Because of this, standard compressor dehumidifiers are best for spaces that stay above 65°F, such as living rooms, bedrooms, or heated basements.

Key differences at a glance

The table below summarizes the main differences between standard compressor and LGR dehumidifiers. Remember that the right choice depends on your space's temperature and humidity levels.

Moisture removal efficiency: why LGR units shine

LGR dehumidifiers remove more water per kilowatt-hour in cool, damp conditions because the reheated air keeps the evaporator coil colder for longer. This makes them particularly effective at drying out wet materials after a flood or in a musty basement, where the goal is to lower the moisture content of wood, drywall, and concrete.

Controlling moisture is the first step in preventing mold growth. The Environmental Protection Agency (EPA) stresses that the key to mold control is moisture control, and that wet or damp areas should be dried within 24 to 48 hours to prevent mold from taking hold. An LGR unit is often the best tool for this job because it can pull water out of porous materials more aggressively than a standard unit.

If you’re dealing with a space that consistently feels damp and has a musty odor, the EPA’s guidance suggests using a dehumidifier to keep humidity low. For extreme conditions, an LGR unit will get you to a dry state faster.

When to choose an LGR dehumidifier

Choose an LGR unit if you are managing a basement that stays below 65°F, a crawl space with persistent moisture, or a space that has suffered water damage. These units excel in environments where a standard compressor would constantly cycle on and off due to frost or lose effectiveness as the humidity level drops.

Restoration professionals use LGR dehumidifiers because they can remove moisture from building materials even in low-humidity conditions. For a look at the best models available, see our best LGR dehumidifiers guide.

Also consider an LGR unit for a crawl space, especially if you are planning encapsulation. The best crawl space dehumidifiers often are LGR models because they handle the cooler, damp environment well. View our best crawl space dehumidifiers roundup for examples.

When a standard compressor unit is enough

For most living spaces, a standard compressor dehumidifier is perfectly adequate. If the room is heated and stays above 65°F, a standard unit will maintain a comfortable humidity level without the extra cost and complexity of an LGR design.

Bedrooms, living rooms, offices, and finished basements that are kept warm can all benefit from a conventional compressor dehumidifier. These units are also quieter and use less energy in normal operating conditions, which matters if you run the unit frequently.

If you’re shopping for a general-use dehumidifier, start with our best 50 to 99 pints dehumidifiers guide, which covers models ideal for living areas. You can also search by square footage with our best 1,501 to 3,000 sq ft dehumidifiers list.

Energy efficiency and integrated energy factor

Both standard and LGR dehumidifiers are rated by the Department of Energy’s Integrated Energy Factor (IEF), measured in liters of water removed per kilowatt-hour (L/kWh). A higher IEF means better efficiency. ENERGY STAR certified dehumidifiers use 20% less energy than conventional models to remove the same amount of moisture, thanks to more efficient coils, compressors, and fans.

LGR units tend to have lower IEF values than standard units in warm conditions because the extra condenser coil adds some energy load. However, in cool, damp basements, an LGR unit may achieve a higher effective efficiency because it continues to remove moisture while a standard unit would be off due to frost. The right choice depends on your operating environment.

If you want to maximize energy savings, look for an ENERGY STAR certified model. Our best Energy Star dehumidifiers guide highlights the most efficient options on the market.

Temperature, humidity, and capacity ratings

Dehumidifier capacity ratings changed in 2020 when the DOE updated its test procedure to measure performance at 65°F rather than 80°F. This change means newer ratings better reflect real-world basement conditions, but they also report lower pint capacities than older models with the same physical size.

When comparing an LGR to a standard unit, pay attention to the operating temperature range specified by the manufacturer. The ENERGY STAR guidance recommends considering a low-temperature dehumidifier if your space typically falls below 65°F. LGR units are specifically designed for such conditions.

Remember that a higher pint rating does not always mean better moisture removal in your specific situation. Think about the temperature and humidity levels of your space, then choose the technology that matches those conditions. For help sizing, see our sizing dehumidifier by sq ft article.

What to pick for your use

Questions

What does LGR stand for in dehumidifiers?

LGR stands for low grain refrigerant. It refers to a compressor dehumidifier design that uses a second condenser coil to reheat the air, allowing the unit to continue removing moisture effectively in cooler and lower-humidity conditions.

Is an LGR dehumidifier better than a standard one?

It depends on the environment. LGR units are better for basements, crawl spaces, and restoration work where temperatures are low and humidity needs to be pulled from materials. For normal living spaces above 65°F, a standard compressor unit is sufficient and often more efficient.

Can I use an LGR dehumidifier in my living room?

You can, but it may not be necessary. LGR units are designed for harsh conditions and may use slightly more energy in warm rooms. A standard compressor dehumidifier is usually a better fit for a living area.

Why do LGR units cost more than standard models?

LGR units have an additional condenser coil and often more robust construction for continuous operation in demanding environments. This added complexity typically raises the price compared to a standard model with the same pint capacity.

How do I know which type to choose?

Measure the temperature and humidity of the space. If it stays below 65°F and is damp, choose an LGR unit. If it is a typical heated room, a standard compressor unit will work well. Also consider whether you need to dry materials or just control humidity in the air.