How to Choose the Right Dehumidifier (LGR vs. Conventional Explained)

Walk into any home improvement store and you will find consumer dehumidifiers rated at 50 or 70 pints per day. Buy one for water damage restoration and you will likely be disappointed. Here is why — and what to use instead.

Why Consumer Dehumidifier Ratings Are Misleading

The PPD (pints per day) rating on a consumer dehumidifier is measured at 80°F and 60% relative humidity — ideal conditions for that type of unit. Real water damage situations rarely match these conditions. Rooms being dried are often cooler and, as drying progresses, become less humid — two conditions that dramatically reduce a conventional dehumidifier's output.

Conventional Dehumidifiers

These use standard refrigerant coils that condense moisture from the air. They work well for general humidity control in warm, humid spaces. However, their efficiency drops sharply as temperature decreases or as relative humidity drops below 40-50%. Once a room reaches 40% RH (still too wet for structural materials), a conventional unit struggles to extract more moisture.

LGR (Low Grain Refrigerant) Dehumidifiers

LGR units use a two-stage cooling process that pre-cools incoming air before the refrigerant coils. This allows them to continue extracting moisture at low temperatures (down to 35°F) and at low relative humidity (down to 20-30% RH). This matters enormously for structural drying — you need the dehumidifier to keep pulling moisture even as the room gets drier.

The Simple Rule

• General humidity control and prevention: A 50-70 PPD consumer unit is adequate
• Active water damage drying: You need a commercial LGR dehumidifier — period
• Not sure? Rent an LGR from Jar2. The cost difference is minimal and the drying speed difference is dramatic — often 2-3x faster

All Jar2 rental bundles include commercial LGR dehumidifiers matched to your job size. This is one area where the right equipment makes the difference between drying in 3 days or 10 days — and every extra day of wet materials increases your mold risk.