When your water problems aren't limited to small wet spots or musty smells (e.g., your basement has flooded), an everyday dehumidifier just won't do the job. What you need is a heavy-duty machine with a lot more water-sucking power.
Commercial Grade Refrigerant (CGR)
These dehumidifiers were designed to be moved in and out of vehicles and go from one job to the next. There are a few reasons they are a good choice. For starters, the coils and compressors are much larger than in residential dehumidifiers. Designed for moisture-heavy areas, they offer professional results with somewhat more affordable pricing. The average cost is around $1,000, although most people who are dehumidifying due to serious water damage will want to rent a dehumidifier. Wheels and handles are a necessity on these, as their 80-or-more pounds make it hard to move them around. Many operate in low temperatures, down to 33 F, as well as in high temperatures, up to around 100 F. These dehumidifiers can take approximately 50 to 150 pints of water out of the air each day.
CGR is the most common dehumidifier and performs best in high-humidity situations. A cooled evaporator coil collects condensation, which drips into a tray before being stored in a bucket or pumped away. As the air becomes dry, CGR dehumidifiers need colder coils to operate and eventually stop removing moisture altogether.
Low Grain Refrigerant (LGR)
These dehumidifiers are the newest mechanical dehumidifiers available. Incoming air is pre-cooled, so the coil doesn't have to be as cold and more condensation can form on it. This lets them avoid some of the need for defrosting. The rest of the process is the same as with CGR. LGR dehumidifiers provide the best moisture removal for refrigerant dehumidifiers and produce dryer, warmer air. Wheels and handles are also a must on these machines, as they can weigh over 200 pounds. LGR dehumidifiers remove between 100 and 300 pints of water per day. They can withstand temperatures as low as 33 F and as high as over 100 F. LGRs can produce quicker results, avoid mold growth and likely cost less in a rental situation due to decreased time needed.
When neither CGR nor LGR dehumidifiers will do, desiccants and air exchangers can provide further dehumidification or more efficient results. Many experts recommend combining your efforts, using a refrigerant in the beginning and finishing with a desiccant.