LGR Dehumidifier: Best Picks for Flood & Water Damage

LGR stands for low grain refrigerant. "Grains" are a measure of how much water vapor is in a pound of air (grains per pound, or GPP). A standard dehumidifier works well in very humid air but slows down as the air gets drier. An LGR unit pre-cools the incoming air so its coil can keep condensing water at lower humidity levels, which is exactly what you need in the last stage of drying a flooded room: pulling moisture out of walls, subfloors and framing.

Restoration pros track GPP rather than relative humidity because GPP does not change with temperature. Several LGR units show it on the display.

Sources: maker spec sheets and Amazon listings for each model.

LGR dehumidifiers compared

Dri-Eaz Revolution and DrizAir 1200

Two other Dri-Eaz names come up often. The DrizAir 1200 is an older conventional (not LGR) unit rated at 64 pints at AHAM and 145 at saturation; Dri-Eaz lists it as replaced by the DrizAir 1400. The Dri-Eaz Revolution is a smaller LGR unit; we could not find a clean spec sheet for it, so check the current figures with a Dri-Eaz dealer before buying.

LGR vs refrigerant

Both LGR and conventional units are refrigerant dehumidifiers; LGR is a design that adds pre-cooling so it keeps working as the air dries. In the first day after a flood, when the air is saturated, a conventional unit and an LGR unit both remove a lot of water. The difference shows on days two to five, when the air is drier and the job is pulling the last moisture out of building materials. That is where LGR units earn their price.

Renting vs buying

For a one-off flood, renting is often the better deal. Many tool-rental and restoration-supply companies rent LGR dehumidifiers and air movers by the day or week. Buy if you have recurring water problems, a large basement that floods seasonally, or if you are a contractor. If an insurance claim is involved, a professional restoration company will usually bring its own equipment and document the drying with GPP readings.