LGR Dehumidifier
A low grain refrigerant dehumidifier, the workhorse drying machine that can keep pulling water out of air that is already fairly dry.
The short version
- Low grain refrigerant machines pre-cool incoming air so they keep condensing water at low humidity levels where a standard unit stops being effective.
- They are rated by pints of water removed per day, and the rating is what a scope uses to size the equipment count.
- They discharge warm, dry air back into the space, which is why a drying chamber feels hot.
- Desiccant dehumidifiers are the alternative for very low humidity targets and for dense materials such as hardwood, plaster, and concrete.
- Equipment is billed per unit per day on insurance estimates, so the count and the days need moisture readings behind them.
What it actually means
A refrigerant dehumidifier works like an air conditioner that keeps the heat: it pulls room air across a cold coil, water condenses out, and the air is reheated and returned to the room. A conventional unit loses effectiveness as the air dries, because there is less moisture available to condense. A low grain refrigerant unit adds a pre-cooling stage so the air reaching the cold coil is already closer to its dew point, which lets the machine keep extracting water at grain levels where a standard dehumidifier stalls.
That matters because the last part of drying is the hard part. Getting a room from very wet to moderately dry is easy. Getting the remaining bound water out of framing and subfloor requires holding the room air genuinely dry for days, and that is exactly the condition low grain refrigerant machines are built for.
Desiccant dehumidifiers take a different route, passing air over a moisture-absorbing wheel rather than a cold coil, which lets them reach lower humidity than refrigerant machines. They are the tool for specialty drying: hardwood floors, plaster, masonry, and large commercial spaces.
What it looks like on a real job
Sizing is not guesswork. A restorer calculates the volume of the affected space, factors in the class of the loss and the materials involved, and places enough dehumidification capacity to hold the chamber dry while the air movers keep surfaces evaporating. Then the intake and discharge readings on each machine confirm the sizing was right.
On the claim side, each machine is a line item per day. That is the honest reason drying invoices grow with time: the equipment is metered. It is also why daily monitoring visits exist. Removing a machine as soon as its area reaches the dry standard keeps the invoice defensible, and leaving equipment in place with no readings to justify it is the fastest way to have days denied.
Questions we get asked
- Why is there so much equipment in my house?
- The count comes from the size of the wet area and the type of materials involved, not from preference. Air movers create evaporation at the surfaces and dehumidifiers remove that moisture from the air; too few of either and the drying stalls, which costs more days than the extra machines would have.
- Can I turn the equipment off at night?
- Please do not. Drying is cumulative and interrupting it lets moisture redistribute back into materials that had started to release it, which adds days. If noise or heat is genuinely unmanageable, call your technician and let them rebalance the placement instead.
- How long will the equipment stay?
- Until documented readings show the affected materials have reached the dry standard, commonly around three days on a straightforward loss and longer where hardwood, plaster, or concrete is involved. The moisture log, not the calendar, decides.
- Will running all that equipment spike my power bill?
- It uses real electricity, and on covered losses the added utility cost is often something your insurer will consider as part of the mitigation. Keep the bills from the drying period so the comparison to a normal month is available.
Official sources
Everything on this page rests on the documents below. Read them yourself, they are all free.
Last reviewed against these sources on August 26, 2026. These definitions are general information about restoration work and property claims in Florida, not legal advice or a coverage opinion. Your policy language and the facts of your loss control what is owed. Swift Response Restoration Inc is a licensed restoration contractor, not an insurer, a public adjuster, or a law firm.
Not sure how this affects your loss?
Send us the estimate, the photos, or just tell us what happened. We will walk you through what you are looking at and what the next step is. Free inspection, no obligation, and someone answers the phone at any hour.
Related terms
Psychrometry
The science of air and water vapor, temperature, humidity, and vapor pressure, that structural drying is built on.
Grains Per Pound
An absolute measure of how much water vapor is in the air, used to prove a dehumidifier is actually removing moisture.
Air Mover
The high-velocity fan that drives evaporation by stripping the saturated layer of air off wet surfaces.
Dry Standard
The documented moisture level a material has to reach for the drying to be finished, taken from unaffected material in the same building.