Last Updated on October 23, 2026 by Umar Farooq
The dehumidifier refrigerant in a compressor machine is one of three: older units mostly R410A, newer ones R32 or R290 (propane), and the name is printed on the rating plate. Desiccant machines use none at all. The change from one to the next is driven by regulation, not by anything you will notice in the tank.
I have read a lot of manuals now, and the R290 paragraph is the one that makes people sit up, because the word “flammable” appears in the first line. It deserves a calm read rather than a panic or a shrug, so here is what the sources actually say.
Which dehumidifier refrigerant is in your machine: R410A, R32 or R290?
The refrigerant is the fluid sealed inside the compressor, evaporator and condenser loop. It boils in the cold coil, which is what chills the air below its dew point, then gets squeezed hot by the compressor and cools back to liquid. How a dehumidifier works walks through that loop step by step. This article is about what is in it.
| Refrigerant | What it is | GWP (100-year) | Flammability class |
|---|---|---|---|
| R410A | HFC blend, 50% R32 and 50% R125 | 2,088 | Not flammable |
| R32 | Single HFC | 675 | A2L (lower flammability) |
| R290 | Propane, a hydrocarbon | 3 | A3 (higher flammability) |
The GWP figures are from EPA’s own GWP reference table, which marks the R410A value as calculated from its blend. R290’s 3 matches the figure printed in the Dry Nature 17/21 manual, and the A2L and A3 classes are from an EPA webinar on flammable refrigerants, which shows propane in the higher-flammability A3 group and R-32 among the A2L refrigerants. R410A being non-flammable is general industry knowledge, which is the reason it was the default for so long.
I could not find a published survey of what share of models on sale use each one. Anyone quoting you a percentage has invented it. The only reliable answer for your own unit is the rating plate, or the refrigerant line in the manual.
Why manufacturers are moving off R410A
Because the law now caps how warming a refrigerant can be. In the US, EPA’s Technology Transitions rules under the AIM Act set a GWP limit of 700 for residential dehumidifiers, with a manufacture and import date of 1 January 2025. EPA’s HFC restrictions by sector page lists the row, and its footnote says sale, distribution and export are prohibited three years after that date. On that footnote’s arithmetic, the cut-off for selling old R410A stock is 1 January 2028. (That date is my sum, not a line on the page.)
Look at the chart and the choice is obvious. R410A at 2,088 is nearly three times the limit. R32 at 675 squeaks under it. R290 at 3 is nowhere near it. EPA issued a reconsideration rule in May 2026 that changed deadlines for several other sectors, but at the time of writing the dehumidifier row on that page is unchanged.
Two things follow. First, the machine you buy in a few years is very likely to be R32 or R290, and the R410A units are the ones heading for the second-hand market. Second, if you are weighing a used dehumidifier, the refrigerant on the plate tells you roughly how old it is, which is a more honest clue than the seller’s “barely used”.
What R290 propane means in your living room
R290 is propane, the same family of gas as camping cylinders, in a very small sealed charge. The Dry Nature 17/21 manual puts the charge in the CO2-equivalent line: it prints 0.075 kg for the 17 model, which is 75 grams. Its manufacturer also argues the gas is efficient enough that “the units therefore need less filling”. That is a manufacturer’s claim, not a lab result, so treat it as one.
The manual does not hide the downside. It says the refrigerant “is flammable and inodorous” and that it “can be ignited only by fire”. Odourless is the bit worth remembering: you will not smell a leak.
What the manual tells owners to do. Quoting the Dry Nature 17/21 manual, an R290 unit “has to be installed, used and stored in a room with a floor area larger than 4 m2”. It must be stored in a room “that doesn’t have any continuously operating ignition sources (for example: open flames, an operating gas appliance or an operating electric heater)”. It says “Do not pierce or burn”, do not try to speed up defrosting or clean the unit other than as the manufacturer recommends, and that repairs “carried out by unqualified personnel may be dangerous”. For repairs, contact the authorised service centre. Your own manual is the rule for your own model.
So the practical homeowner version is short. Put it in a room bigger than 4 m² (about 43 sq ft, which is a small box room), keep it away from a gas hob or a running heater, do not stab the coil with a screwdriver to dislodge ice, and leave anything inside the sealed circuit to someone certified. I will not tell you how to chase a leak or top up gas, because that is certified work with licensing behind it, and a dehumidifier circuit is a sealed unit rather than a refillable one.
Does R32 need the same caution?
Yes, the same manual-first habit, with a lower flammability class. The EPA webinar groups R-32 with the A2L refrigerants, which burn less readily than propane’s A3, and the manuals I opened that cover both gases carry one combined warning. A Heinner HDU-M10 manual I read has a heading, “Warning for using R32/R290 refrigerant”, with the same instructions: no ignition sources, do not pierce or burn, and anyone working on the refrigerant circuit should hold a valid certificate. Read your own manual to see which paragraph applies to your model.
What the refrigerant does not change
This is where I would spend your attention, because the refrigerant is quietly the least interesting thing on the spec sheet for most buyers.
- How it dries. The cold coil works the same way whatever is in the loop, so your pint rating is still the number to compare, and it still comes from a test at fixed conditions rather than from the gas.
- Where to put it. Central, clear of walls, doors open, same as ever. R290 adds a minimum room size and an ignition-source rule on top.
- Whether it is a repair job. A compressor that hums but never starts, or a coil that ices in a warm room, is a mechanical or sealed-system problem on any refrigerant. The fan-runs-but-compressor-doesn’t guide covers what you can safely check yourself. Anything involving opening the circuit is for a certified technician.
- Whether you need one at all. A desiccant dehumidifier uses no refrigerant, but it costs more to run in a warm room, so refrigerant anxiety is a poor reason to switch.
My view, and I will stand on it: do not choose a dehumidifier because of its refrigerant. Choose for capacity at your room’s temperature, noise and drainage. The refrigerant decides the paragraph in the manual you must follow, not how well the machine dries.
Check the rating plate once, then follow that paragraph
Find the dehumidifier refrigerant on the rating plate (usually the back or base), note whether the manual carries a flammable-gas warning, and follow it. That is the entire job. If you have an R410A machine that works, nothing about the new rules forces you to scrap it. If you are buying new, expect R32 or R290 and plan the room and the heater accordingly.
FAQ
What refrigerant do dehumidifiers use?
Compressor models use a sealed refrigerant: older ones mostly R410A, newer ones R32 or R290 propane. The rating plate and manual name it. Desiccant dehumidifiers use no refrigerant at all.
Is R290 dangerous in a dehumidifier?
R290 is flammable and has no smell, which is why manuals give rules on room size, ignition sources and not piercing the unit. In normal use, following the manual is the safeguard, and any repair involving the sealed circuit belongs to a certified technician.
Why are dehumidifiers switching to R290?
The main driver is the climate rules. R290 has a GWP of 3, against 2,088 for R410A, and EPA now caps residential dehumidifiers at a GWP of 700. R32 and R290 are the two common ways under that line.
Do dehumidifiers still use Freon?
Not the original freons. Those ozone-depleting types were phased out long ago, and the brand name is now loosely used for any refrigerant. Current machines use HFCs like R410A and R32, or propane.
Can I refill the refrigerant in my dehumidifier?
No, not as a home job. The circuit is sealed, and recharging or repairing it needs certified handling, particularly with flammable R290. If your machine is icing up or has stopped cooling, check airflow and room temperature first, then call a qualified technician or consider replacement.
Does a dehumidifier lose refrigerant over time?
It should not, because the loop is sealed. A slow leak is a fault, not wear, and the signs are a machine that runs but collects very little water. Do not try to locate or fix it yourself.
