a red dehumidifier on a wood floor with mold on the walls behind it and a caution sign for hazardous material potential

Freon (R-22) is a hazardous gas that limits oxygen supply to the lungs and cells in the body. However, it’s among the most effective refrigerants in cooling and condensing vapor and has been used by the HVAC industry in air conditioners and dehumidifiers.

This gas

contributes to the depletion of the Ozone layer and has been banned in the US as of January 1, 2020. 

In 2010, the HVAC industry started making the switch from R-22 to 410A gas. This is a more environmentally-friendly option but still should not be vented into the atmosphere. Nor is it meant to be handled by anyone other than HVAC professionals.

If your dehumidifier was manufactured after 2010, it likely does not use Freon (R-22) as its coolant. However, that doesn’t mean it is safe to work on these units yourself.

Why Freon (R-22) Was Banned in the U.S.

Refrigerant gas lines used to charge large dehumidifiers. There is a green bottle and four lines with two gauges.
Some dehumidifiers use refrigerants to take water out of the air via condensation. Large, whole-house units sometimes need regassing, which must be done by a qualified professional.

Before the U.S. Environmental Protection Agency (EPA) ban in 2020, compressor-based dehumidifiers used Freon to convert the collected vapor into liquid.

The Freon was then passed through a set of coils to release heat outside the dehumidifier.

While Freon is an extremely effective refrigerant, it’s also a hazardous gas. It contains chlorofluorocarbons (CFCs) and is not eco-friendly in the slightest.

It’s worth mentioning that Freon is only risky if it leaks from the dehumidifier’s condenser coils. Unless the system is leaking, it poses no danger to you.

It is worth noting that a dehumidifier with a small, micro leak will likely not have any adverse effects to your health. 

The odds of a catastrophic leak are extremely low. Some outside source would have to damage the unit for that to occur. But just to be safe, if you hear hissing or see gas being expelled from the unit, get everyone outside immediately!

Wait for the system to vent completely and then go back inside, open all windows and doors and wait for the gas to clear. This is not ideal, as the Freon has escaped into the atmosphere, but there is nothing you can do about it at that point besides to get yourself safely away so you don’t breathe it in.

The main risks of Freon include:

  • Cardio-toxicity. According to the National Library of Medicine, Freon is heavier than air. Thus, it lodges in the lungs’ alveoli impairing oxygen uptake. The gas can also increase heart rate and blood pressure, possibly leading to cardiac arrest.
  • Organ damage. If inhaled for a long period, Freon can damage the liver, kidneys, and other organs.
  • Ozone layer depletion. The Ozone layer shields the earth from the sun’s harmful ultraviolet (UV) rays. However, CFCs in Freon and other gasses contribute to the depletion of this layer, exposing the earth to UV rays.
  • Cancer. The gas contributes to the depletion of the Ozone layer, exposing human skin to UV rays which cause skin cancer. According to the National Library of Medicine, exposure to UV rays leads to squamous cell carcinoma (SCC) and basal cell carcinoma (BCC).
  • Nervous system damage. Freon damages the central nervous system and can cause paralysis with prolonged exposure.

Other Hazardous Liquids in Dehumidifiers

A closeup of a condenser coil on a home dehumidifier.
The inner workings of a dehumidifier are a mystery to most people. Some components use hazardous liquids to do their job.

Besides coolant, some dehumidifiers use liquids such as ethylene glycol and propylene glycol to enhance efficiency.

These two substances are environmentally friendly and don’t damage the Ozone layer. However, they’re poisonous if ingested and can cause skin irritation.

While these liquids are not as dangerous as refrigerants, you should still take precautions not to touch or ingest them. In case of skin contact, wash the area with plenty of soap and water.

It is a good idea to keep these units away from children and pets.

Types of Dehumidifiers

A collage of three different home dehumidifiers.
Dehumidifiers fall into two broad categories: refrigerant dehumidifiers and desiccant dehumidifiers.

There are two main types of dehumidifiers based on their dehumidification process:

  • Refrigerant dehumidifiers
  • Desiccant dehumidifiers

Refrigerant Dehumidifiers

Refrigerant dehumidifiers use refrigerants to cool and condense the water vapor, much like an air conditioner. Refrigerant dehumidifiers built after 2010 use 410A as coolant.

While this gas is more environmentally friendly than its predecessor, R-22, it is still unsafe to breathe in should the system have a catastrophic leak. Fortunately such events are extremely rare.

Refrigerant dehumidifiers are most effective at room temperature and not in cooler temperatures. When used in places with temperatures below 18°C (64.4°F), ice forms on the metal cooling plates, preventing the dehumidifier from working properly.

Highly modified refrigerant dehumidifiers can work under low temperatures using advanced features. However, these units are more expensive.

Desiccant Dehumidifiers

These types of dehumidifiers use a desiccant (a hygroscopic substance) to absorb water vapor from the air. The most common desiccants used are silica gel and calcium chloride.

The advantage of these dehumidifiers is that they can work at low temperatures without the risk of ice formation. This makes them ideal for use in basements and garages.

Desiccant dehumidifiers are quieter and have a longer lifespan than refrigerant dehumidifiers. However, they are more expensive than their refrigerant counterparts.

The Workings of Dehumidifiers

A light gray dehumidifier standing on a gray floor with a gray wall behind it.
Dehumidifiers made since 2010 should not contain Freon.

Dehumidifiers work to maintain relative indoor humidity. The indoor relative humidity should be between 30 and 60 percent.

Excessive humidity in your home can lead to the following:

  • Mold and mildew growth.
  • Peeling paint.
  • Bacterial and viral infections.
  • Increased dust mite activity.
  • Uncomfortable conditions.

Parts of a Dehumidifier

The following are the main parts of a refrigerant dehumidifier:

  • Compressor. The compressor is a pump that pressurizes the refrigerant.
  • Condenser coils. The condenser coils release heat outside and are usually located at the back of the dehumidifier.
  • Expansion valve. The expansion valve’s job is to regulate the flow of refrigerant to the evaporator coils.
  • Evaporator coils. These are located inside the dehumidifier. They absorb heat from the air, thus cooling it and causing water vapor from the air to condense onto them.
  • Fan. The fan helps circulate the air over the evaporator coils.

The working principle of all dehumidifiers is based on the simple fact that water vapor condenses when in contact with a cold surface.

In a refrigerant dehumidifier, the compressor pressurizes the refrigerant and forces it into the condenser coils. The coils release the heat to the outside air, making the refrigerant cool and liquefy.

The expansion valve regulates how much of the liquid refrigerant flows into the evaporator coils for cooling and condensation purposes. The fan helps to circulate air over the evaporator coils.

The now condensed water drips off the evaporator coils into the storage tank, and the refrigerant moves on to the compressor, where the cycle starts again.

In a desiccant dehumidifier, the air passes over the cooling coils to be cooled before it reaches the desiccant. The desiccant is designed like a wheel that turns slowly through the incoming air.

The humid air is passed over the turning desiccant, which absorbs the water vapor. Subsequently, the dry air is then reheated and released into the room.

Finally, warm air is passed over the water-saturated desiccant to reactivate it by driving off the moisture. The condensed water drops into the dehumidifier tank for disposal.

A row of three different-colored tanks of eco-friendly refrigerants

Most use 410, which has already been covered, plus none of these refrigerants are truly eco-friendly, it’s just that they are a little less bad than R-22.

Final Thoughts

While your old dehumidifier may use R-22, it should pose no danger to you. Unfortunately, this means if it has a leak or needs service, you will be unable to add refrigerant to it and will likely need to upgrade to a newer model. 

All in all, you should not be worried about any hazardous material leaking from your dehumidifier. That is not to say that it is safe to work on these systems yourself.

If you try to open up the system, you might cause a leak. While the newer refrigerants aren’t as bad for the environment as R-22, they still aren’t safe to breathe in. It’s best to leave it to the professionals.

For more information about refrigerants, please read our article, “The 11 Best & Most Affordable Eco-Friendly Refrigerants“.

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