Recharging Desiccants for Hearing Aid Dehumidifiers

With the hot summer months in full swing, hearing instrument wearers rely on dehumidifiers to remove damaging moisture that inherently builds up within hearing aids.  Prior to retiring for the night, hearing aids should be cleaned, disinfected and then placed in a dehumidifier, on top of the desiccant, with the hearing aid battery doors in the open position.  The hearing aids remain in the hearing aid dehumidifier overnight. Doing this every night will help prolong the life of the hearing aid and minimize moisture damage.

A wide variety of dehumidifiers are commercially available with most incorporating the use of a desiccant. Desiccants are small beads that capture and stow moisture from hearing aids. The small beads are typically enclosed in some sort of casing, pillow or pouch although some dehumidifiers house desiccant beads loosely in a jar (without encasing them in a pillow or pouch) which is not ideal since the beads can easily spill out and potentially cause a tripping hazard.

Regardless of the packaging, the desiccant must be activated either once or reactivated from time to time. Depending on the specific product, some desiccants are activated by simply pulling off a foil cover.  Other desiccants must be activated and reactivated in the microwave (i.e. 30 seconds to 1 minute or so  on high) or in a conventional oven (300º – 350º F for 30 minutes). Since there are a variety of products available on the market, it is critical to follow manufacturer instructions.

Some or all of the desiccant beads may have been treated such that they change color depending on how much moisture the beads have absorbed over time.  For example, some desiccant beads have been treated with cobalt chloride, a chemical that turns beads cobalt blue in color when fully activated.  Over time, they lose their hue, eventually turning pink. When the indicator beads turn pink, it is time to recharge the desiccant.  Other products, such as Audiologist’s Choice, use cobalt-free beads which are equally effective but more environmentally friendly.  With cobalt-free desiccants, the beads are orange/yellow when fully activated and ready for use; over time, the orange/yellow beads will change to green, serving as an indicator that it is time to reactive the desiccant. For more information, check out the quick one minute video on Recharging a Desiccant via the Oaktree Products YouTube page.

About AU Bankaitis

A.U. Bankaitis, PhD is a clinical Audiologist with extensive clinical, research, and business experience within the hearing industry. Dr. Bankaitis created this blog to educate her colleagues on viable product solutions for their patients and/or clinical practice.
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4 Responses to Recharging Desiccants for Hearing Aid Dehumidifiers

  1. Ralph Cross says:

    Thank you, thank you, thank you for this enlightening article. It is precisely what I was looking for, and you answered my questions beautifully! Your work is truly appreciated.

  2. Rick says:

    Nice info doc AU

  3. Dan Schwartz says:

    Revised

    When using a hearing aid dehumidifier, it is important to .NOT. leave the batteries in the instruments: As it turns out, zinc/potassium hydroxide/oxygen (“zinc-air”) cells are optimized to work at 50% relative humidity; and by putting the cells in the dehumidifier it will cause the electrolyte to dry out, shortening the lifespan:

    See this image: http://www1.duracell.com/oem/primary/Zinc/Images/5104.gif [if the IMG SRC html tag does not appear]

    Source: Duracell Technical Bulletin

    Dan Schwartz,
    Editor, The Hearing Blog

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