My cat has fleas and I tried using anything short of a bug bomb to get them off the cat and out of the house. However, all previous attempts have failed. Now I stumble on this idea that you can kill fleas using a dehumidifier. Is this true or am I falling victim to the internet?

  • 1
    Good luck, but the first-line treatment is usually spot-ons that interrupt the flea’s lifecycle, ovicidal spray, very frequent and thorough vacuuming, and patience. There’s a dormant stage in the flea’s lifecycle that’s impervious to anything, that the vibrations from the vacuuming awakens and lets you get rid of it. It’s these dormant invincible eggs that cause the fleas to return, so you need to keep up any intervention you’re doing and vacuum for some time after your cat stops scratching.
    – millimoose
    Sep 28, 2017 at 21:45
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    Apparently 95% of the fleas in your house are non-adults, so an intervention that kills just the adult fleas isn’t enough. You want to attack on all fronts.
    – millimoose
    Sep 28, 2017 at 21:48

2 Answers 2


No, Dehumidifiers do not kill fleas.

The most effective way is to use a topical or oral chew flea product on all pets (excluding reptiles and birds) in the household for a minimum of 3 months. If you live in an apartment/condo building or a hot climate you should treat your pets 12 months of the year. Areas that get snow and stays cold in the winter months the treatment starts from March until December.

Some recommended products are:

  • Advantage Multi
  • Bravecto
  • Revolution (southern USA this product is no longer effective for fleas)

Extra tips:

  • Wash bedding.
  • Vacuum everything daily.
  • Flea comb pets to remove fleas and flea dirt (flea larva eat flea dirt).
  • Bathe your pet to help remove fleas.

Fun flea facts

  • A female can lay 40-50 eggs per day and 50% of these eggs will be female.
  • The female flea begins producing eggs within 24-36 hours after its first blood meal and continues to produce eggs for >100 days if she remains on the host.
  • Fleas carry tapeworm that can be transmitted to your cat once eaten.
  • Fleas can be vectors for infectious organisms, such as Yersinia pestis (aka Plague), Rickettsia spp., Bartonella spp., and hemoplasma (Mycoplasma) spp.

Note When bathing pets do not bathe while on topical flea treatment and wait 2 days before applying a topic flea treatment AFTER a pet has been bathed.


I have been fighting these for a month now. I used a dehumidifier for years and turned it off when I found fleas in it. Do NOT use a dehumidifier to get rid of fleas. They do not care and they will love the water it sucks out of the air. Persistence is the key. Do not give up. Do not give in! Do all the things others have said.

They can stay dormant for up to 8 months until they sense a meal (warm body), so vacuuming is crucial as the vibration from a beater bar gets them going.

  • One more thought, I think the fleas actually crawled through the exhaust tube from the dehumidifier into the dehumidifier... Try to think of everywhere they might hide. I had to remove all paper products, all carpets, paper bags, boxes, keep stuff off the ground, keep vacuuming daily... Good luck and never give up!
    – Dan B
    Jul 26, 2018 at 20:22
  • Since I posted I have learned that a humid environment is ideal for fleas. Running a dehumidifier is helpful as it makes the environment less conducive for the buggers... Just (as stated above) do not use an exhaust tube as the fleas might crawl in it and lay eggs and put a little dawn in the dehumidifier after you drain it as it will keep it clean and if any fleas do get in there they will drown!
    – Dan B
    Aug 30, 2018 at 14:13

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