My family has several table-top humidifiers (the cool-mist/nebulizer kind) in the house that we use a lot during the winter. Distilled water is recommended for using in humidifiers because the dissolved solids and other stuff in tap water can cause a residue to accumulate on walls and furniture, and also in the humidifier.

Unfortunately none of my options seem to be very efficient ongoing strategies for obtaining water for the humidifiers. Here are the downsides of them:

Purchasing distilled water from the store

  • $0.78 per gallon
  • need to recycle all the plastic jugs
  • need to haul them all home from the store

Using water from my reverse osmosis system

  • RO systems use 5+ gallons for every 1 gallon of filtered water they produce
  • RO filters need replacing more often

Using a large water reservoir with an activated-carbon water filter (haven’t tried it myself yet)

  • this would have the benefit of using tap water without wasting a bunch of it (like the RO system does), but I read that there’s a lot of stuff in water that doesn’t get removed by activated carbon.

Is there a better way than these methods? I use about 1 gallon of water per day in the humidifiers.

  • Why not just buy an actual water distiller?
    – paparazzo
    Commented Dec 16, 2018 at 13:09
  • Not a bad thought... although those boil water with an electric heating element which would use quite a bit of electricity, so I'm not sure that would be a good ongoing solution for a gallon of water per day. Commented Dec 17, 2018 at 15:03
  • After reading a little about the electric distiller, the electricity required isn't too bad compared to buying gallons of distilled water at the store. The main downside to using a distiller would be having an appliance to clean and maintain, and having the upfront cost of $100+ Commented Dec 17, 2018 at 15:13

2 Answers 2


I suggest that you take a fully sustainable path by doing away with machine humidifiers and switching to using natural humidifiers.

Houseplants such as areca palm, rubber plant, peace lily, English ivy and spider plant have been heavily researched by NASA and shown to significantly increase humidity in the air through a process called transpiration. Also, these same plants can decrease airborne pollutants by up to 87% in 24 hours.

You'll have clean, oxygenated, humidified air requiring no use of electricity or manufacture of plastics, and you'll also increase the beauty of your home.

Here are links to a couple articles:

hunker - plants that add moisture to the air

sfgate - indoor plants can battle pollution / NASA research shows they absorb chemicals

And no need for distilled water.


Use a RO system which uses a brackish water membrane (TDS limit upto ~5000) so you can reuse the reject water again as feed water. This of course depends on the water quality in your area. It might be a little more expensive and larger initially but is a good investment in the long term considering you'll be using it regularly.

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