The easiest system to run, consisting of a water tank, wick and fan. The wick absorbs water and the fan blows air onto the wick, the water evaporates and the humid air is blown out into the room, raising the humidity.

About the same idea as the evaporation model above, but with a spinning disc or propeller that is breaking the water droplets into tiny droplets which creates a fine mist. You can actually see the mist when it comes out of the machine and it usually runs a little quieter than the evaporation models.

This system use ultrasonic sound waves to vibrate the water converting it into a cold fog that you can see.

At first I chose an inexpensive cold air impeller driven humidifier, but thankfully that one broke down after about 9 months. I say thankfully because it was not very effective and it was very loud to run- Luckily I got to replace in under warranty. I replaced it with a 5L capacity ultrasonic cold air humidifier instead (Honeywell HH200E4). That one lasted about 6 months, and I have run through three of those now (luckily under warranty)… they just do not last. Last time they replaced it with a “Wilfa HU-6″ ultrasonic humidifier (still under warranty). We’ll see how long that one lasts…

Since the cool fog kind of blows out of the nozzle then immediately fall I needed a rig to bring the flow further up in my growing window then have it gently fall down on the 3 levels of orchids below so I get better coverage and at the same time raising the over all RH in the room. But I do not wish to keep the 5L water container for the humidifier 3 meters up in the air, so I built a chimney using regular PVC pipes and a cheap funnel. Three holes drilled in the pipe running across the top and the fog flows down the top like magic..! Read about the installation here.

In my small growing room, with the door closed, I get about 70% humidity at night. I keep it on a timer running the unit every other half hour for a half hour at a time every night – and once again at noon for good measure.

In the intermediate vivariums I used to have 3 humidity trays on the bottom filled with water to help raise the humidity. But after filling the space with orchids I do not have to keep the humidity trays anymore, they serve as collection trays instead. Thanks to the amount of plants and the humid growing media, humidity stays fairly constant. But I run a small ultrasonic humidifier for about 15 minutes twice a day to help maintain a good level. I use the same humidifier for both of the intermediate vivariums, splitting the fog in two with the help of a rubber hose and some duct tape. Simple but effective. A temperature and hygrometer tells me all is working like it should. I spent about $15 on one that is showing both humidity and temperature, plus save the high/low value so that you can keep track of the measurements.

PS! See all those hard water stains I used to get on the vivarium glass? A pain in the, well, you know what. This was fixed when I finally got a reverse osmosis filter. The filtered water does stain the glass in this way. A very nice added benefit.

In the cool vivarium I use a “Wilfa HU-6″ ultrasonic humidifier with an option for either hot or cold steam (I will run it cold of course) with a capacity of up to 300 ml/hour and the water tank holds 6 liters. I use PVC pipes to make another “chimney” for the fog so I kan keep the unit on the outsde. I pipe it into the viv. through a hole in the side. I control the RH with a Lucky Reptile Humidity Control II humidistat, the same brand and concept as my thermostat, with two circuits making it possible to have different settings for day and night. I set mine for 75% during the day and 85% at night with a 5% differential, which means that the humidifier will start up as soon as the measured humidity drops 5% below the desired setting. A temperature and hygrometer tells me all is working like it should.