I was asked about which kind of humidity generating gadget is better for a BH.
First let me write about these three types that are commonly used.
1) Chicken Coop Humidifier.
This seems to be the most commonly used. Nearly all used this type but it is not necessarily is the best.
The machine use a rotary motor that will turn a blower plate. It used to have the fan on the top but now moved to the bottom.
Its lifespan is about 3-4 years.
Main problem will be the ball bearing that mount the motor. Once the motor reached its lifespan it will start a kind of sound that generally not attractive to those birds.
It also pushes those fine water droplets to the top part of the gadget. If your ceiling is too low these mists tends to reach your nesting planks.
The only way out is to place a cover to divert the mist to its sides.
2) Ultrasonic Mist Maker.
Ultrasonic mist maker seems to be very popular in recent years.
Much more expensive as compared to chicken coop humidifier.
The method of operation have something to do with this plate that will vibrate at ultrasonic speed and convert water in liquid form into gas form.
Once water turned gas/mist it will flood above the water surface and all you need is a blower to push the mist out of the container.
The mist maker life is largely dependent on how long those vibrating plates last.
When the vibrating plate shakes it tends to generate heat and during the conversion there will be lots of scale deposited onto the "eyes".
The moment these so called scale covered the eyes surface there will be no mist from your machine.
The only was to go is to replace the eyes.
If your water supply is not filtered or cleaned the scale will form much faster.
I have seen so many units laid idle in BHs with this kind of problem.
I also have many experiences with this kind of gadget but stop using them.
3) The mist pump using hose and brass nozzles.
This might be the best among the three types.
The system consist of a water filter, water pump, high pressure hose and those brass nozzles.
Once you switch on the water from your tap will be sucked into the pump after a filter casing.
The pump will provide the necessary pressure head and push towards the hose connected to it.
The nozzle will allows those high pressured water out of the pipe and form a kind of mist.
You can install more nozzles if your pump is well chosen.
This is where the pump with nozzle is more efficient.
The pump can be mounted on the wall and those hose and nozzles at the walls too.
You will have no gadget on the floor.
My best recommendation is to deploy mist pump with at least 10-15 nozzles per floor.
Each nozzle is similar to a humidifier.
My recommendation is to fix those nozzle to face about 5 degrees towards the BH floor.
The wet markings on the floor will help to maintain the floor wetness.
You can either use a Hager timer or a Hygrostat to operate the pump.
Your main objective to have your BH floor wet so that it will make your BH humidity high, cool the BH a bit and at the same time reduce those dusts in the air.
The lesser those dusts are the whiter your nests will be.
Try to have two water filter types. One to remove those debris while the second is to remove those chlorine. You will be surprised when you see your nests transforming its colors.
Just try this idea and I am sure you will realized what you have been missing all these years.