[ Understand that I am not involved with the below mentioned company in any way. I just like the product. ]
Update: Just adding a quick note to update this page. It is Janurary 2007, 3+ years after I installed my Desert Spring unit and I continue to like the unit very much. I have also added to the system one of their autoflush units which opens a valve every 48 hours to refresh the water for those folks in hard-water areas. The end of my second season I was not flushing the unit by hand enough and I did get some hard-water buildup. From what I can see the autoflush does reduce this significantly. I think you can buy the unit with the autoflush as a package, which I recommend.
One of my big pet peeves is wasted water. I'm not consistent about this since I like long showers but I do have a 750 gallon sistern in my garage feeding my outside spickets. That's a subject for a future thoughts column however.
So because I hate wasting water, my old humidifier annoyed me to no end. If you don't have a humidifier in your home you should consider getting one -- especially if you have forced air heat. Humidity is very important for comfort, plants, furniture, health, etc.. Experts recommend humidity levels in your home of 30-50% through numerous studies. Humid air feels hotter and makes the home more comfortable, keeps wooden furniture and floors from drying out and getting brittle, lowers bacteria levels, etc..
Basically there are a few different types of humidifiers which are designed to go onto the side of a forced air furnace:
The product that I found and installed over the winter of 2003 is called the Desert Spring Humidifier. It does not waste water and suffers significantly less from the hard water limitations of the other systems described above. It has a reservoir of water but instead of absorptive pads, it utilizes plastic disks (see image at right) in an accordion shape which are rotated through the water. The water coats the disks and evaporates into the air passing around the 15 square feet of surface area provided by the disks. The mineral deposits from hard water wash off the disks and collect in the reservoir to be drained off. The unit comes with a screw knob at the bottom of the reservoir which I attached a garden hose ball valve so you can drain the unit easily into a bucket every month or so.
The humidifier is connected between the hot output and cool input to your furnace. Some of the hot air output is redirected through the plastic disks coated with water and into the input side of the furnace. There is a float value inside of the unit which maintains the water at a prescribed level. It comes with a standard water pipe piercers like you'd have on your freezer's ice maker which tap into a cold water pipe. They provided plastic tubing but I replaced it with 1/4" copper tubing which is stronger. I connected the included 24v DC transformer to the output from my furnace blower motor circuit so that it only rotates when air is passing through the unit. I did not install the humidity sensor which comes with the unit on my furnace because we've always needed more humidity.
So far I am impressed with the unit. It seems very well made, comes with decent installation documentation and a video which I'd recommend watching. I watched it after I installed it (of course) and it answered some questions and would have saved me time. It uses minimal electricity and water and we immediately saw the droplets of water in the corners of the window panes that we were supposed to get. No recurring charges or pads to change. The only maintenance is the draining of the reservoir every month or so (or use their autoflush device which I recommend). It would also be good to wipe out the reservoir and rinse off the plastic disks at the start of the season. I also turn off the water in the Spring and turn it on in the Fall to be safe.
So if you are in the market for a humidifier I strongly recommend the Desert Spring Humidifier. It is currently selling for close to US$200-300 from online vendors which is more than other models but worth the difference. This difference will have paid for itself after a couple of years of water and pad costs (often US$10-$20+ and need to be changed monthly).
The following are a number of notes that I took that augment the installation manual that comes with the unit. Unless you are pretty handy I'd recommend getting someone to install it for you. The included parts (see image at right) are many. I'm a pretty handy guy and I'd rate this a 3 out of 5 on my difficulty scale. Took a while but not too difficult.
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