large portion of the U.S. has experienced prolonged periods this winter (2014) with temperatures
substantially below long-term averages. That means heating systems have been running much more
often than usual, and if you have a forced hot air system, that means the indoor humidity level
has been much lower than normal. In northern areas like where I live, humidity can easily drop
to near zero. Because of that, triboelectric charging to high voltage potential occurs merely by walking
a few steps across a carpet, resulting in a sometimes painful discharge arc when a metal object
The only way to mitigate low humidity conditions is to add water back into
the air. One way is to use a free-standing humidifier that either evaporates water back into
the air or to use an ultrasonic humidifier that blows a fine water mist into the air, which
then evaporates. Ultrasonic types tend to put more water back into the air, but if you have
a high chemical content in your water - such as lime or calcium - you will soon find a layer
of dust deposited on everything in your house. It lays on top of horizontal surfaces and electrostatically
clings to the sides of glass and plastic - an utter mess!
Evaporative humidifiers do
not have that problem since the heavy, non-evaporative elements never leave the unit. Instead,
they collect on the filter/dispersion grid. Cleaning or replacement is needed, but at least
the crud is not all over everything else.
You can buy free-standing humidifiers of both
types that have water supply line hookups with valves that regulate water inflow, but you need
to have them located near a supply line. Regardless of the type, you will be listening to fans
blowing all day and night long.
The preferred option, IMHO, is to install a whole-house
humidifier that resides on the furnace ductwork, has its own regulated water supply, and is
controlled by a humidistat. After a couple weeks of refilling three free-standing humidifiers
two to three times a day and listening to the fans, I decided it would be worth the expense
and effort to install a whole-house humidifier. The free-standing units cost $60 at Walmart
($180 total), and the Honeywell HE240A whole-house humidifier with a couple additional parts
cost a total of around $225 at Home Depot. I already had the small sump pump to handle the water
drain, so that saved me $40. I could have run the drain line into the garage floor drain, but
that would have looked bad. So, after about six hours of installation time and an additional
$50, I now have an automatic humidifier that waters itself and probably adds at least $225 of
resale value to my house. The three free-standing units, which would have no resale value, were
cleaned and returned to Walmart for a full refund.
Installation is very simple if you
have all the needed tools, which I did. Instructions called for a 3/4" diameter metal drill,
but I instead marked off a 3/4" hole and drilled around the perimeter with a 3/32" bit and filed
the edges smooth. Because of the vertical downward flow of my furnace, I needed to mount the
humidifier unit on the return air duct. Here are a few photos of the installation in case you
want to try a similar installation for yourself. I'm guessing anyone who reads this, being an
RF Cafe visitor, will have no problem.
Posted February 20, 2014
Here is the completed whole-house humidifier system installation. My house is only 960
ft2, so the Honeywell model
HE240A, which handles up to 1,500 ft2, has plenty of capacity to spare.
Use a level to mark a reference line. Don't measure relative to the duct because it might
not be level or plumb. The humidifier body needs to be level to assure proper drainage.
Drill 1/2" holes at the four corners and use metal snips to cut the hole, then use pliers
to flatten the edges where the snips curled them.
Hang the humidifier body on the bottom of the duct opening.
Level before installing screws. I needed to swap the left and right sides for my configuration.
Mark and cut the humidistat hole.
Mark and cut hole in duct for 6" diameter duct tap. Pressure switch tap requires 3/4"
hole with a grommet and nipple for hose.
Although not required, I looped the water line around the heat duct to pre-heat the water
before entering the humidifier.
Tap installed on cold water supply pipe (same type as for refrigerator ice maker).
Insulation wrapped around duct and water line.
Details of pneumatic, hydraulic, and electrical hookups.
Whole-house humidifier installation overhead view. The sump pump has a 1/2" hose running
over to my washing machine drain pipe (about 20' away).
Whole-house humidifier installation front view.
|Greetings Norman: I'm not a Facebook regular but it appears you have a lot of
connections with the old SSHS clan. You might be interested in these scans from the
Class of '76 year book that I put on my hobby website. If you think it's worth posting
the hyperlink, please do, or I can e-mail you whatever photos you might want and you can
post them on your Facebook account. I'm not in any of the photos, so there's no
self-serving aspect involved.
Note: High efficiency fuel-fired furnaces generate water in the exhaust due to condensation
from the air. It is the same process that condenses air in your air conditioner. It needs
to be drained properly. Mine originally drained into the soil under the house, but I re-routed
it into the sump pump used for the humidifier drain.
BTW, my furnace uses natural gas - the cheapest of all fuel sources these days. I pity
those who use oil, LP, or propane!