Update Bulletin No. 649
www.dulley.com
Jim Dulley
T
hank you for
your interest
in writing to me about
using a humidifier to keep
your house more comfort-
able, protect it from dam-
age and lower your heat-
ing bills. A humidifier
lowers your heating bills
by allowing you to set your furnace thermo-
stat lower without feeling chilly. When the
room air is overly dry, the moisture from
your skin evaporates quickly and this cools
you similar to sweating. The chart below
will give you a rough idea of the capacity of
humidifier you will need. Very cold cli-
mates often need slightly larger humidifiers
and very mild areas need slightly smaller
ones.
On the following pages, I have
listed manufacturers of the high-
est quality humidifiers for home
use. Page four shows an excellent
description of the advantages and dis-
advantages of the most common de-
signs of humidifiers you will find at
NOTE: If there is uncertainty as to the type of home construction, the values shown in the average
category may be used.
*Humidification not necessary to maintain conditions of 70
o
F (21.1
o
C) and 30 percent relative humidity
An amount of approximately 2 gallons per 24 hours provided by internal sources of humidity (based on
a family of four) has already been deducted from the above values.
The above chart is based on an indoor temperature of 70
o
F and a wind speed of 15 miles per hour. Use
this only as a guideline. The actual humidity level where condensation forms depends on your specific
window design, special coatings, thickness of air space, and type of gas in between glass panes. The
frame may also begin to sweat before the glass itself.
Maximum Indoor Humidity Level to Avoid Window Condensation
Outdoor Temperature
Maximum Indoor Humidity
Level - Single Pane - %
Maximum Indoor Humidity
Level - Double Pane - %
-30 3 27
-20 6 30
-10 8 35
0 13 40
10 20 46
20 26 52
30 32 59
40 44 68
Humidification Selection Guide
Construction of Residence Size of Residence in Square Feet
500 1000 1500 2000 2500 3000
Water Output Capacity, Gals./24 Hours
Tight — well insulated, vapor barrier, tight storm
doors/windows with weatherstripping, dampered
fireplace
* 1.40 3.20 4.90 6.60 8.30
Average — insulated, vapor barrier, loose storm
doors/windows, dampered fireplace
0.50 3.00 5.50 8.00 10.50 13.00
Loose — little insulation, no storm doors/windows,
no vapor barrier, undampered fireplace
1.00 4.00 7.00 10.00 13.10 16.10
• Empty the tank, wipe all surfaces dry, and re-
fill the water in portable humidifiers daily to
reduce any growth of microorganisms; follow
the mfgs. instructions for changing water in
console humidifiers. Unplug the unit from the
electrical socket first. Use water with low min-
eral content to prevent the buildup of scale and
the dispersal of minerals into the air.
• Clean portable humidifiers every third day.
Empty the tank and use a brush/scrubber to
clean it. Remove any scale, deposits, or film
that has formed on the sides of the tank or on
interior surfaces, and wipe all surfaces dry.
Unplug the unit. Follow the mfgs. suggestions
on the use of cleaning products or disinfec-
tants. In the absence of recommendations,
clean all surfaces coming in contact with wa-
ter with a 3 percent solution of hydrogen per-
oxide. If you use any cleaning or disinfecting
agent, rinse the tank thoroughly with several
changes of tap water to prevent dispersal of
chemicals into the air during use.
• Keep steam vaporizer humidifiers out of the
reach of children. Steam and boiling water may
cause burns.
• Do not permit area around humidifier to be-
come damp. If dampness occurs, turn the out-
put volume down. If output volume cannot be
turned down, use the humidifier intermittently.
Do not allow absorbent materials, such as car-
peting, drapes or table cloths, to become damp.
• If water condenses on windows, walls, or pic-
tures, either relocate the humidifier, lower its
humidistat setting, or reduce its use.
Use and Care Recommendations from
The Environmental Protection Agency
most home centers
and hardware
stores. If you
have small chil-
dren that may have
access to rooms
with the humidifier
in them, it would be wise to avoid the steam
mist (vaporizer) design. The steam outlet
may scald a child’s hand. I use a quiet
ultrasonic model in my bedroom at night and
an evaporative type near my corn/pellet stove
in my living room.
The evaporator designs (pictured above)
generally can have the greatest moisture out-
put. Most larger console models use this
design. A large capacity console model
can easily humidify an entire house. Even
without the furnace blower circulating
the air throughout the house, the
moisture will naturally migrate
to all the rooms.
Even though many humidi-
fiers have antimicrobial treatments
on the wicks, filters and plastic hous-
ings, it is a good idea to clean them regularly
per the manufacturer’s instructions. The
last thing you want is to have mold spores or
bits of bacteria being introduced into the
room air.
In all but the mildest climates, shoot for
a humidity level just slightly less than the
level that causes window condensation. On
colder days, you will have to set the humidi-
fier to run less or get replacement windows
with more efficient glass to avoid condensa-
tion. If you have hard water in your area,
you may find a white powder near an ultra-
sonic humidifier. This is the hard water ion
deposits as the water evaporates in the air.
The prices of humidifiers can range
from as little as $20 for small tabletop
models to more than $100 for large decora-
tive console models. You can find them at
many discount and home center stores and
they are often on sale. Also check the
manufacturers’ web sites for specials. For
example, Holmes Products has some
discounted special items which
they sell online.
Typical evaporator
(12 pages)
(102 pages)
(8 pages)
Manymanuals.com
Manymanuals.de
Manymanuals.fr
Manymanuals.it
Manymanuals.pl
Manymanuals.cz
Manymanuals.es
Manymanuals-pt.com
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