By Douglas Burgasser
Residential humidifiers have gained a great deal of popularity in recent years. They have become quite common in houses that are heated with forced air heating systems. Unfortunately, many homeowners do not understand how their humidifier works, how is gets adjusted, and how it should be maintained. Some homeowners might not even realize they have a central humidifier.
TYPICAL MODERN HUMIDIFIER
As you are probably aware, indoor air tends to be somewhat dry during the winter season in the Rochester area. This is because it is cold and dry outside. As a result, it is beneficial to introduce some moisture or humidity into the living space. This can be accomplished through the use of a standard air humidifier that is installed on a forced air heating system.
Older style humidifiers consisted of a sponge-like media material that was mounted on a drum or wheel. A small motor turned the wheel, allowing the media to become saturated as it passed through a small basin of water. Air from the heating system passed through the humidifier, introducing moisture to the air. This style humidifier tended to be problematic since it relied on the operation of a small motor and a small float valve. Also, there was constantly a basin of standing water, which eventually would become dirty and filled with mineral deposits.
The following photos show various old style humidifiers, the last of which is leaking:
PAD STYLE
OLD DRUM STYLE
BRUSH STYLE
OLD APRILAIRE
LEAKING DRUM HUMIDIFIER
Modern style humidifiers are simple devices. They consist of a water supply (controlled by an electric solenoid valve) which trickles water through a “water panel”. As is the case with the older style humidifiers, moisture is introduced to the air as it passes through the humidifier. However, with these modern units, excess water is immediately drained out of the system. As a result, the maintenance on these systems is minimal. The water panel should be replaced annually.
WATER FLOW INTO HUMIDIFIER
Humidifiers operate automatically. They are controlled by humidistats. A homeowner simply needs to adjust the humidistat to their desired humidity level. Humidifiers are typically wired so that they will only operate during the heating cycle. The humidifier will then function if the humidity level of the air in the house is lower than the setting on the humidistat.
People often ask us how they should set their humidistat. A good starting point would be between 30% and 35 % humidity. If a homeowner finds that the inside of the house feels somewhat damp or that there tends to be condensation formation on the windows, they should decrease the setting on the humidistat. Care should be taken to not over-use a humidifier. Excessive amounts of moisture in a house can lead to problems from excess condensation. On the other hand, if the indoor air tends to be too dry (or if a person is being “shocked” as they walk around the house in their stocking feet) the humidistat should be turned up.
HUMIDISTAT
In general, as severely cold temperatures are reached outdoors (such as -20F), the humidifier setting should be changed from 35% to 25% or 15%, to prevent excessive condensation on windows, walls and other surfaces.
The water panel in the humidifier should be changed once each year as maintenance. Sometimes, when the winter is not too cold and dry, the panel can last two years before changing it. Excess minerals in the humidifier can be cleaned out with a solution of white vinegar and then water.
CLEAN WATER PANEL
BUILD-UP OF DEBRIS ON WATER PANEL
VERY DIRTY WATER PANEL!
On most humidifiers or the connected ductwork there is a bypass damper. This damper should be opened during the winter to allow air through the humidifier. In the summer, if you have central air conditioning, the damper should be closed to save fan energy and to get the most out of your air conditioning system.
DAMPER OPEN (WINTER)
DAMPER CLOSED (SUMMER)
Humidifiers, when used properly, can make occupants more comfortable at slightly lower temperatures. This can reduce the thermostat setting and reduce heating costs.
We trust that this brief explanation will provide you with some valuable information regarding the use of a central humidifier in your home.
As is always the case, please do not hesitate to contact our office if we can be of any assistance regarding this topic, or other topics related to your house.