The four most common types of roam humidifiers are evaporative, cool mist, steam, and ultrasonic.

Evaporative humidifiers have a fibrous belt that rotates through a reservoir of water. Air is blown through the part of the belt exposed above the reservoir, adding moisture to the air as the water evaporates.

"This type of humidifier can hold up to 10 gallons of water," Walter said. "It is useful for humidifying several rooms without constantly having to refill the humidifier."

Cool mist vaporizers send small droplets of water into the air by stirring up the reservoir with an impeller. Steam vaporizers boil the water just before it enters the air stream, causing it to turn to steam.

"Cool mist and steam vaporizers are useful for humidifying a single room, usually a bedroom," Walter said.

Although inexpensive, cool mist vaporizers are noisy and can saturate nearby objects and surfaces with moisture.

"If they are not properly cleaned and maintained, they can provide a breeding ground for bacteria," Walter said.

The bacteria can be expelled into the air stream with the water droplets. Steam vaporizers, however, kill bacteria in the water and are very quiet, but the steam mist can scald an unsuspecting child.

Ultrasonic humidifiers also are used primarily for single rooms. Vapor is added to the air by vibrating the water with very high frequency sound. "Utrasonic humidifiers must be emptied and cleaned regularly to avoid bacteria problems," Walter said.

The high frequency sound used by ultrasonic humidifiers is inaudible, allowing ultrasonic humidifiers to operate very quietly.

"Both ultrasonic humidifiers and cool mist vaporizers can leave a mineral film on nearby surfaces," Walter said.

Mineral deposits are carried by the particles of water added to the air stream passing in the vaporizer. Belt type of humidifiers and steam vaporizers typically do not have this problem, but are prone to mineral deposits accumulating on the belt or in the tank.

“All but evaporative humidifiers are capable of creating extremely high humidity levels in a closed room,” Walter said. “This may be beneficial for a child with a respiratory illness, but you should take care to avoid prolonged elevated humidity levels as this may cause excessive condensation on windows and hidden condensation inside exterior walls.”

December 10, 1995
What routine maintenance should I perform on my humidifier?
"Regardless of the type of humidifier you have in your home, regular maintenance is necessary for proper operation and health reasons," said Richard B. Hayter, director of Engineering Extension at Kansas State University.

Depending on the mineral content of the water used in your humidifier, precipitated solids may develop and clog small water nozzles, block evaporative elements, and inhibit proper operation of moving parts within the humidifier.

These precipitated solids may be discharged from the humidifier and distribute white dust into the home.

"Follow the manufacturer's recommendation for cleaning your particular humidifier, and do so frequently," Hayter said. "Cleaning two or three times during the heating season and upon shut down in the spring will help remove any build up of precipitates."

Some humidifiers have evaporative elements that can be replaced; others constantly flush the humidifier and discharge any concentration of salts to a floor drain.

Stagnant water left standing in humidifiers provides a fertile breeding ground for bacteria linked to odor as well as respiratory ailments.

"Under worst case conditions, legionella, the bacteria producing Legionnaire's disease, has been found in stagnant humidifiers," Hayter said. "Thoroughly cleaning the humidifier in the spring can help avoid these problems." The louvers below our whole-house fan are very cold and appear to let a lot of heat escape. How can I insulate the fan?
“The metal louvers under a whole-house fan offer little protection against heat loss to the attic in winter,” said Doug Walter, extension specialist in residential energy at Kansas State University.

According to Walter, the most effective way to reduce heat loss is to build an insulated box that can be placed over the entire fan from the attic side. The box should be sealed tightly to the framework that supports the fan. You can attach insulation directly to the box or simply drape it over the box.

“If access to your attic is difficult, you might want to consider placing an insulated panel directly above the louvers or attaching it beneath them,” he said.

Walter added that taping a sheet of plastic over the louvers will stop the warm air that leaks through them in the winter. This alone will provide a significant savings. Many hardware and discount stores have specials kits for sealing whole-house fans that can be reused. December 17, 1995
Does foundation insulation make it easier for termites to find a way into my house?
"The best protection from termites is to insulate on the inside of your foundation," said Tom Logan, energy specialist in Engineering Extension at Kansas State University. Exterior insulation is approximately 10 to 20 percent more energy efficient than interior, but termites have been known to attack polystyrene and polyurethane foam boards, the most commonly recommended exterior foundation insulations.

"The termites don't eat the insulation," Logan said. "They burrow into it to warm themselves, and in turn, may find a hidden access to your home."

If you have already installed exterior insulation, then try to keep the soil around your foundation dry because termites cannot live without water. This is done by grading you lawn so it slopes away from your house, sending water from your gutters into storm sewers or a drainage well, or installing drain tiles outside the footings of your foundation.

"Drain tiles are expensive, but may be worth the cost if the soil around your basement is frequently damp," Logan said.

Do not stack firewood next to your foundation, and keep wood scraps and dead limbs away from your house.

"If termites persist, then you may have to treat your foundation with chemicals," Logan said.

The standard termite chemicals, chlorinated hydrocarbons, are very toxic. These include aldrin, dieldrin, and heptachlor. Chlordane is now prohibited from use.

"Some new termite chemicals, organophosphates, have been developed which are less toxic than the chlorinated hydrocarbons, but do not last as long," Logan said. What is dry rot?
"Dry rot refers to wood that has decayed after becoming wet and then drying," said Doug Walter, extension specialist in residential energy at Kansas State University. “Although the rot may be observed in dry wood, the decay occurs only when the wood is wet.”

Dry rot is usually associated with a seasonal moisture problem, such as condensation in walls during cold weather, which allows rotcausing fungi to grow only for a short time, resulting in a slow progression of the rot.

"Dry rot can be prevented by eliminating sources of moisture and dampness, ventilating damageprone areas, and by restricting moisture flow with vapor barriers," Walter said. December 24, 1995
What are the clearances required for installing a woodburning stove?
"To be used safely, stoves must have adequate clearances from all combustible materials," said Bruce Snead, extension specialist in residential energy at Kansas State University.

Adequate clearance is especially important for stoves used continuously as the primary source of space heat, or those that are fired to burn extremely hot. A typical woodburning stove should have 36inch clearances around the top, sides, front, and back from all combustible materials.

"Using fireproof shielding, such as asbestos mill board spaced out one inch from the combustible surface, can reduce these clearances to 18 inches," Snead said.

A combustible floor should have an 18inch clearance from the bottom of the stove. or a fourinch clearance if protected by a covering, such as brick or tile. which shields the floor from heat and ashes. Some stoves have reduced clearance requirements due to the nature of their construction. Check manufacturer's labels or safety literature for safe distances.

"Singlewall stovepipe should be installed with a minimum 18inch clearance from all combustible materials," Snead said.

Insulated metal chimneys usually are tested by Underwriter's Laboratories Inc.. or other nationally approved laboratories. and minimum clearances from combustible materials are marked on each section. Minimum clearance is usually two inches. I just discovered that my furnace has been operating without a filter for more than a year. Has this harmed my furnace?
"A furnace filter serves two purposes," said Gene Meyer, extension specialist in small business energy at Kansas State University. "It reduces the amount of dirt circulated into the house and helps keep the dirt from accumulating inside your furnace."

Dirt accumulation within the furnace will reduce the performance of the equipment. "If your furnace has operated for an entire year without a filter, its performance may be reduced because dirt has accumulated on the heat exchanger on fan surfaces," Meyer said.

A service technician can inspect the heat exchanger and fan to determine if enough dirt has built up to warrant a thorough cleaning. In all probability, a single year's operation without a filter will not have significantly affected your furnace's performance. December 31, 1995
How can I install a vapor barrier on an existing wall where insulation has been blown in between the studs?
"In existing homes, the most convenient approach is to use a vapor barrier paint on the interior surfaces of the walls and ceiling," said Bruce Snead, extension specialist in residential energy at Kansas State University.

Although this paint is more permeable than polyethylene and other vapor barrier materials, it should be adequate for most homes unless unusually high moisture conditions exist. Before applying vapor barrier paint, you should seal joints, cracks, and other cavities that would allow moisture into the home.

"Seal inside the house for the best protection and energy conservation results," Snead said.

Many paints now are designed for use as vapor barriers either as primers or finish coats. They can be applied in the same way as other paints and come in both oil and latex bases. Almost any type of paint can be used for a finish coat.

"These special paints do not cost more than top quality interior paints and present an excellent way to obtain a vapor barrier without major interior renovation," Snead said. Should I insulate the pipes in my hot water heating system?
“Two conditions must be evaluated before you decide to insulate the pipes in a steam or hot water heating system,” said Gene Meyer, extension mechanical engineer at Kansas State University.

If the pipes run through an unheated area, these sections should be insulated. If you have overheating in certain areas of the building as a result of heat given off by bare pipes, then these areas should be insulated as well. If all the piping runs through heated areas and no overheating occurs, there is no benefit to insulating these lines.

The amount of insulation you install depends on the temperature and the size of the line. Steam lines two inches and less should have 1 1/2 inches of fiber glass insulation. Hot water heating systems, because they operate at lower temperatures, should have one inch of insulation.

“You should also evaluate the domestic hot water lines for the benefit of insulation as well,” Meyer said. “If there are long runs of hot water lines through unheated spaces, insulation would increase the delivery temperature at the faucet.”

To obtain the same delivery temperature at the faucet, it would be possible, by using insulation on the lines, to reduce the setting of your water heater a few degrees, thus saving energy on that appliance.

“Insulation on domestic hot water lines will not keep the water hot for extended periods of time, but will reduce the heat loss from the lines while water is flowing,” Meyer said.