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"The old cast iron radiators are nearly as efficient as baseboard models," said Gene Meyer, extension mechanical engineer at Kansas State University. "Because the surface area is smaller on cast iron radiators than the fin tube models, the boiler may have to operate at a higher temperature, causing some reduced efficiency. In addition, fin tube convectors are usually supplied along a greater length of the wall, providing more uniform heating."
This tends to improve comfort.
One problem often encountered in old cast iron systems is that the walls are uninsulated behind the radiators.
"By placing the heat source directly against an uninsulated wall, considerable heat is lost to the outside," Meyer said.
One method of improving this situation is to install a thin, rigid foam insulation board directly behind the radiator and covering the board with a one-half inch layer of sheet rock.
"This insulates the wall directly behind the radiator and allows more of the heat to be used within the space," Meyer said.
It is important to install the sheet rock over the rigid insulation in order to conform to fire codes related to covering of foam insulation products.
"Another suggestion is to use dull and preferably dark-colored paint on the radiator," Meyer said.
The use of shiny aluminum-colored paint is not recommended. A dark surface is a better radiator than a bright, shiny surface.
"Vent area is determined by a ratio of one square inch of vent area per square foot of attic floor area," said Bruce Snead, extension specialist in residential energy at Kansas State University.
Your house requires adequate attic ventilation in order to keep attic temperatures as close to outdoor summer temperatures as possible. In the winter, ventilation provides for the release of moisture that may find its way into the attic.
"Passive ventilation, through the proper placement of vents, is the best method," Snead said.
Half the vents should be low, or soffit vents, and half should be high, or ridge vents.
"Continuous ridge venting is the most effective because it works regardless of wind direction," Snead said. "Check the venting device for its ‘free vent area’ rating to be sure you are getting sufficient area."
"A ground-coupled heat pump is a cooling and heating device that uses the earth as a source or dissipator of heat," said Dennis Matteson, extension mechanical engineer at Kansas State University.
There are two basic types: closed loop and open loop water systems.
"A closed loop system circulates the same water through pipes buried in the ground," Matteson said. "This type of system is used where the water table is deep or has a high mineral content."
The water loops can be either vertical wells or horizontal pipes buried 5 to 8 feet below the ground's surface.
"Open loop systems can be used where water quality is good and plentiful," Matteson said. "Flow rates are typically two to three gallons per minute for each ton of capacity."
The flow rate will vary depending on the water table temperature.
"The main advantage of ground-coupled systems is their nearly constant temperatures. These temperatures enable the system to operate at full capacity during extreme outside air temperatures." Matteson said.
Heat pumps that use the air as a source or dissipator of heat decrease in efficiency at extreme air temperatures, he said.
"In the long run, a gas dryer is cheaper," said Bruce Snead, extension specialist in residential energy at Kansas State University.
The purchase price for a gas dryer is generally $35 to $50 more than a comparable electric dryer. Installation costs also will be higher because of the gas line connection.
"You will recover these initial costs through the lower operating costs associated with a gas dryer," Snead said.
Based on average electric and gas rates for Kansas, a gas dryer provides the same amount of drying time for less than half the cost.
"How much you use your dryer will determine how quickly you recover those higher initial costs for a gas unit," Snead said.
Under typical conditions, a gas dryer will pay for itself in savings within one or two years, he said.
"A house is a dynamic system where heat, humidity and air motion interact with materials and people. Homeowners need to understand these elements and their relationships in order to construct a better, more energy-efficient house," said Bruce Snead, extension specialist in residential energy at Kansas State University.
A vapor barrier allows less air infiltration and may reduce the square inches of vents needed to remove moisture from an attic.
A well-installed ceiling vapor barrier, sealed at corners, laps and penetrations, will lead to a tighter, more energy efficient house, Snead said.
"The costs of material (usually 6 mil polyethylene), and installation are minor," Snead said, "so the question is really one of appropriateness and necessity."
The value of a vapor barrier in a new home is an issue debated constantly by builders and designers, Snead said.
"Some builders view a vapor barrier as a moisture trap which leads to moisture problems, such as sheet rock nails popping, and can result in call-backs," Snead said. "Others see a barrier as a necessary element in an energy-efficient house."
Homes without a ceiling vapor barrier need maximum attic ventilation. Cathedral ceilings, in particular, can be difficult to ventilate, and need an effective ceiling vapor barrier to prevent moisture from being trapped under shingles.
Problems with ceiling vapor barriers usually result from inadequate ventilation or curing of moisture laden construction materials. "Concrete, sheet rock and wood all release moisture which must be vented," Snead said. Air temperatures and exposure to heat will affect moisture levels during construction and the curing rate afterward.
Problems may occur when weather or builders create conditions in which moisture from construction materials is not released from a building.
"A new home will continue to cure during the first one or two years, and increased ventilation, or dehumidification, may be necessary," Snead said. "The more tightly built a home is, the more it will require venting to release moisture generated by normal household activities such as bathing and cooking."
"The services provided during a furnace tune-up will depend on the service agency," said Dennis Matteson, extension specialist in small business energy at Kansas State University. "Most service personnel, however, will check the items below."
- Pilot light: Should be checked and cleaned if necessary. The pilot light ignites the main combustion process in the furnace. If it uses a standing, or continuous flame, the thermocouple should be checked and replaced if it is defective.
If the pilot is a solid state device, the pilot ignition process should be checked and the pilot cleaned if necessary.
- Burners: Should be checked visually to see if they need cleaning. If cleaning is necessary, the burners should be removed, vacuumed and brushed to remove any rust or other debris from the burner itself.
- Heat exchanger: It is also critical to visually inspect the surfaces of the heat exchanger to determine if there are any cracks or other potentially dangerous problems with the furnace.
The heat exchanger should be checked under full load of the furnace because some cracks become apparent only when the furnace is heated and the metal is forced to expand.
- Chimney: After the furnace is turned on, the chimney should be tested to insure that it is drafting correctly and to determine if there is enough air for clean burning in the combustion chamber.
- Exhaust fans: If there are exhaust fans or other devices in the furnace area that could cause negative pressure, these devices should be turned on and the draft checked.
- Motors and blower fans: Should be oiled and checked for proper belt tightness and slack in their bearings.
- Thermostat: Should be checked for accuracy and proper setting of the anticipator. The anticipator prevents the temperature from overshooting when the furnace operates for a period of time. If the anticipator is set, the furnace is not reaching the desired set point, or the temperature fluctuation in the room may be quite high.
"Anyone who has a furnace that has not been inspected for two or three years should consider giving it a routine tune-up," Matteson said. "Many people have found that annual inspections can save service calls during the time of the year when they need the furnace the most—and service is most difficult to obtain."