I've seen and heard a lot of advertising about home heating equipment. Some ads imply gas furnaces are best, while others claim heat pumps are more efficient. Does "efficient" mean less costly to operate? Please explain the claims.
A more efficient appliance is not necessarily cheaper to operate although advertising copy often implies that it is.
"The efficiency of a gas furnace is the fraction of the available energy in the gas delivered to the home that is converted to heat," said Dennis Matteson, extension specialist in small business energy at Kansas State University.
Some of the heat generated when the gas is burned goes up the chimney, but most of the heat is delivered to the house, Matteson said.
Gas furnaces typically have efficiencies in the range of 65 to 95 percent. That is, 65 to 95 percent of the energy that could be extracted from the gas is actually delivered to the house as heat.
"A heat pump can deliver more energy to the house as heat than it. The heat pump doesn't create energy. It simply transports energy from a source, such as outside air, and delivers it to the house."
Heat pumps are not rated by efficiency. They are rated by heating season performance factor (HSPF) or the coefficient of performance (COP). "The ratio of energy delivered to the energy consumed is called the coefficient of performance or COP, he said. The COP of an air source heat pump changes as the weather changes, but on the average, an air source heat pump delivers about 1.8 to 2.2 times as much energy to the house as it consumes", he said.
The HSPF is also a ratio of energy delivered to energy consumed. However, the units of energy are Btu delivered and the units for energy consumed are kilowatt-hours (kwh).
"At the point of use, the heat pump is more efficient than the gas furnace," he said.
So how can a heat pump more efficient than a gas furnace and still cost more to operate?
"The two units are receiving their energy in different forms and at different costs", Matteson said.
"With a natural gas price of $5 per 1,000 cubic feet, a dollar's worth of natural gas has a heating value of about 200,000 Btu," he said. "That is, if you could extract all available energy from a dollar's worth of natural gas, you would have about 200,000 Btu. A typical new furnace at 80 percent efficiency can supply 160,000 Btu for each dollar spent on fuel."
Most heat pumps operate on electricity. Using 6 cents per kilowatt-hour for the electric rate, a dollar's worth of electricity has a heat content of approximately 56,867 Btu, he said. A typical heat pump, delivering twice as much energy as it consumes, delivers about 113,733 Btu for each dollar spent on electricity.
Situations exist where a heat pump may be the best choice. For example, a heat pump is certainly preferable to electric-resistance heating, Matteson said. Some utility companies offer lower rates for electricity used for heating. These rates can make the heat pumps less expensive to operate.
Wood stoves are another example of how more efficient appliances are not necessarily cheaper to run, Matteson said. For example, many Kansans save on their heating bills by using wood stoves.
"A wood stove's efficiency may be as low as 30 percent, compared with 65 to 95 percent for a gas furnace.
A wood stove, however, may be cheaper to operate if you have an inexpensive source of wood," Matteson said.
How much could I save by turning down or shutting off my water heater at night when everybody is asleep?
"Regardless of the type of water heater you have, the savings will be between $1 and $3.50 a year," said Gene Meyer, extension specialist in small business energy at Kansas State University.
The exact savings you could expect depend on the type of water heater and the fuel you use.
Unless the device that shuts off or turns down your water heater is inexpensive, shutting off the water heater will not be cost effective.
"If, however, you will be away from home for an extended period, such as a weekend or vacation, the savings will be more significant," Meyer said.
A more effective approach to saving money and energy on hot water is to insulate your water heater with a 3˝-inch thickness of fiberglass insulation.
"You can also buy water heater tank insulation kits that make insulating your water heater a little simpler," Meyer said.
What kind of performance can I expect from a solar water heating system in Kansas?
"Studies have shown that a properly sized active solar water heating system should satisfy 40 to 70 percent of a family's annual energy requirements for heating water," said Bruce Snead, Kansas State University extension specialist in residential energy.
Snead said that during summer months a solar system could provide 80 to 100 percent of the hot water a family might need, but only 30 to 50 percent during winter.
"Of course, the type of system you have and your water consumption habits will also affect performance. But because hot water is a year round need, this can be a cost effective use of solar energy in a residence," Snead said.
However, he added, lack of widespread availability and servicing of solar systems presents a challenge to those who would like to take advantage of this renewable energy application.
Should I cover my attic turbine ventilators in the winter to reduce heat loss?
"A certain amount of attic ventilation is needed year round so moisture generated by cooking, showering. and other activities can escape. It is not just for removing heat during the summer," said Doug Walter extension specialist in residential energy at Kansas State University.
According to Walter, the recommended vent area is one square inch for every square foot of insulated attic area. "If your house has enough ventilation without including existing turbine vents. it is safe to close them during the winter months. The main benefit of doing this is not to reduce heat loss but to extend the life of the vents.
"Turbines should be covered from the outside to protect them from the weather and to keep them from spinning," Walter said.
I'm having my attic insulated. What should I do to the access panel in my ceiling?
"These panels are often single pieces of sheet rock or plywood, neither of which has much of an R-value nor forms a tight seal," said Bruce Snead, residential energy specialist at Kansas State University.
Snead recommends one (two, if possible) layers of six-inch fiberglass insulation stapled to the attic side of the panel. Keep the vapor barrier down, he cautioned, and staple only around the edge.
"You can also use five or six inches of foam board insulation. If you insulate the attic with loose-fill or blow-in insulation, you'll want to put up wooden or cardboard barriers to prevent the loose material from spilling down when you open the panel," Snead said.
It's also important to form an airtight seal around the edges of the panel with weatherstripping. Also, caulk around the opening to close any gaps in the ceiling trim. If necessary, add a latch to pull the door tightly shut.
"The cost of doing this all yourself is around $3, and the measures should pay for themselves within one year," Snead said.
The previous owners of my house installed fiber glass batts in the basement ceiling with the vapor barrier facing down. The basement is heated. Should I take the batts down and reinstall them correctly with the vapor barrier facing up?
"You don't need to remove the insulation in your basement ceiling or change the location of the vapor barrier," said Doug Walter, extension specialist in residential energy at Kansas State University.
Because both the basement and presumably the rooms above are heated, moisture is not likely to condense in the insulation. In fact. it would be a problem only if the basement was not heated.
Vapor barriers should be located on the warm side of insulation. If the basement was not heated, the vapor barrier should be against the flooring above the basement ceiling.
Insulation in floors over unheated basements and crawl spaces often is installed incorrectly with the vapor barrier facing down because it is convenient to use the kraft paper edges to staple the insulation to the bottoms of the floor joists.
Another fastening method to place the vapor barrier against the floor is to use heavy wire stringers wedged between the floor joists under the insulation.
"The heavy wire, cut about a half-inch longer than the width of the joist space, acts as a 'beam' to support the insulation," Walter said. "The wire supports are placed about every 12 to 16 inches along the length of the insulation batts."
Many lumber yards and hardware stores carry or can order precut wires that make the job more convenient.
I've always been told that it takes more power to start a light than it takes to run it for a long time. Could you shed a little light on the benefits of shutting off lights?
If you are using incandescent lights, always shut them off when you leave a room—even if you are going to be gone only a minute or two.
Several years ago, when electrical energy was inexpensive (one cent per kilowatt hour), people left lamps on for extended periods because turning a fluorescent light off and on shortens the life of the lamp a small fraction. "At that time, the cost of the lamp was the most significant part of operating a lighting system," said Gene Meyer, extension specialist in small business energy at Kansas State University. "Since those times, things have changed considerably." Because the energy used to operate that lamp now far exceeds the cost of the lamp itself, whenever you leave a room for more than about seven to 10 minutes, you would be better off to shut off fluorescent lights. "It is my opinion that most times when you leave a room, even if you think you going to be returning shortly, you will be delayed, so shut off those fluorescent lights," Meyer said.