Ask Energenie

February 1998


Table of Contents

  1. Is it possible to use biomass as an alternative energy source for the state of Kansas?
  2. Would you advise using an old masonry chimney for venting a new gas furnace or water heater?
  3. What are radon's risks?
  4. 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?
  5. How much can I really save by setting back my thermostat?
  6. Will a heat pump, which is about twice as efficient as a gas furnace, cost less than a gas furnace to provide the same amount of heat?
  7. I have a portable, evaporative type of humidifier. It gives off a bad smell when I operate it. If I completely replace the water in the tank, the bad smell returns within several days. What causes this and how can I prevent it?
  8. How does radon occur?

| Return to Ask Energenie home page |


1. Is it possible to use biomass as an alternative energy source for the state of Kansas?

"Yes, our state has the potential to use biomass as an alternative energy source," said Richard Nelson, extension specialist in energy at Kansas State University.

"Biomass is the organic matter that results from plant and animal growth. Kansas has an abundant supply of biomass in some forest products and in agricultural crop residues," said Nelson.

Wheat straw and wheat dust are two types of crop residue that can be used for biomass production.

"From an agricultural standpoint, it is possible to remove a portion of the wheat straw without affecting conservation or nutrients of the soil," said Nelson.

The other type of agricultural crop residue, wheat dust, is the finely divided matter generated as grain is handled from field to elevator. Most elevators dispose of this dust because it is a safety hazard.

"Together, the crop residues, wheat straw and wheat dust, contain approximately one-half to two-thirds the heating value of coal," said Nelson. "The collected wheat straw or dust could then be used with coal as a fuel source in a typical generating plant."

Another potential application of these agricultural crop residues involves burning the fuels by themselves to provide heat on a smaller scale, such as for the drying of grain.

Other forms of biomass that could be used for energy purposes include wood wastes from sawmills or wood-finishing operations and wastes from agricultural food processing operations.

Back to Top

2. Would you advise using an old masonry chimney for venting a new gas furnace or water heater?

"The National Fire Code does not specifically prohibit the use of masonry chimneys with modern gas appliances," said Gene Meyer, extension mechanical engineer at Kansas State University. "However, you must line the chimney with an approved material."

Meyer said many old masonry chimneys are not lined. Venting gas appliances into unlined chimneys could cause drafting problems for the appliance as well as deterioration of the masonry.

"I recommend you vent gas appliances with a properly sized and designed chimney," Meyer said. "Check with your local building code officials for their specific requirements."

Back to Top

3. What are radon's risks?

"The only well-documented risk of exposure to radon gas and its radioactive decay products is increased potential for developing lung cancer," said Bruce Snead, extension specialist in residential energy at Kansas State University.

The EPA classifies radon as a Class A carcinogen, which means it is a known human carcinogen.

"Radon exists in all environments, indoors and out," Snead said. "Our exposure is a function of how much time we spend in various radon levels."

Radioactive decay from radon decay products can occur inside our lungs.

"The emissions from this process are like tiny atomic bullets, creating chemical and physical changes in the DNA of living lung cells," Snead said.

"Sometimes the cells die, sometimes they repair themselves and sometimes they mutate and grow, potentially forming cancer," Snead said.

No other significant health effects of radon exposure have been established. Radon provides no immediate indicators of exposure because it is odorless, tasteless and colorless and human senses cannot detect it.

Back to Top

4. 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, president of Kansas Building Science Institute, Manhattan.

According to Walter, the most effective way to reduce heat loss is to build an insulated box that you can place over the entire fan from the attic side. You should seal the box tightly to the framework supporting the fan. You can attach insulation directly to the box or simply drape it over the box. Be sure to disconnect power to the fan so it can't be turned on inadvertantly while the cover is in place.

"If access to your attic is too difficult to allow you to install such a box, you might want to consider attaching an insulated panel directly below the louvers," he said.

To make this an easy seasonal task, build a permanent frame around the louvers using 1x2-inch lumber to hold the insulated panel.

"You can cut the panel from five-eights-inch rigid insulation board and cover it with white sticky-backed shelf paper to make it blend in with your ceiling," Walter said. "Four wing-nuts mounted in the frame will hold the panel in place."

Walter added that taping a sheet of plastic under the louvers will help stop air leakage but will provide little insulation.

Back to Top

5. How much can I really save by setting back my thermostat?

"Turning back the thermostat is one of the more effective energy-conserving steps you can take in your home," said Bruce Snead,extension specialist in residential energy at Kansas State University.

"Each degree you permanently lower your thermostat setting will save you about three percent on your heating expense," Snead said.

If you now keep your thermostat at 72 degrees F all of the time, you could save about six percent on your heating bills by lowering thesetting to 70 degrees. You could save about 15 percent with a setting of67 degrees.

"Each degree you set the thermostat back for only eight hours every night will save about one percent on your heating cost," Snead said.

"For example, if you now leave your thermostat set at 72 degrees all the time, you could save about five percent by setting it to 67 degrees for eight hours every night," he said. "And 10 percent can be saved by turning it down to 62 degrees every night," Snead said.

The cost of the extra running time for the furnace in the morning is insignificant compared with the savings.

"But with some heat pumps, nighttime setback may be counterproductive," Snead said.

Timers that can set and reset thermostats automatically are available in many stores.

Back to Top

6. Will a heat pump, which is about twice as efficient as a gas furnace, cost less than a gas furnace to provide the same amount of heat?

"The two units are receiving their energy in different forms," said Dennis Matteson, extension mechanical engineer at Kansas StateUniversity.

Heat pumps operate on electricity and gas furnaces consume naturalgas. Differences in fuel prices and differing efficiencies both impact the cost of delivering heat.

"At current natural gas prices of about $5 per 1,000 cubic feet, a dollar's worth of natural gas can produce about 200,000 British thermal units (Btu)," he said. "That is, if you could extract all available energy. If you have a furnace operating at 70 percentefficiency, it delivers about 140,000 Btu for each dollar spent on fuel. A high efficiency furnace might deliver 190,000 Btu for each dollar spent."

A typical heat pump delivers about twice as much energy as it consumes. Average residential electric prices are about 7 cents per kilowatt-hour. Often electric utility companies offer lower electric rates for all electric homes. Using an electric rate of 4 cents per kilowatt-hour, a dollar will buy about 170,000 Btu. If prices are 7 cents per kilowatt-hour, the heat delivered is reduced to 97,500 Btu per dollar spent

"As you can see, both energy prices and equipment performance together determine the cost of delivering heat to home," Matteson said.

Back to Top

7. I have a portable, evaporative type of humidifier. It gives off a bad smell when I operate it. If I completely replace the water in the tank, the bad smell returns within several days. What causes this and how can I prevent it?

"Bacteria growing in the water is most likely causing the odor," said Doug Walter, president of Kansas Building Science Institute, Manhattan. "The bacteria comes from air-borne dust that is drawn through the humidifier by the fan."

Standing, room-temperature water provides an ideal growing medium for bacteria, Walter said.

To prevent bacteria from growing, completely empty and replenish the water tank daily, or add an algaecide to the water in the humidifier reservoir.

"Because daily emptying of an evaporative humidifier can be difficult and cumbersome (some models hold 10 gallons or more), using an algaecide is probably more practical," Walter said.

Algaecides are available at most stores where humidifiers are sold.

"If you have been operating your humidifier for some time without using an algaecide," Walter said, "you may need to thoroughly clean or replace the evaporator belt to eliminate the odor entirely."

Walter cautioned that manufacturers do not recommend algaecides for use in ultrasonic humidifiers, cool mist vaporizers, steam vaporizers or any type of humidifier that actually atomizes water droplets.

Back to Top

8. How does radon occur?

"Radon occurs from the natural radioactive decay of radium," said Bruce Snead, extension specialist in residential energy at Kansas State University. "It is present in the soil everywhere in greater or lesser concentrations."

Radium provides a long-lived, relatively constant source for radon.

"Because radon is an inert gas, it can be drawn through the soil by various air pressure differences," Snead said, "and can find its way into buildings through openings in the foundation."

| Back to Top | Home |

Ask Energenie is produced by the Kansas Energy Extension Service through Kansas State University. This material was prepared with the support of the U.S. Department of Energy (DOE) Grant No. DE-FG47-92-CE60210. However, any opinions, findings, conclusions, or recommendations expressed herein are those of the author(s) and do not necessarily reflect the view of DOE.
Mike Dorcey
Editor
Extension Engineering
Kansas State University
133 Ward Hall
Manhattan, KS 66506-2508
913-532-6026
mdorcey@oz.oznet.ksu.edu