To estimate the operating cost for a single cooling season, multiply the capacity of the air conditioner (in Btu per hour), times your electric rate (expressed as a fraction of a dollar per kilowatt hour), times the estimated number of hours of operation. Then, divide this product by the S.E.E.R. (Seasonal Energy Efficiency Ratio) rating multiplied by 1,000.
For example, an air conditioner rated at 10 S.E.E.R. with a capacity of 30,000 Btu per hour and an electric rate of 10 cents per kilowatt-hour (kwh) would cost 30 cents per hour to operate. At 1,000 hours of operation per cooling season, the seasonal operating cost would be $300. The same unit with a S.E.E.R. of 12 would have a seasonal operating cost of $250.
S.E.E.R. is a standard efficiency rating applied to all air conditioners. Ratings for new air conditioners can range from 10 to 16. The higher the number, the more efficient the air conditioner. A typical S.E.E.R. rating for an older air conditioner might be 6 to 8.
"Accurately estimating the hours of operation is difficult, but as a guideline, use 500 hours for occasional use, 750 hours for frequent use, and 1,000 hours for constant or 'on-demand' use," Walter said.
For comparison purposes, it is important to use the same number of hours in all calculations. Likewise, make sure you are comparing air conditioners of equal cooling capacity.
Once you have computed the seasonal operating costs for each model of efficiency, you can compare the difference in operating costs with the difference in purchase costs.
"If a high efficiency model costs $250 more to purchase, but saves $50 dollars per year in operating costs, the higher initial cost would be recovered in five years," Walter said.
The attachment on my vacuum is not long enough to clean to the back of my refrigerator's condenser. What is the best way to clean the condenser?
"Vacuuming is a very good way to clean the condenser," said Gene Meyer, extension specialist in small business energy at Kansas State University.
If the flat attachment is not long enough to reach the back of the condenser, however, you can make a tool from a piece of thin-walled, one and one-half inch pipe. This is available from hardware stores or automotive muffler shops.
"The pipe must be flattened in a vise or with a hammer so it fits between the rows of coils in the condenser," Meyer said. "Leave one end round to slip on the hose of the vacuum."
You can also use a brush similar to a bottle brush, but with a longer handle. The coils should be vacuumed, however, after brushing.
"Be sure to shut off the refrigerator before cleaning to avoid damaging the unit and for personal safety," Meyer said.
July 14, 1996
After connecting to the rural water district, I now have a low capacity well that is not used. Is there any way I can use this well to enhance the heating or cooling efficiency of my home?
Depending on the capacity and the quality of the water, it may be used to provide heating and cooling for your home.
"If the water is soft and low on deposits, it can be used to supply an open loop water source heat pump," said Dennis Matteson, extension specialist in small business energy at Kansas State University.
The water then can be injected back into an injection well. The quantity of water needed is two to three gallons per ton, 12,000 Btu of heating or cooling.
"If the well is low in capacity but deep, another method would be to put a closed looped water source heat pump in the existing well," Matteson said.
By putting in a closed loop system, you minimize water contamination, and you can use the ground as a heat source for both heating and cooling.
"The advantage of the water source heat pump is that in the heating and cooling modes, you typically are able to deliver between three to four Btu of heating or cooling for each Btu of electrical energy purchased," Matteson said.
This means that for every kilowatt hour of electricity, you get approximately 10,000 Btu of heating or cooling; with the conventional resistance electric heating, you would get only 3,413 Btu of heat for each kilowatt hour of electricity.
"If your well will provide only 50 percent of the heating load, it will still provide heat for more than 75 percent of the winter and may reduce your heating costs by more than 50 percent," Matteson said.
You may also reduce your air conditioning cost by about 30 percent due to the increased efficiency.
Will adding insulation to an already insulated surface decrease its overall R-value?
"Adding loose-fill or flexible insulation such as cellulose or fiber glass over existing insulation will only slightly compress the existing insulation, and the loss in R-value will be insignificant," said Richard B. Hayter, director of Engineering Extension programs at Kansas State University.
You should take care that new insulation added to existing insulation does not have a vapor barrier. It could trap moisture in the old insulation.
The benefit of adding more insulation over the old far overshadows any minor loss due to compression of the old insulation.
July 21, 1996
What maintenance is required for satisfactory operation of my evaporative coolers?
Proper maintenance is critical to the satisfactory operation of evaporative coolers. Unfortunately, improper maintenance can lead users to assume that an evaporative cooler is not a practical alternative to cooling.
"Simple maintenance techniques performed before and during the cooling season can increase the efficient operation of an evaporative cooler," said Richard B. Hayter, director of Engineering Extension at Kansas State University.
What are the costs of operating fans and air conditioner?
"The costs of operation are determined by the wattage of the various devices," said Bruce Snead, extension specialist in residential energy at Kansas State University.
Based on one hour of use, with electricity costing eight cents per kilowatt-hour, the total costs are figured for the following cooling units:
July 28, 1996
What is radon?
"Radon is an invisible, tasteless, odorless, radioactive gas that exists in nature," said Bruce Snead extension specialist in residential energy at Kansas State University.
It has always been present in the earth's atmosphere. Although its outdoor concentration is not increasing, this gas has recently received considerable attention because it is has been identified as a potential indoor air pollutant.
"We cannot prevent the production of radon gas; this is a natural phenomenon," Snead said.
Fortunately, it is possible to measure the concentration of the gas in the air and estimate the hazard associated with the radiation emitted by the gas and — more important — its radioactive decay products, Snead said.
Radon gas is constantly, but indirectly, being produced by the decay of uranium-238. Uranium is a natural element found in the earth's crust.
During its slow rate of decay, a nucleus of uranium-238 emits an alpha particle and is transformed into thorium-234, which is also radioactive. This process continues until radon-222 is produced by the decay of radium-226.
"Hence, when people mention radon, they are referring to radon-222 gas," Snead said.
Being an inert gas, radon can migrate away from the location of its uranium parent. If the radon gas reaches the surface of the ground, it will quickly mix with the other gases in the air.
"Increased risk of developing lung cancer is the only established health risk stemming from excessive exposure to the radiation emitted by the decay products of radon," Snead said.
The first step in the production of these decay products starts as soon as the unstable radon-222 atom decays. During each decay, the number of protons in the nucleus is decreased by two as an alpha particle is ejected.
Consequently, the radon atom, with a half life of only 3.8 days, is converted into a different radioactive isotope, polonium-218. As polonium-218 and its daughters decay, a succession of additional radioisotopes is produced. Each emits alpha particles, beta particles or gamma rays.
Because these daughters are chemically active, they can easily become attached to dust particles, solid surfaces such as the interior walls of houses, and if inhaled, to the tissues of the lungs.
"Even though radon is responsible for the production of these decay products, the radon decay products are responsible for most of the concern about health effects associated with high indoor radon levels," Snead said.