QUESTION: I thought about installing a whole-house fan so I can run my air conditioner less. The prices and sizes vary quite a lot. How do I pick the best one for my home and will one really save much electricity?ANSWER: Running a whole-house fan will reduce your monthly electric bills during the summer. Even the most powerful models still use only a fraction of the electricity consumed by a typical central air conditioner.People are sometimes confused about what a whole-house fan actually is.It is a large exhaust fan that is usually mounted in the ceiling below the attic. It draws cool air in through windows and exhausts hot air into the attic. The cooling comfort comes from the hot indoor air being exchanged with cooler fresh outdoor air and the gentle breeze it creates indoors.An additional electricity-saving and comfort-improving benefit of running a whole-house fan is the attic stays cooler or cools down faster after being heated by the sun all day. With the attic and roof cooler, less heat is radiated down through the room ceilings into your family's living area.General fan sizing charts are available, but the proper size (cubic feet per minute of air flow) of a whole-house fan depends upon factors specific to your home and climate. It would be wise to install a two- or variable-speed fan as large as your budget will allow. Use high speed when you first start it to rapidly cool the house and then switch it to a lower speed.Another option is to install two smaller single-speed whole-house fans in different areas of the ceiling. This will allow you to have more control over the path of the air flow throughout your home for the optimum comfort and reduced noise levels.One the most efficient fan designs, but also one of the most expensive, uses insulating (R-22) reflective foam covers over the top of small dual fan blades or one larger blade ("Ghost" model).Small motors swing the covers up and open when the fan is running. When the fan is not running, the covers close to insulate, seal the opening and reflect heat.In general, more expensive fans will operate more quietly. They use internal rubber mounts and shrouds made of sound-absorbing material. The shrouds smooth the air flow and reduce resistance.When looking at fans, you will be able to identify the models with shrouds.Belt-drive models have the motor mounted off in one corner as opposed to less expensive direct-drive models with the motor over the center of the fan blade.By using a belt with a small pulley on the motor shaft, the blade will rotate slower. A highly pitched blade rotating slower can move more air with less noise.The following companies offer whole-house fans: Broan, (800) 558-1711, www.broan.com; Butler Engineering, (800) 433-1626, www.bvc.com; Nutone, (888) 336-3948, www.nutone.com; R.E. Williams, (888) 845-6597, www.wholehousefan.com; and Triangle Engineering, (800) 255-9014, www.trianglefans.com.Send inquiries to James Dulley, Butler Eagle, 6906 Royalgreen Dr., Cincinnati, OH 45244 or visit www.dulley.com.

QUESTION: We had an unusual hailstorm this spring and it damaged many fins in the air conditioner. One contractor said they could be straightened with a comb and another said they could not? Can they be fixed?ANSWER: To maintain the highest efficiency, fins must be straight for maximum air flow. Bent fins can be straightened again using a special fin comb with fine teeth spaced properly for your air conditioner design.When straightened, the metal in the fins will transfer as much heat as before they were bent. If many of them were bent so badly that they would break when you bend them back, then perhaps the parts need to be replaced.