EQUIPMENT FOR COOLING

YOUR HOME

It has been a hot, summer day, be several degrees cooler than outand since early afternoon the in- side, but it can seem warmer if the side of your house has been hot. Now air doesn't move. Also, air movethe sun has gone down, and outside ment increases moisture evaporathe temperature has dropped a little. tion, and moisture evaporation Inside, though, your house remains cools the body, or skin surfaces. just as hot as it was—hotter now A good room fan has large blades, than outside.

turns at about 1,000 r.p.m. (it may You open windows, but that have a speed adjustment), operates doesn't help much because the air quietly, and has an oscillating mechis calm and there is practically no anism. It will cost from about $20 circulation, no exchange of inside for a small table model to $60 for a air for outside air.

7-foot pedestal floor model. (Price If you had some type of air cool- ranges given in this bulletin are ing, you think, it would be better. based on typical 1969 retail prices.) And you decide to do something Attic and window fans exchange about that. You decide to cool your inside air for outside air. You can home mechanically—so it will stay use them for night cooling, or comfortable during the day and be whenever the temperature inside cool at night.

your home is greater than the temThere are four ways, you learn, perature outside. A time switch can to cool your home:

be installed in the electrical circuit . With fans.

to your fan to cut it off automati• With an evaporative cooler cally at any time you desire. When (cooling with water).

you have cooled your house at night, • With an air conditioner.

keep the windows and doors closed . With a heat pump.

during the next day as long as it is Which way you choose will de- cooler inside than out. pend on how much you are willing

You will find that window fans to invest, both initially and in are easier to install than attic fansoperating expenses, and on the climate of your community.

Cool With Fans

You can buy two types of cooling fans:

• Room fans.
• Attic and window fans.

Room fans stir up the air. The temperature inside your house can

no construction is required—but you the rooms by the width. Then mulwill also find that they are usually tiply that by the height. noisier.

• If you live in the dotted area of Fans are rated by the amount of the map (fig. 1), divide the volume air they move in cubic feet per by 1.5. This will give you a miniminute (c.f.m.). Fans rated by an mum c.f.m. requirement. If you live Association are more likely to de- in the undotted area, your minimum liver approximately the quantities c.f.m. requirement will be the same of air stated.

as the volume you want cooled. For best results, you will need • Pick a fan that has a c.f.m. ratthe help of an engineer in determin- ing larger than your c.f.m. requireing the size of attic or window fan ment-a larger rating will allow for needed for your house (some retail slight differences in test procedure firms provide the services of a and efficiency. trained technician). The air inlets If you choose a fan that is driven and outlets, the horsepower of the with pulleys and a belt, rather than fan motor, and the revolutions per one that is driven directly by the minute of the fan blade all should motor, the size of the pulleys can be be taken into consideration. How- varied slightly to adjust the amount ever, you can determine the approxi- of air moved. Models with two-and mate size yourself and probably get three-speed motors are also availsatisfactory results.

able. To determine the size fan you will Normally, a 13-horsepower, 36need

inch attic fan will provide 10 air • Find the volume of the area you changes per hour for the average :3want to cool. Multiply the length of bedroom house. This is sufficient

Figure 1.—Minimum air changes recommended for fan cooling.

3

$25 up.

ventilation in the dotted area. Such a fan will cost about $100.

House Design A larger attic fan is required in the undotted area-a 13- or 1/2

Good design and construction are horsepower, 42-inch fan that will as necessary to keeping your house normally provide 60 air changes per cool in the summer as they are to hour for the average 3-bedroom keeping it warm in the winter. The house. It will cost about $120.

house should be tightly constructed Window fans are usually smaller.

and well insulated. In the summer, They range in size from 20 to 30 the windows should be shaded from inches. The 20-inch size is the most

the direct rays of the sun. popular. It will generally provide A more comprehensive discussion about 15 to 20 air changes per hour of house design, insulation, and for the average 3-bedroom house. cooling equipment appears in Twenty-inch window fans cost from

USDA Agriculture Handbook 241,

“Farmhouse Design and Equipment When cooling with a fan, you

for Summer Comfort.” This pubshould close off any portion of the lication is available from the Superhouse that you do not wish to cool;

intendent of Documents, U.S. otherwise, the fan will not provide Government Printing Office, Washthe proper number of air changes ington, D.C. 20402, at 15 cents per per unit time.

copy. You can also remove accumulated attic heat during the day with an attic fan. Often an attic is 25° or Cooling with fans has some dismore hotter than outside; even if the advantages. Dust and pollen are ceiling of your house is insulated, likely to be drawn into your home. this additional heat will warm your Fans are noisy. The cost of a good house.

attic fan plus installation may be When you remove attic heat with as much as a room air conditioner. an attic fan during the day, close the While the attic fan may cool the attic off from the rest of your house. entire house in some areas at night, Otherwise the fan will draw hot, it may not help much during the day outside air into your house.

because of high outside air temperSuppose you decide to cool your atures. And remember, a fan will home with an evaporative cooler cool your house to only approxi(cooling with water) or air condi- mately the temperature of the outtioning, but wish to ventilate the side air. On the other hand, the room attic anyway. A fan-smaller than air conditioner will usually cool the usual size attic fan—will do only one or two rooms, but it will that; it should be capable of chang- cool both day and night. ing the air in the attic at least once per minute, and should operate con- Cool With Water tinuously when the temperature in the attic exceeds 110°. It may be con

In Dry Climates trolled by thermostat, time clock, or You will find that the most commanual switch. Such a fan with mon and effective method of cooling thermostat and automatic gable with water is the water-evaporation shutter will cost about $60.