How to Install a Wind-Driven or Power Ventilator

Have you ever been up in your attic on a sweltering day and noticed how much warmer your attic was as compared to the temeprature outside? This is because hot air becomes trapped inside your attic; thus making the temperature sixty degrees higher inside as opposed to outside. This, in turn, causes the air conditioner to work twice as hard. You can decrease the load and energy costs associated with your air conditioner with the right kind of ventilator. Here's how to install one.

Difficulty: Moderate

Instructions

Things You'll Need:

• Wind Driven or Power Ventilator; eight and one-half inch sheet metal screws; roofing nails, level, hammer, flashlight, garden hose

How to Install a Wind-Driven Ventilator

1. Purchase a wind-driven or power ventilator. The type of house you live in will determine the type of ventilator or fan you purchase, If your house has a roof with a conventional pitch, you have two options: you may purchase a fan that installs flush inside a gable; or one that mounts on the roof. However, if you have a "hip" roof and no gables, then you will need a fan or ventilator that is installed on the roof.

2. Fans designed to move hot air out of your attic are of different types. The one you choose is based on the amount of air you wish to expel from your attic and the energy-related costs in the area where you reside or live. There are fans driven by the wind; requiring no electricity, and fans requiring electrical power.
   
   The wind-driven ventilator seems to be a good choice in areas where energy conservation is a favorable practice: since the fan is powered by the wind it uses no electricity and, further in its favor, since the fan continually cools the attic, eliminating the "oven blast" of heat you experience upon entering your attic, it subsequently saves on your air conditioning use and associated costs. What could be better than a device that is able to reduce your air conditioning bill without incurring further electrical costs in order to do so?
   
   The wind-driven ventilator is turned by the slightest hint of a breeze; therefore, the attic air is continually "cooled" by use of the fan. Even when wind is absent outside, the wind-propelled ventilator will still remove heat from the attic. This is accomplished since air that is pulled in by attic vents will escape through the ventilator thus causing the ventilator to turn.

3. After considering all of the fundamental "good points" about the wind-driven ventilator, you will still need to consider whether the power-driven or electrical ventilator is possibly a better choice for you and your given situation. In other words, you may wish to make a side-by-side comparison and determine which ventilator is the "winner" as far as you are concerned.
   
   For one thing, power ventilators will provide a more efficient job of cooling than the wind-driven models.
   
   This is because power-driven models use electricity to move warm air out and cool air into the attic. Also, the power ventilator is thermostatically controlled, meaning when the temeprature reaches 110 degrees fahrenheit, the fan will run until temperature is reduced to 96 degrees fahrenheit.
   
   A cooler attic means the entirety of the house will be cooler, thus reducing air conditioning load up to possibly thirty percent.
   
   Not only will a power ventilator keep your house cooler, it also protects insulation and shingles from deterioration brought on by excessive heat and moisture.

4. In consideration of power ventilators, there are two types available. The more powerful fans are ideally suited and designed to be placed in the gable end of the house. (Remember, the use of this type of fan is dependent on the construction of your home.)
   
   The other type of power ventilator is circular in shape and is installed in the roof.
   
   The gable-type fans provide complete air change approximately every five minutes when placed in an approximate 8500 cubic foot attic. To install the gable-style fan see Step Five--otherwise, refer to Step 6.

5. In order to install the gable-type fan, you will need to cut an opening in the gable-end of your house. In order to do this, you will need to remove one of the existing studs; building in a frame of 2 x 4 studs and headers. (If you are not quite sure how to proceed at this point, consult a competent handyman, builder or carpenter for advice.) The frame should be lined and a casing built per the instructions supplied by the manufacturer.
   
   After you have completed this initial step, you will want to caulk the entirety of the opening in order to prevent air leaks. In addition, air intakes should be sufficient in number, most significantly around the eaves, in order that the fan doesn't "struggle" to keep air moving.

6. If you decide upon a roof-mounted version of the ventilator; you can depend on the fan cooling up to 2,000 square feet of living area.
   
   The 14 inch fan works most efficiently with, at minimum, 300 square inches of air intake located along (the area of) the eaves.
   
   The roof-mounted fan is enclosed in its own durable housing. The housing will never need painting and is far more durable than sheet metal. The ventilator's approximate dimensions are 27 1/2 inches square with a dome 8 1/2 inches in height. The fan is operated by a 110 hp (horse power), 115-v (volt) motor.

7. When mounting the roof-top model, the fan needs to be placed at the center (portion) of the roof and close to the ridgeline of the roof. See Tips.

8. Installation of the "power" ventilator is very similar to that of a wind-powered fan, if not almost identical. The very first thing you will need to do is locate the fan. This process or task should take place once you are inside the attic. In proceeding in this manner, you will be able to locate the unit between the rafters of the roof.

9. Drill a hole with an electric drill, once you have decided upon the best location for the fan.

10. Go outside and locate the spot where you have just drilled the hole. If you have trouble finding the location, have your spouse; family member of appropriate age or other adult shine a flashlight from inside the attic through the hole.

11. Using the hole as a point of reference, draw a twenty-seven and one-half inch square outline in the shingles. This may be accomplished by using a piece of chalk or a crayon: this outline will be used to install the unit's metal base.

12. At this point, you are ready to cut the opening. In order to begin, take a scrap of lumber and fashion a compass. Drive a nail through one end and drill a hole 17 3/8 inches away (taking a crayon for marking.) Place the nail in the hole found in the roof and very carefully scribe a circle on the shingle.

13. Next, you will want to cut through the shingles along the scribe line. This task can most generally be best accomplished using a sharp knife or tin shears. After you have done so, clear away the shingles found inside the circle and remove any extraneous items such as roofing nails.
    
    Adjust your "make shift" compass in order to draw a fifteen-inch hole in diameter and proceed to draw this second hole inside the area you just cleared. The fifteen-inch hole is cut through the roofing boards. Use either a keyhole saw or a sabre saw in order to cut the second hole. The best way to do this is to start in the center where the hole was drilled and work your way outward.

14. After completing cutting the second hole, you are now ready to install the ventilator. Accomplish this task by holding the unit parallel with the roof's ridgeline. Next slide the plastic flange up under the shingles starting this procedure at the center (portion) of the hole.

15. Position the ventilator unit squarely within the 27 1/8 inch outline you previously marked on the roof. Align it with the shingle lines.
    
    Continue sliding the flange underneath the shingles until the round housing is centered and placed properly in the hole. At this point, it may be advisable to go inside and verify that the unit is correctly in position.

16. Next, nail the exposed portion of the flange securely to the roof.
    
    The use of galvanized roofing nails is suggested in order to prevent rust.

17. You may check the unit for any leaks by way of a gardening hose. Because of the way the fan is positioned, there should be no leaks. However, if there is some leakage, caulk around the edges of the flange using butyl rubber caulking.

18. Electrical installation of Power Ventilator is the next step should you be installing the power ventilator. The control box of the unit needs to be screwed to a rafter in the attic. Upon connecting the 110-v line, follow wiring diagrams and instructions provided by the manufacturer.
    
    The wiring should meet the requirements of local building codes. If you have any questions whatsoever, consult an electrician.

19. Last, you must verify that the unit works properly. The following procedure is applicable for either roof or gable-mounted units.
    
    Place a sixty watt bulb inside a drop cord. Turn on the current to the fan on a cool day or on a day when the attic is cool. The fan, under such circumstances, should not start.
    
    Next bring the bulb near the thermostat located in the control box. The fan should begin operating. If the fan does not operate, carefully check all electircal connections. The fan, conversely, should shut off when the bulb is removed from the control box location.

20. To see a summary or less detailed description as to how to install a roof-mounted ventilator, see Section Two of this article.

How to Install a Roof-Mounted Ventilator

21. Following is a summarized rundown in the installation of the roof-mounted ventilator. Locate the ventilator from inside your attic; at least 24 inches below ridgeline on the rear or back side of your roof.

22. Center base over pilot hole (in roof). Use the inside of the base to scribe a hole in the shingles of the roof.

23. Using the circle as your guide, cut away the shingles with a sharp knife. It is advised to cut one-half inch outside of the circle.

24. Cut a hole through the boards of the roof using a sabre saw or by hand using a keyhole saw, following the circle as you cut.

25. Use a screwdriver to loosen the locking screw on an adjustable-pitch base in order that your may turn it properly.

26. Once loose, take a good hold of the top section and turn in such a way as to make the base level

27. Retighten the screw, slide the top-half portion of the flashing up under the shingles. Remove any nails that are in the way as you do so.

28. Now secure the base to the roof using eight roofing nails. Drive the nails through the flange. Next caulk the heads.

29. Place the ventilator over the "crumpled-looking" or "ribbed" portion of the base. Check ventilator installation by placing a level over the top of the ventilator.

30. Use the ring holes in the base as your guide when drilling: match holes around and through the flange.

31. Last, lock ring to flange by using 8 1/2 inch sheet metal screws. Drive screws in for secure and snug fit.

Tips & Warnings

• In regard to mounting the roof-top ventilator, the unit should be seen from only one side of the roof (preferably opposite street-side). In this way, your installation will appear neat looking. This may require that you move the ventilator down a bit, from the ridgeline, until it is not readily seen from the street.
• The most appropriate time to install any ventilation device is in the springtime. Do not try doing this in the summer months as it will be most uncomfortable working in the heat-drenched attic. By installing the ventilator prior to the summer months, you will be well on your way to reducing air conditioning load and associated costs as well as keeping your house cool and comfortable once the heat does escalate.
• Flushing excess heat away from your attic is best achieved when there is a sufficient number of air intakes along the eaves. With the fan positioned at the highest point in the attic and the intake vents located at the lowest point, even air flow is assured. Screen-backed vents (dimensions 8" x 16") make for an easy installation in the soffit of the roof. However, where the roof has no overhang, air intake must be provided by gable louvres. Ideally, through-the-wall intakes, should also be installed at the attic floor-line in the gables.