Wind Turbine/Roof Ventilators

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  #1  
Old 01-07-02, 01:37 PM
crawlfish2
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Wind Turbine/Roof Ventilators

My friends and I are debating the relative merits of covering turbine ventilators during the winter. Some argue that doing so will not conserve energy and contribute to a moisture problem while others think it does conserve energy and adequate ventilation in eaves and soffit are sufficient.

Could someone comment on this?
 
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  #2  
Old 01-07-02, 04:31 PM
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Provided you had adequate free venting, it wouldn't matter if your covered the turbine fan or not. The true value to the turbine fan or power ventilating fans is the lowering of the attic temperature in the summer, which prolongs the life of the roof. The secondary aspect is, if you have air conditioning, it will lower your cooling cost.
 
  #3  
Old 01-07-02, 10:25 PM
crawlfish2
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winterizing turbine

Thanks for your quick response!

If it pulls heat in the summer it will do that in the winter too, wouldn't it? Seems in winter there'd be some advantage to having it as warm in the attic as possible, or is this so nominal as to not make a difference?
 
  #4  
Old 01-08-02, 01:55 AM
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Wind turbines depend on the wind for it to work, where as free venting does not. The sole purpose for free venting is equilibrium relative humidity (ErH%) in the winter. Since insulation does not stop heat flow, it restricts it, there is a constance flow of heat into the attic. Cold air usually contains less humidity than warm air, which gives it the ability to absorb the heat and humidity in the warm air that manages to get through the insulation. Thereby prohibiting it's ability to condense. Free venting provides for a constant supply of low humidity cold air into the attic, where as a turbine would rely on the wind.

There are a lot of misconceptions about ventilation. The foremost is how it works in the winter. Most people think that warm air rises in the attic and goes out your gable or ridge vents and that causes cold air to be drawn in from the eaves or soffit vents. That is absolutely wrong. It maybe true in the summer but not in the winter. What determines air to rise is temperature. The higher the temperature the faster the air rises. The other factor is the volume of cold air in the attic verses the amount of warm air that manages to get through the insulation. There is ten time more volume per hour. What that means is as soon as the warm air got through the insulation, it would lose temperature rapidily and never be able to rise to the gable or ridge vents.

The way free venting actually works is cold air drops and it goes out the eave or soffit vents. Since the volume of air in the attic remains constant, the air leaving the attic through the eaves or soffit vents creates a siphon effect and that draws air into the attic through the gable or ridge vents. Thereby providing a constant supply of low humidity cold air.

The problem with ventilation is that it has different purposes for different seasons and different parts of the world. This is what makes ventilation a highly debatable subject and confusing.
 
  #5  
Old 05-21-08, 09:03 AM
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Turbine repair?

I have a nosiey turbine and was wondering if I can repair it (like change a bearing) or do I just replace it and can I just replace the part that is above the roof area. I don't want to get into the flashing or any roof leakage? They appear to be standard mechanical turbines no electric power.
 
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