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Transcript
Jim Hardwick:
The air has to speed up and travel to the other side. When air is moving fast, it has a decrease in pressure.
Hi, I am Jim Hardwick with Ideal Roofing, and you need attic ventilation. It’s going to move the air out of your attic, obviously to keep it cooler, and also the moisture. Let’s take a look.
Today ,we’re just using an example of an average attic square foot of 2000 square feet. Now, this is of your attic space, not your house, so let’s take a look at the differences. If you have an attic floor with a low sloped roof, here’s the air space that you’re ventilating. Let’s say the same attic floor with a steep roof, the air that you need to ventilate is greater. So we’re going to take a look at the two types of ventilation products. I’ve divided them into two parts. Right here, we have your active ventilation. In here, we have your passive ventilation.
Okay, before we discuss the different types of ventilation, we first have to address soffit or intake. This house has louvered soffit vents located around here at the soffit, and you need plenty of these intake for the whole system to work. It’s just like a straw. If there’s one end that’s closed and the other end, the straw doesn’t work, so you have to feed the system from down here at the soffit to get plenty of airflow up and through the soffit so that it feeds those different types of ventilators on the roof.
Here are examples of active ventilation. Here is a 12-inch turbine. The way it works, it spins. Look how little effort it takes to make it spin, and these should always be spinning. Some people say, “Oh, it’s only going to spin if it’s windy.” No, just the convection of the air, the hot air in the attic coming up will give it the slightest spin. If you notice on the bottom, it has a large opening and you can see the blades are turning, and it’s pulling air out just like the back of a fan would.
The next product is going to be a solar-powered vent. If you look at the bottom, obviously it’s a solar-powered fan, and these are very powerful. This is pulling up a lot more air, just because of the fan power that it’s sucking out of your air.
This is ridge vent, probably the most overused piece of ventilation here. The way this works, and it is active, believe it or not, even though it doesn’t have a fan or a blade, but the way it works is these baffles right here, as air is moving up your roof line, it hits the baffle and it has to go over, so therefore the air has to speed up and travel to the other side. When air is moving fast, it has a decrease in pressure. The stagnant air in your attic is higher pressure, so therefore it creates a little bit of a draw. But it’s so slight, even though it’s active, you have to use a lot of it to equate to these other products, and that’s why it’s overused. You’ve got to have enough ridge to be able to use this product.
Here are some examples of passive ventilation. This is known as a static vent. Other areas of the country might have different slang terms as turtle vents, but it’s a static vent. It’s passive. Why is it passive? Notice when I turn it upside down, there is no electric fan, so it’s just a large opening with a dome on the top so it doesn’t leak. So it’s not drawing air, it’s just working on the hot air escaping the house, and so that’s why it’s passive. This is known as an Airhawk. Same thing, little bit of a smaller opening, there’s no fan, there’s nothing drawing up the air, and it just has louvers on the side for the hot air to escape, but again, these are both passive ventilation examples.
Okay. Now, we’re back to our 2000 square foot of attic space. We’re going to take a look at the different products After we just saw how they performed. We have it divided into active and passive, remember? So on that same attic space, a turbine would take at least three. The ridge vent would be 44 feet. The solar vent would be one to two, depending on the rating. So now let’s move to the passive. Passive would be Airhawks, 10, which if you remember, those small squares, and the static vent is eight because the opening was larger.
So make sure you can’t just punch holes in your roof and expect to solve your problems and start mixing and matching ventilation. You need to have a qualified, educated roofer about ventilation before you call. Also, if you didn’t notice, Ridge vent, 44 feet. What does that mean? Not every house can even use ridge vent. You can use any one of these other products on every house, but because of that requirement and the performance, not every house can take ridge vent.
