Attic ventilation: A guide to attic ventilation options, costs, and installation

Proper attic ventilation is an important part of a healthy home. The flow of air through the attic space helps regulate the temperature in the house and reduces humidity, which can lead to mold, damaged shingles, and ice dams. However, before delving into the types of roof vents and their costs, you should understand how proper attic ventilation works.

The attic requires a balanced ventilation system, with as much air entering through the inlet openings as it exits through the outlet openings. Ideally, the inlet openings are installed along the roof edges at the lowest point in the attic in the soffits. The exhaust vents are installed along the ridge, the highest point in the attic. This creates a natural stacking effect, or continuous cycle, in which the warm, humid air draws cooler, drier air behind it as it rises.

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In the heat of summer, this exchange cools the attic, which contributes to a cooler living space and lower energy costs. In winter, when the outside temperature is colder than the temperature in the attic, moisture builds up. In a well-ventilated attic, however, moisture escapes with the warmer air as it draws in the colder outside air. And with adequate attic insulation, the cold has little effect on the living space below.

“The goals are to keep the air moving,” says Keith Gregory, vice president of the residential division for Baker Roofing Company in Raleigh, North Carolina, “and the attic at or near outside temperature, not cooler.”

How to determine if your attic is properly ventilated

Fortunately, your home will tell you if the attic lacks a balanced ventilation system. Some signs are:

  • Overly warm living areas caused by the heat and lacking space.
  • Moisture or frost in your attic in winter.
  • In winter, ice dams form on the edge of your roof.
  • The lack of vents in your eaves or outlets on your roof.
  • Rotting or rotting exterior.
  • Peeling paint.
  • Roof damage.

Roof ventilation options

According to Gregory, there are two types of attic exhaust vents – static and powered. A static vent is basically a strategically placed hole to allow warm air to escape. they include Ridge ventsthat run in a box shape along the length of the roof ridge Cape winds, or Turbine vents. A powered vent contains a fan.

The inlet openings include those in the soffits and those in the gables. Gable openings can function as both an inlet and an outlet, depending on the wind direction and speed. However, since they are in the highest part of the house, they are best used as an exhaust vent.

Types of attic ventilation: advantages and disadvantages

Each type of attic ventilation has advantages and disadvantages. Here we split them up so you can choose the best option for your home.

Ridge vents

According to home service company HomeAdvisor, ridge vents cost $ 2-3 per linear foot, without installation. The vents come in 4 foot sections that are sold individually or in the case of 10. On average, adding a ridge vent to your home will cost you around $ 400 to $ 500 total.

advantages

  • They fit into your clapboard almost invisibly
  • Aesthetically pleasing
  • Provide ventilation without electricity or wind
  • Most effective passive vent that rarely leaks

disadvantage

  • Works best with reveal openings
  • Easier to install when the house is re-roofed
  • Adjusting shingles for a retrofit can be tricky
  • Must close for other types of ventilation and install an adequate suction opening

Static vents

static roof ventilation on a house

(Photo credit: Home Depot / Master Flow)

Other unpowered vents come in many shapes, colors, and styles, ranging from $ 10 to $ 400, according to HomeAdvisor. Static vents are also known as box vents and have no moving parts to direct airflow. The types of static vents include the mushroom, turtle, and dormer vent, which refer to their shapes.

advantages

  • Easier to add to an existing roof
  • Can be installed anywhere on the roof
  • There are no moving parts

disadvantage

  • Need to install multiple
  • Not as attractive as a ridge vent
  • Some styles become homes for birds
  • Need frequent inspections

Turbine vents

Although technically static venting, turbines are in a class of their own because the wind provides their power. Turbine vents cost anywhere from $ 20 to $ 100 plus an hour or two of manpower, according to HomeAdvisor. The wide range of costs depends on the quality. Experts recommend paying for the higher quality ones from the start. How many you will need depends on the size of your roof.

advantages

  • Work harder when the wind blows
  • They require fewer turbine vents than other static vents

disadvantage

  • Steel can rust
  • May make noise or stop working over time
  • Some consider them unsightly

Powered vents

Aptly named because they need solar or electricity to turn a fan that moves the air. According to HomeAdvisor, an electrically powered vent costs $ 100 to $ 400 and a solar powered vent costs $ 200 to $ 500, with an installation ranging from $ 135 to $ 300 per vent.

advantages

  • More expensive models may include thermostats and hydrostats that you can set to a specific temperature or humidity
  • Move more air out of the attic than through a static vent
  • Can be mounted on the roof or in the gable

disadvantage

  • Can draw more cool air from air leaks in the attic than from the reveal openings
  • Increases your cooling costs
  • Must have suitable intake openings, otherwise the engine can wear out prematurely
  • Require periodic inspections to ensure they are being carried out properly
  • Wiring required which can add to the cost of hiring an electrician

Roof inlets: advantages and disadvantages

There are two main types of inlet ports. The style of your home and budget will help you make the right choice for you.

Reveal openings

Soffit ventilation under the roof - attic ventilation

(Image credit: Lowe’s / Air Vents)

Perforated soffit sections every few feet or the entire length of the eaves form your soffit openings. The sections are $ 3.30 to $ 4.50 per linear foot, according to HomeAdvisor, and the full length vents are $ 8 to $ 10 per linear foot. Unless you replace your entire soffit, expect to pay a contractor $ 45 to $ 75 an hour for the work.

advantages

  • The reveal openings are in the lowest part of the roof and allow cooler air to enter the attic
  • Soffit openings run the length of the house and allow more air to circulate than gable openings that are only at the ends of the attic.

disadvantage

  • Most effective when used with a ridge vent
  • Homeowners tend to cover them with insulation that blocks airflow

Gable slots

You will find gable openings at the top of the roof gable. They can be as inconspicuous as a perforated piece of vinyl siding. Or if your gable end faces the street, you can go for something more decorative. Gable openings range from $ 10 to $ 60, according to HomeAdvisor, with some models being just as expensive at $ 100.

advantages

  • Can serve as both an inlet and an outlet port.
  • The cheapest option
  • Can be used with a roof fan

disadvantage

  • Cannot be used with some roof lines
  • The least effective method of cooling the attic when used on its own

Other things to consider

First of all, be careful not to block any attic ventilation. When insulating an attic, homeowners can accidentally cover soffit openings, rendering them unusable. Keep all insulation away from the eaves or install baffles between the rafters to direct air from the vent up along the roof deck.

If you’re using your attic for storage, don’t overfill it, warns Gregory. “When the attic is too full,” he says, “it stifles the flow of air and causes moisture to build up.”

Gregory also suggests selecting a contractor with a proven track record and experience in making decisions specific to the region. “You want someone who understands and knows what he’s seeing,” he says.

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