Attic Fans Can Bring Relief from Portland’s Heat in the Summer

Even in a moderate climate like Portland, summer temperatures can make some houses miserable to stay in. In certain situations, attic fans can help greatly solve that issue.

Solar Roof Fan compressed

A properly vented attic, with a balance of functional intake and passive exhaust vents (or ridge venting) should typically be adequate to ventilate your attic. However, with the multitude of home designs present, there is no shortage of unique situations that will benefit from an attic fan to help increase the proper airflow. When airflow in an attic space is restricted, numerous problems can occur, including mold, higher heating and cooling cost, and possibly worst of all, lots of discomfort during the hot months during Portland’s summer.

Passive Intake and Exhaust Vents

First, let’s first describe what passive ventilation is. In a nutshell, this refers to non-mechanical means of allowing air to pass through an attic. Properly designed and installed vents allow air movement while still keeping the roof system and eaves watertight. While there are various styles of passive exhaust vents, they work with physics and as the hot air in your attic naturally rises, they provide an always present outlet.

Often overlooked are the intake vents. They might be overlooked both by not being present at all (many older homes have none) or by existing but by being blocked by excessive insulation. All the exhaust venting in the world, whether passive or via attic fan, will do little good if there is not direct, exterior intake vents either in the eaves and soffits (most common) or possible on the gable end of the house, down at floor level. As odd as it might seem, the use of an attic fan without proper intake venting can often make the problem worse. Instead of pulling in air from outside, it might suck up air-conditioned air from within the living areas, further increasing cooling costs.

The key to a properly ventilated attic is when the temperatures in the attic are not too different from the outside temperature. This will help result in a cooler home during the high heat.

Common Applications for Attic Fans

So, to the item at hand – attic vents. As mentioned above, there are many situations when passive ventilation can not maintain adequate airflow. Also stated above, no amount of exhaust will help if there is no source of fresh air to pull through the fan or vent, so don’t expect an attic fan to help without the other side of the equation.

Common situations that benefit are when there are unusual home designs, often the result of additions put onto homes. Many times these additions either have separate attics or can not avail themselves to the main stream of ventilation passing through a main attic. This specific situation is more common on older homes. The result can be pocketed sections over living spaces that cannot vent the rising air and moisture from those spaces.

Yet we have also seen many newer houses that due to unique architectural designs, have several disconnected attic spaces which can not obtain either direct intake or direct exhaust venting. This can be quite problematic since the living spaces below such attics continue to create moisture and humidity that travels upward into these areas. Overheated attics are a frequent cause of premature roof failure. Inversely, poorly ventilated attics are the primary cause of leaks from ice dams during extreme cold weather. It can be quite frustrating to have a newer home that one assumes was built using the best current practices of construction, experience a fundamental ventilation problem.

Benefits of Attic Fans

The primary benefit of attic fans is that they can help create the much needed air-movement in an otherwise stagnant section of attic. In extreme cases, holes may need to be cut between attic sections or ventilation piping used to connect the stagnant area to a source if incoming air so that the attic fan’s effort can be balanced with intake ventilation. There are situations where the only feasible solution to venting a space is with an attic fan.

That being said, one never wants to assume that where passive vents can handle the job, the installation of attic fans will simply improve the situation. Balance between intake and exhaust venting is important and more cannot always be simply assumed to be better. If a space is designed to work with passive ventilation but there just is not enough flow, the first thought should always be to see if supplemental intake or passive exhaust venting with bring it into proper balance.

Regarding what type of attic fans work best, there is so absolute answer. We personally tend to like solar attic fans because no wiring is required, thus helping keep costs lower as the result of not having to hire an electrician. Don’t worry that the Portland area isn’t sunny enough – solar devices work quite will even on days with very limited direct sunshine.

If you have doubts about the effectiveness of your attics ventilation, give us a call for a free inspection.