Whole House Exhausting and Ventilating

There are more advantages of home exhausting and ventilation than just for reducing room temperature. The air within homes can become hot and stale from moisture, odors, and pollutants that penetrate the home or are generated internally by human activity and out gassing from building materials and furnishings. A constant supply of fresh, outdoor air can provide greater assurance of good indoor air quality and improved comfort.

In most homes, ventilation is provided accidentally when air leaks through the building envelope. Accidental ventilation is unreliable because it is dependent on a pressure difference between indoor and outdoor spaces caused by temperature or wind variations. Too much fresh air often enters a house during cold weather causing uncomfortable drafts and high heating bills. Not enough fresh air may enter during mild weather which can lead to poor indoor air quality.

Air leakage through the building envelope accounts for between 25 percent and 40 percent of the energy used for heating and cooling in a typical residence. Many new homes are being air sealed to reduce this energy use. Where tighter construction reduces air leakage and accidental ventilation, active ventilation systems may be needed to provide fresh air.

The advantages of exhaust ventilation are control and consistency. Moisture, odors, and pollutants are removed continuously, regardless of weather conditions. High indoor air quality is maintained due to the constant infiltration of outdoor air.
Exhaust ventilation systems are most suitable for moderate climates. Care must be taken during design and installation to prevent these systems from “back drafting” dangerous combustion gases from fireplaces and gas appliances into homes.

BENEFITS
Exhaust ventilation systems can provide many benefits including:

Improved indoor air quality.

Exhaust ventilation systems continuously remove moisture, odors, and pollutants. This proactive approach to ventilation can result in improved indoor air quality.

Improved health:

Stale air can cause health problems. It can be responsible for symptoms such as headaches, drowsiness, and respiratory problems. These symptoms are more common in homes with poor ventilation and moisture control. Continuously providing fresh air can result in the improved health and well-being of the occupants.

Lower utility bills.

Less energy is consumed to operate ventilation systems than to heat and cool excessive amounts of outdoor air that infiltrates leaky homes. This can result in lower utility bills, making homes less expensive to operate.

Proper Attic Ventilation Is Important:

Poor Attic Ventilation Can Ruin Your Insulation, Destroy Your Shingles, And Raise Your Energy Bills!

Why Take Risks?

It is estimated that 9 out of 10 homes in North America do not have proper attic ventilation. Why? Because most people are unaware that attic ventilation can impact the longevity of their entire home! For example, during summer months, an improperly ventilated attic can cause heat to build in excess of 160°F. This superheated air eventually penetrates the ceiling insulation into the living area below.

Types of damage that can result include:

• Premature aging of your roofing system ("fried" shingles)
• Warping, cracking, or breaking down of wood framing
• Damage to siding, exterior or interior paint, and wallpaper
• Higher energy costs

A properly ventilated attic can help reduce the load on your air conditioner by moving the superheated air out of your attic before it builds up and causes damage.

During winter months, various household appliances, bathtubs, showers, and cooking vapors can contribute to excess moisture build-up. Improperly ventilated attics will allow this moisture to collect and cling to the underside of the roof. There, it will condense and fall, soaking the attic insulation and reducing its efficiency.

Additional structural damage can include:

• Roof deck warping and rotting of the wood frame
• Mildew growth
• Buckling of shingles and felt

Finally, attics should be properly ventilated to help prevent ice dams in cold northern climates. During the winter, ice and snow on a roof will melt and run down the deck to the cooler eaves. This run-off can re-freeze; creating an ice dam that will trap moisture on the roof. The moisture can eventually back up under the shingles and enter your home - causing hundreds or thousands of dollars of damage to your ceilings and walls. Adequate attic ventilation will reduce the amount of initial melting that occurs on your roof, thereby reducing the chance that ice dams will form.

Proper Attic Ventilation

Proper attic ventilation systems allow a continuous flow of outside air through the attic protecting the efficiency of the insulation and helping to lower temperatures in the living space.

It consists of a balance between air intake (at your eaves or soffits) and air exhaust (at or near your roof ridge). The FHA (Federal Housing Administration) recommends a minimum of at least 1 square foot of attic ventilation (both intake and exhaust) for every 300 square feet of attic space. For example, if your attic is 900 square feet, you need a total of 3 square feet of ventilation. This amount is generally divided equally between intake and exhaust ventilation (i.e., 11/2 feet of each), to insure proper air flow through the attic.