HVI's Fresh Ideas Home Ventilation & Indoor Air Quality Guide Articles

Why Ventilation?

Homes today require specific strategies to maintain a healthy and comfortable living environment.

Ventilation reduces excess moisture and unhealthy indoor air pollutants. Properly designed and installed ventilation increases comfort and security.

Today's homes are more energy-efficient because they follow standards mandating better insulation and airtightness. However, without an appropriately designed, installed and maintained ventilation system, the benefits of these better-built homes can become liabilities.

When we think of buying, building or updating a home, we all too often focus on aesthetic features rather than factors such as the quality of the indoor air. In fact, according to the American Lung Association, 85 percent of Americans didn't realize the air in their homes posed a possible health hazard.

The good news, however, is that we are becoming increasingly aware of the importance of indoor air quality and its direct relationship to good health. We are demanding better comfort and healthier air. Mechanical ventilation is simply a system that moves stale, tired air out of the home, replacing it with an inflow of fresh air. A properly designed and installed home ventilating system provides a wide array of benefits not only to the homeowner, but also creates healthier, more comfortable and satisfied customers for mechanical installers and builders.

The Benefits of Good Ventilation

More than 40 million single-family homes have been constructed in North America since the late 1970s. Well-built, highly insulated and extremely airtight to reduce energy consumption, these homes also can experience higher rates of indoor air quality problems.

Common pollutants from materials, people, pets, activities and contents used to build and furnish the home, combined with excess moisture from poor ventilation, can create an unhealthy environment.

Excess moisture
Too much moisture can contribute to allergy problems and structural damage by encouraging the growth of mold, mildew, bacteria, dust mites, dry rot and insects. Showers, humidity, cooking and people produce large quantities of moisture on a daily basis.

Common household chemicals and pollutants

  • Cleaning supplies
  • Paints and solvents
  • Formaldehyde from furniture, carpet and building materials
  • Pesticides
  • Volatile organic compounds
  • Odors


  • Dust and dust mites
  • Pet dander
  • Pollen
  • Lead
  • Asbestos
  • Cooking by-products – grease and smoke

Tobacco smoke
A health risk to smokers and nonsmokers alike – children are especially at risk.

Combustion products
These are produced by fuel-burning heating equipment, gas water heaters, fireplaces, woodstoves, gas ranges and candles. They include but are not limited to:

  • Carbon monoxide
  • Carbon dioxide
  • Nitrous oxide compounds (NOx)
  • Soot
  • Unburned fuel
  • Moisture

Attics can overheat from long days of summer sunshine, and excess moisture can accumulate in the winter. Attic ventilation systems and components are designed to:

  • Remove excess heat to lower attic temperatures
  • Remove excess moisture to reduce relative humidity

Control of these factors through proper ventilation will enhance the comfort and indoor air quality of the home to help keep the occupants breathing safely. A quality ventilation system also contributes to preserving the structural integrity of the home, reducing maintenance costs and adding to the home's value. The strategies include:

  1. Intermittent local ventilation – For bathroom, kitchen and other moisture-, odor- and contaminant-producing areas.
  2. Continuous whole-house ventilation – To remove stale, polluted air and distribute fresh, outdoor air throughout the house.
  3. Attic and crawlspace ventilation – To protect attics and crawlspaces.

Home ventilation products are designed for easy installation and typically require little maintenance. Consumers should consult with their builder or HVAC contractor to determine the appropriate HVI-Certified products for their particular application. The contractor will ensure that products are properly installed and arrange for regularly scheduled system checkups to verify that the ventilation system is operating effectively.

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