Knowledge Base

Web Sites for Additional Information on Mechanical Ventilation

Environmental Protection Agency

1. EPA – EPA on Mechanical Fresh Air

The EPA believes that without mechanical ventilation to provide fresh air, moisture, odors, and other pollutants can build up inside a home. Mechanical ventilation systems circulate fresh air using ducts and fans, rather than relying on airflow through small holes or cracks in a home’s walls, roof, or windows. Homeowners can breathe easier knowing their home has good ventilation.

The Benefits of Mechanical Ventilation Are:
  • Better Indoor Air Quality. Indoor air can be many times more polluted that outdoor air.
  • More Control. Mechanical ventilation systems provide proper fresh air flow along with appropriate locations for intake and exhaust.
  • Improved Comfort. Mechanical ventilation systems allow a constant flow of outside air into the home and can also provide filtration, dehumidification, and conditioning of the incoming outside air.
How Ventilation Systems Work

A variety of mechanical ventilation systems are available to select from, based on local climate and the home’s heating and cooling system. In addition to one of the primary systems described below, “spot” ventilation fans should also be provided for kitchens and baths to remove the concentrated moisture and odors that can occur in these rooms. The typical systems and recommended climates are described below:

  • Supply Ventilation Systems—Hot or Mixed Climates. Fresh air is drawn in through an air “intake” vent and distributed to many rooms by a fan and duct system. The benefit of connecting to the return air duct is that outdoor air can be air conditioned or dehumidified before it is introduced into the home. Because supply systems continually introduce outdoor air, a home can become slightly pressurized. As a result, these systems are typically not appropriate for cold climates.
  • Exhaust Ventilation Systems—Cold Climates. Indoor air is continuously exhausted to the outdoors with one or more fans often located in bathrooms. Because indoor air is continually drawn out, the home become slightly depressurized.
  • Balanced Ventilation Systems—All Climates. With these systems, equal quantities of air are brought into and sent out of the home. This is usually achieved using two fans—one to bring fresh air in and another to send indoor air out.

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Energy Vanguard

2. Energy Vanguard

The whole-house ventilation is critical in an energy-efficient home to maintain adequate indoor air quality and comfort. Energy-efficient homes — both new and existing — require mechanical ventilation to maintain indoor air quality. There are four basic mechanical whole-house ventilation systems — exhaust, supply, balanced, and energy recovery.

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energy.gov

3. Department of Energy (DOE)

The Department of Energy manages the United States’ nuclear infrastructure and administers the country’s energy policy. The Department of Energy also funds scientific research in the field. The mission of the Energy Department is to ensure America’s security and prosperity by addressing its energy, environmental and nuclear challenges through transformative science and technology solutions. They also catalyze the timely, material, and efficient transformation of the nation’s energy system and secure U.S. leadership in clean energy technologies.

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Home Innovation Research Laboratory

4. Home Innovation Research Laboratory

A well-insulated, tightly-sealed building envelope (exterior walls, roof, and foundation systems) can prevent the escape of costly conditioned air, but may have unintended consequences for indoor air quality (IAQ). While drafty, uninsulated structures allow plenty of natural “infiltration”, well insulated and sealed structures may allow the buildup of contaminants such as bacteria, mold spores, cooking fumes, pollen and dust. In some climates, inside and outside humidity levels may cause mildew or excessive condensation problems.

There are a number of mechanical ventilation systems that give control of air-exchange to homeowners rather than to weather or wind speed, and that can be incorporated into new or existing homes. Decisions regarding the best ventilation strategy for a particular situation should always go hand-in-hand with consideration for energy efficiency. Whole house mechanical ventilation systems can increase energy efficiency by controlling the amount of fresh air that enters a home. This allows the house to have a tightly sealed building envelope while still allowing an adequate amount of fresh air to enter

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Berkeley Lab

5. Lawrence Berkeley National Laboratory

In the world of science, Lawrence Berkeley National Laboratory (Berkeley Lab) is synonymous with “excellence.” Thirteen Nobel prizes are associated with Berkeley Lab. Seventy Lab scientists are members of the National Academy of Sciences (NAS), one of the highest honors for a scientist in the United States. Thirteen of our scientists have won the National Medal of Science, our nation’s highest award for lifetime achievement in fields of scientific research. Eighteen of our engineers have been elected to the National Academy of Engineering, and three of our scientists have been elected into the Institute of Medicine. In addition, Berkeley Lab has trained thousands of university science and engineering students who are advancing technological innovations across the nation and around the world.

Berkeley Lab is a member of the national laboratory system supported by the U.S. Department of Energy through its Office of Science. It is managed by the University of California (UC) and is charged with conducting unclassified research across a wide range of scientific disciplines. Located on a 202-acre site in the hills above the UC Berkeley campus that offers spectacular views of the San Francisco Bay, Berkeley Lab employs approximately 3,232 scientists, engineers and support staff. The Lab’s operating costs for FY 2014 total $750.9 million. A study estimates the Laboratory’s overall economic impact through direct, indirect and induced spending on the nine counties that make up the San Francisco Bay Area to be nearly $700 million annually. The Lab was also responsible for creating 5,600 jobs locally and 12,000 nationally. The overall economic impact on the national economy is estimated at $1.6 billion a year. Technologies developed at Berkeley Lab have generated billions of dollars in revenues, and thousands of jobs. Savings as a result of Berkeley Lab developments in lighting and windows, and other energy-efficient technologies, have also been in the billions of dollars.

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Building Science Corporation

6. Building Science Corporation

Building Science Corporation provides objective, high-quality information about commercial and residential buildings. The resources available here combine building physics, systems design concepts, and an awareness of sustainability to promote the design and construction of buildings that are more durable, healthier, more sustainable and more economical than most buildings built today.

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Home Energy Magazine

7. Home Energy Magazine

Home Energy magazine’s mission is to disseminate objective and practical information on residential energy efficiency, performance, comfort, and affordability. It is the only magazine that thoroughly covers residential comfort issues from the only approach that really works, systems engineering. Most of Home Energy’s editorial content comes directly from the people researching and employing innovative design, building, and remodeling practices and products. They are the experts using the latest and best building techniques, with an emphasis on implementing sound building fundamentals and curing sick buildings. The organization remains a nonprofit company devoted to getting information out to the public.

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Ashrae

8. ASHRAE Standard 55

ASHRAE standard for recommended comfort

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