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The concepts for "green" building are not new trends. The energy crisis of the early 1970s created many initiatives to improve home building practices and led to the development of a wide variety of new and improved products. It was recognized that poor insulation, air leakage and inefficient windows were responsible for most of the energy being consumed by a typical home. Over the last three decades, building science research has refined our knowledge, and manufacturers have continuously improved products, pushing green building into the mainstream where its impact can truly make a difference.
A tighter, well-insulated home saves energy, increases comfort for its occupants and creates an opportunity to manage indoor air quality (IAQ) effectively through the careful selection of materials and the proper use of mechanical ventilation. The wide variety of ventilation products available on the market today makes it possible to control airflow in every area of every home. Whether the need is to exhaust moisture from bathrooms, cooking odors from kitchens or improve overall air quality throughout the entire dwelling, quiet, energy-efficient solutions are readily available.
Houses Are Systems
A house is a system integrating the building envelope, windows, heating and cooling systems, ventilation and, most importantly, the occupants. Understanding that all the components must work together is key to successful green buildings. So important is the need for proper ventilation that all green building programs require mechanical ventilation individually designed for each house.
Bathrooms
Bathrooms in green homes must have mechanical ventilation to remove excess humidity and odors. Check for ventilation rate requirements with local authorities and specific green building programs. There are many HVI-Certified product options that can be used to meet these varied requirements.
Surface-mounted fans - Traditional surface-mounted fans are available in wide ranges of prices and performance levels. It is possible to select products today that are almost silent, use very little energy and still provide powerful ventilation. Fans approved for installation in showers and steam rooms serve to exhaust moisture very effectively. Humidity-based controls can provide automatic operation, and timers ensure that ventilation continues long enough to reduce moisture levels.
Inline fans - Inline fans are typically installed remotely, often in attics and basements, which helps keep any noise from the fan's operation at a minimum in the occupied areas of a home. One fan can be used to ventilate two or more bathrooms through a common exterior exhaust hood. A variety of exhaust grilles are available, some with lights incorporated. Inline fans are a good choice when the duct runs to the outside of the home are long, as they are better able to maintain airflow.
Integrated controls - Integrated controls for exhaust fans have recently been introduced that allow several separate fans to operate as a system to meet both intermittent and continuous ventilation requirements. These "smart" systems sense the need for ventilation and can be programmed to fit the house in which they are installed to optimize air exchange while minimizing energy loss.
Heat and energy recovery ventilators - Heat and energy recovery ventilators (HRVs/ERVs) can also provide ventilation for bathrooms. Transfer of energy from one air stream to the other allows HRVs and ERVs to minimize energy consumption while providing quiet ventilation through ductwork connected to bathrooms and kitchens. Controls installed in a bathroom allow the continuous ventilation rate to be increased when needed to remove excess moisture and odors. The combination of continuous and intermittent ventilation ensures that bathrooms remain dry and fresh.
Kitchens
All kitchens produce moisture, odors and smoke, making good ventilation essential in every home. Although the intermittent ventilation needs associated with cooking are the most obvious, kitchens also need continuous ventilation to maintain indoor air quality at all times.
Range hoods - A kitchen range hood is a fan with an enclosure designed to capture and exhaust the heat, odors, gases, grease, steam and smoke produced by cooking. A range hood's fan effectively captures the rising column of air directly over the cooking surface and then exhausts the contaminants outside the home.
Recently, HVI-Certified range hoods bearing the ENERGY STAR label were introduced into the marketplace. The ENERGY STAR label indicates that products meet strict energy efficiency guidelines set by the U.S. Environmental Protection Agency (EPA) and the Department of Energy (DOE). ENERGY STAR-qualified ventilation products that include lighting use 70 percent less energy, on average, than standard models equipped with halogen lights.
Bedrooms
We spend six to ten hours of each day in our bedrooms - they need fresh air, and opening windows is not always the best option. Distribution of fresh air to bedrooms is a requirement of most green housing programs and can be accomplished with exhaust and supply fans, heat and energy recovery ventilators, or distribution through the forced-air heating system.
Other rooms
Other rooms of the house may require local ventilation to address periodic high levels of contaminants resulting from various hobbies or temporarily increased level of activity of the home's occupants. Local ventilation exhausts pollutants before they spread throughout the home, which is important to any homeowner who wants control over indoor air quality.
Garage
Attached garages are obvious sources of pollution - from unhealthy odors from cars, garden chemicals and other stored items to deadly carbon monoxide. In today's advanced green homes, the shared walls between the living area and garage are carefully sealed to minimize the entry of contaminants through infiltration. However, when the entry door between the garage and house is open, there is a risk that contaminants may enter. An exhaust fan activated by garage door activity will help ensure that the extra load of pollutants generated when a car enters or leaves does not enter the home. Air should continue to be exhausted for at least 20 minutes after a car has entered or left the garage to ensure that exhaust fumes are sufficiently diluted. Any combustion heating systems that are not completely sealed need to be supplied with make-up air to ensure safe operation.
Why Build Green Homes?
There are clearly significant benefits to applying proven mechanical ventilation techniques when building new or renovating homes to green building standards:
- Reduced operating cost for the entire lifespan of the home, which is often much longer than anticipated.
- Increased comfort and control of the indoor air, allowing occupants to lower the risk of certain illnesses and maintain improved overall health.
- Reduced maintenance and repair as a result of tight construction on the inside and exteriors that are designed to stay dry.
- Increased resale value as a result of all the above benefits.
Ventilation is a critical component of green homes, and today the HVI-Certified product choices to meet the requirements of advanced building programs and satisfy customers have never been better.
Excerpted by permission of The Home Ventilating Institute (HVI) from Fresh Ideas - The Guide to Home Ventilation and Indoor Air Quality.
The Healthy House Institute (HHI), a for-profit educational LLC, provides the information on HealthyHouseInstitute.com as a free service to the public. The intent is to disseminate accurate, verified and science-based information on creating healthy home environments.
While an effort is made to ensure the quality of the content and credibility of sources listed on this site, HHI provides no warranty - expressed or implied - and assumes no legal liability for the accuracy, completeness, or usefulness of any information, product or process disclosed on or in conjunction with the site. The views and opinions of the authors or originators expressed herein do not necessarily state or reflect those of HHI: its principals, executives, Board members, advisors or affiliates.
