Proper ventilation helps improve indoor air quality. Ventilation can control indoor humidity and airborne contaminants, both of which either contribute to or act as health hazards. The American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE) and several states (Minnesota, Washington, and Vermont) have ventilation standards designed to ensure acceptable indoor air quality.

High indoor humidity can spur mold growth. High humidity may result from poor construction/rehabilitation, site design that does not properly manage water, and/or inadequate air exchange. A reasonable target for relative humidity is 30-60 percent. A low cost hygrometer, available at hardware stores, can be used to measure relative humidity. In cool climates, inadequate ventilation in the winter can contribute to excessive moisture and humidity because normal activities create moisture (cooking, bathing, breathing), and there is insufficient natural ventilation (opening windows) or mechanical ventilation (fans, exhaust systems) to remove the moisture. In warmer climates, the heating, ventilation, and air conditioning (HVAC) system can pull warmer, humid air inside. In this case, the ventilation system may help create indoor humidity problems unless the system also dehumidifies the air. Common sources of airborne contaminants include:

Indoor contaminants: These include chemicals used in the construction or renovation of buildings (e.g., glues, off-gassing from carpets, emissions from particle board, cleaning compounds). In addition, appliances that burn gas can produce particulates and carbon monoxide. Incomplete combustion and poor ventilation of these appliances (cook stoves, gas furnaces, gas boilers, and gas water heaters) can contribute to indoor contaminants. Gas cook tops should be used with fans that send exhaust outside. Gas-fired heating appliances should be sealed and power-vented systems installed to remove products of incomplete combustion. Wood-burning stoves can also create particulates and must be vented outside.

Outdoor contaminants: Outdoor particulates can be drawn inside when the heating or cooling system draws air into a home. Particulates and allergens found in outdoor air can be asthma triggers. Filtering incoming air for HVAC systems effectively filters particulates. Experts recommend using filters with a MERV 6-8, but higher MERV levels trap smaller particles and generally are more appropriate for those with allergies or where the indoor environment has a high concentration of mold spores, dust particles, or other allergens.

Two types of ventilation can help control harmful air contaminants and humidity: spot ventilation and dilution ventilation. Spot ventilation draws air from a particular location (e.g., bathroom, kitchen) and exhausts it to the outside. Dilution ventilation address low-level contamination throughout the home.

Spot Ventilation: Exterior exhaust fans should be installed in all bathrooms and kitchens. These fans remove humidity and carbon monoxide. The most effective fans are quiet and durable. Use fans that operate at one sone or less and exhaust to the outdoors. Fans equipped with timers or de-humidistat controls are useful to ensure the fans run for a sufficient period of time. A good rule of thumb is to run a bathroom fan for about 45 minutes after a shower.

Dilution Ventilation: Dilution ventilation addresses the entire living space. Air changes (exchanging indoor air with outdoor air) and air cleaning help determine the effectiveness of dilution. Air changes result from a combination of natural ventilation (infiltration; leakage; windows) and mechanical (controlled) ventilation. Air cleaning occurs when particulates are filtered and when air is dehumidified to remove moisture. The goal is to provide sufficient changes to ensure a healthy environment. There are several types of heating and cooling systems with filtration that can be installed to accomplish this. A common element necessary in all systems is duct sealing, particularly on the return side (side drawing in the air). The Air Conditioning Contractors Association (ACCA) provides guidance on duct sealing in its Manual D: Duct Design.

Source: Alliance for Healthy Homes 

Following these concepts, here are some fresh news about ventilating products:

New Retrofit Ultra Silent™ Series Fan

Broan-NuTone®, the leader in residential ventilation, has made it much easier and less expensive for homeowners to replace their existing bath fan with a much quieter, energy-efficient solution. More... 

Sound-attenuating air grille guarantees the correct operation of a ventilation system

Duco will be launching a new aluminium door grille in February. The DucoDoor is a compact grille with a very discrete design available in any colour. More...

energiVent FLOW
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Towergate Insurance, Europe’s largest independently owned insurance intermediary, now benefits from a comprehensive, low energy Vent-Axia air movement solution at its new headquarters in Eclipse Park, Maidstone’s ‘environmentally responsible’ business park. More...

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