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Increasing your home's ventilation
Written by Administrator
Wednesday, 06 May 2009 18:29
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Many people experience humidity problems in their home for the first time following a renovation. New doors and windows, and even new siding, can increase the airtightness of a house. A prime aspect of many renovations are to improve the energy conservation quality of the exterior walls and roof. In achieving this increased performance, a deficiency of fresh air inside the house results. There are three main requirements for fresh air in your house: Make-up air, combustion air and ventilation for occupants. Make-up air air is the air required to replenish that which is exhausted by household equipment such as exterior exhaust central vacuums, cook top fans, bath fans and clothes dryers. If all these fans are running at the same time, they can require approximately 750 cubic feet per minute of make up air brought into the house. Without make-up air, a down draft from fuel burning appliances such as furnaces and fireplaces will result, forcing deadly carbon monoxide gas into the house. Combustion air is the air required for the burning of fuel in appliances such as furnaces and fireplaces. Without oxygen the fuel will not burn. The building code requires the installation of an outside air supply to all furnaces, woodstoves, etc.. If youe furnace or fireplace currently does not have an air vent to supply it with outside air, make this part of your renovation. Ventilation for the occupants is the least understood requirement of air. The Ontario Building Code requires one third of the air in the house to be changed every hour. Given that renovations can improve energy conservation in a house through the installation of new windows, insulation, vapour and air barriers and high efficiency furnaces, the natural air infiltration into the house is reduced. When renovating, the objective is to introduce fresh air in a controlled manner and distribute that air throughout the house. The purpose of fresh air is to reduce pollutants within the house, be they high humidity, odours or toxic gases. (Common items like carpeting, kitchen cabinets, flooring adhesives and paint all give off toxic gases such as formaldehyde.) The most common method of increasing a home's ventilation is through the installation of a heat recovery ventilator (HRV). The HRV uses one fan to constantly bring fresh, outside air into the house, and another fan to exhaust from the house an equal amount of stale air. Like it's name suggests, an HRV recovers your precious heat from exhaust air before discharging it to the outdoors. Through a heat exchanger within the HRV, the cooler incoming air is preheated using the warm exhaust air. Most HRV's use your existing furnace ducting to distribute fresh air to all rooms and occupied areas, so they can be installed as part of your renovation without major ducting revisions. Renovating to create a well sealed house is actually an opportunity for healthier living. Take this opportunity to install proper, controlled ventilation and then enjoy a healthier indoor environment. Lynn Schmidt is a partner with Solterra Developments, an Ottawa firm specializing in energy efficient renovations and housing. |
