Pg 4 Healthy Homes Ventilation The advent of improved insulating materials and techniques have also created a major problem; inadequate ventilation. A tight seal is very desirable in regard to preventing drafts and insulating the house. But the tight seal doesn't allow the house to "breathe." That is, there is no exchange of fresh air to remove moisture, pollutants and odors. Such conditions target a house for "Sick Home Syndrome."   Energy Recovery Ventilators In winter, it's not practical to throw open a window and run a fan. A practical method for circulating air is necessary. One system of choice is an Energy Recovery Ventilation (ERV) system. An ERV provides moisture control, indoor air quality, and energy recovery. The ERV is based on a few simple principles: An Exchange of Air: The ERV brings fresh, outside air into the house while pumping stale, indoor air outdoors. An Exchange of Energy: Warm, stale air (including air condition air in summer) from inside the house gives its energy to incoming cool (warm in summer), fresh air from outside. The ERV transfers energy by passing both air sources very closely together in separate networks of ducts. The air doesn't mix, but the temperatures do. High performance ERVs can be about 80% efficient in exchanging heat in winter and about 30% efficient in summer. Some models have a pollution sensor built into the switch to immediately prompt an air exchange.   Old Homes vs. New Homes Older homes usually have a good deal of outside air infiltration: around inefficient windows, at the foundation, and through underinsulated walls to name a few. Although it is very energy inefficient, a small supply of fresh air enters the home. This is not the case with recently built homes. Insulating products like house wraps that protect outside sheathing, high quality fiberglass insulation and energy efficient windows all create a tight seal. The house has no fresh air exchange at all.   Central Vacuums One great way to improve indoor air quality is with a central vacuum system. These use a system of PVC pipes and outlets throughout the house which pull the dirt and dusty air back to a central canister located in a basement or garage. Central vacuums are generally much more powerful than portable vacs. And although the filtering on portable vacuums is improving, a central vacuum system has the foolproof benefit of exhausting the dusty air to the outside. It's most cost effective to install a central vacuum system during new construction. It's also possible to put one in during a remodel or as a standalone upgrade to an existing home. It's a project that CAN be done by an ambitious do-it-yourselfer. Beware -- the PVC pipe generally used is not the same as the PVC sold in home centers for plumbing systems. It's called "Schedule 20" PVC. The pipe walls are thinner and the connectors make more gradual bends to accommodate the flow of debris.   < Back | Next > < Back to Main Project Help

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