The newest version of the federal Energy Star Qualified Homes program calls for a specific level, or exchange rate, of fresh-air ventilation to help mitigate indoor air problems in the tightly built homes that meet the new standard (see ASHRAE 62.2-2007), if not precisely how builders should achieve those levels. National green building certification programs follow a similar route.

A number of options exist, but an increasing number of builders are turning to heat and energy recovery ventilators (HRVs and ERVs, respectively) to deliver a controlled amount of fresh air in a whole-house scheme as opposed to installing several spot or local ventilation products.

While the air-quality contribution of an HRV or ERV is largely speculative and anecdotal, the units are rated by the Home Ventilating Institute and others for their energy recovery benefits and, in the case of ERVs, a measure of dehumidification.

Assuming, of course, that the units are properly installed and maintained over time. As relatively new products, HRVs and ERVs require their own attention to detail to perform as designed to reduce energy use and costs while delivering fresh air to the interior environment. Here’s how to troubleshoot common problems and educate your home buyers about maintaining the system.

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