Fresh Air System Vs. Heat Recovery Ventilator

Fresh Air Systems

• The overall goal of a fresh air system is to exhaust stale air from a room, and some systems “exchange” the old air for new, fresh air. Manual fresh air systems can be as simple as doors and windows that are opened to allow fresh air inside a home or building. Mechanical appliances can be as simple as turning on a freestanding fan used in conjunction with an open window to blow stale air, fumes and odors from the indoors and exhaust the stale air outdoors. Advanced mechanical devices include fan-operated ventilation systems. They run on electricity and are usually turned on manually by flipping a switch, similar to a light switch. Ventilation systems “freshen” the air by using exhaust fans to draw out fumes and odors, and are commonly installed in kitchens and bathrooms.

Heat Recovery Ventilator

• A Heat Recovery Ventilator (HRV) is a type of fresh air system that removes stale air and exchanges it for fresh air. It heats the incoming, exchanged air in the winter and cools the incoming exchanged air in the summer. There are three types of HRV systems: exhaust-only; central-fan-integrated, supply ventilation systems; and balanced ventilation systems. Exhaust-only systems simply remove old air and do not bring in fresh air. Central-fan-integrated systems are connected to a home’s HVAC system and exhaust and exchange air in rooms throughout the home. A balanced ventilation system is a combined HRV and Energy Recovery Ventilator (ERV). The ERV component adds and removes moisture, similar to a dehumidifier.

Similarities

• Fresh air systems and HRV systems make homes more comfortable and improve the indoor air quality. By reducing indoor air pollutants, such as dander, mold, dust and pollen, the air you breathe is healthier, and health risks are reduced for those who suffer from allergies, asthma and other respiratory-related illnesses. Fresh air and HRV systems are powered by electricity and only rely on gas or oil if they are connected to a home’s HVAC system.

Differences

• An HRV (or ERV) system can remove stale air, exchange it for fresh air and do so with minimal heat loss in the winter and cooling loss in the summer. Other fresh air systems, such as ceiling mounted ventilators, cannot be attached to an HVAC system, and they do not exchange old air for fresh air. They are primarily exhaust systems. In addition to that, an HRV can run simultaneously while heating or cooling devices are in operation and are automated devices that turn on and off when the thermostat and room conditions dictate that the unit should operate.