HRVs Vs. Whole House Dehumidifiers in HVAC

HRV

• An HRV (heat recovery ventilation) system can be connected to an HVAC (heating, air conditioning and ventilation system) or installed as a window unit in one or more rooms. The purpose of an HRV is to transfer fresh air into the home and exhaust stale air outdoors. In the winter, an HRV transfers heat from the exhaust air stream to the incoming air stream, and in the summer cooling season it does the reverse. As a result, the indoor air quality is improved during all seasons of the year.

Whole Home Dehumidifier

• A whole home dehumidifier measures the condition of air in the home in terms of humidity and stuffiness. When the dehumidifier is attached to the home's HVAC system, it can remove up to 90 pints of evaporation and condensation from a home on a daily basis. The unit has its own thermostat that measures the humidity level and goes into operation when it senses that dehumidification is needed. At that point, an air-cycling feature will activate with the HVAC blower to remove humidity from rooms and exhaust it outdoors so that the indoor air quality is more balanced.

Similarities

• HRV and whole home dehumidifiers improve indoor air quality by reducing humidity levels. Both can be attached as a component of an HVAC system, or installed as freestanding appliances in individual rooms. HRV and dehumidifiers are electric-powered. An HRV or dehumidifier system can be installed in a home during construction or after a home is built. However, installations in older homes may be costlier if ductwork, pipes and other ventilation equipment have to be retrofitted. In some cases, it may be more cost-effective to install one or more window units in an older home.

Differences

• An HRV removes stuffiness without sacrificing heat, as would be the case if you opened a window while heating a home. The main function of an HRV is to exhaust “old” air while maintaining the heat energy. Reducing humidity is not the primary function of an HRV. However, in the process of exhausting stale air and distributing fresh air, it does remove air that is humid and stuffy. An HRV can operate as an exhaust unit only, or as a integrated centralized unit that exhausts air and exchanges it for fresh air. A whole home dehumidifier, on the other hand, focuses solely on maintaining the right level of moisture in the air, and not on exchanging “old air for new air.” Those who suffer from allergies or asthma may breathe more comfortably by having both types of systems in their homes, especially during the winter season when the indoor air can become too dry or too stuffy.