Heat recovery ventilators are used to improve the efficiency of a house or other building structure. A heat recovery ventilator provides fresh air into the house or building while exhausting an equal amount of stale air. During the winter months, the heat recovery ventilator warms the incoming cold fresh air with heat reclaimed from the exhausted stale air. During the summer months, the cool outgoing stale air from air conditioned homes is used to cool incoming fresh air.
Heat recovery ventilators all have the same basic structure. A heat exchange core is mounted within a housing for defining two separate airflow paths, an incoming path and an outgoing path. The heat recovery ventilator normally has two fans mounted on the housing for creating the requisite air flows. A typical housing for a heat recovery ventilator is illustrated in U.S. Pat. No. 4,874,042.
In recent years, the heat recovery ventilators have been becoming increasingly more complicated with new added features. Heat recovery ventilators are now being fitted with an electric defrost element and a temperature controller in the incoming fresh air supply for defrosting the heat exchange core if the outside temperature falls below a pre-determined freezing temperature.
As these features are added, the space within the housing becomes more limited. It is possible to increase the size of the housing. However, this option is not desirable in terms of consumer requirements and shipping costs.
In the servicing of heat recovery ventilators, the fans are the single most part which requires repair and replacement. However with the increase in the number of features and limited space within the housing, it becomes increasingly more difficult to service a heat recovery ventilator and have access to the fans.