The choice of a continuous whole-house ventilation system involved an analysis of the various installation options and systems available. Their performance, cost, and suitability for the TownHauZ and climate were all considered in order to make the best solution for indoor air quality, as well as cost and functionality.
One of the first options considered was to install a separate whole-house ventilation system with dedicated ducts. This was found to have a significant high first cost due to the additional material and labor required. As a result of this, additional options were sought after to reduce the install cost, as well as the operating cost with energy efficient features. Another option considered by the design team was to combine a heat recovery ventilation (HRV) and energy recovery ventilation (ERV) unit with the forced air conditioning furnace to deliver continuous ventilation to the entire house. This configuration was disregarded due a high operating cost and concerns with poor humidity control.
The ventilation system finally chosen by the design team was selected to address concerns with high initial and operating costs. This system is the Lunos e2 HRV fans. The fans are standalone units that are installed directly through the exterior wall requiring no ductwork. One pair of the Lunos fans will be installed on each floor of the TownHauZ to meet the required CFM rate for the whole house of approximately 50 CFM. Each pair of fans works together synchronized by a controller that periodically alternates the function of each pair of fans. So while one fan operates as supply, the other will operate as the exhaust, and every 70 seconds they will switch functions to create a balanced ventilation rate. MERV 10 filters will be installed in each fan to reduce air pollution that could enter from outdoors. The fans are also extremely energy efficient with heat recovery efficiency between 80-90%, and humidity recovery efficiency between 20-30%.