If your house was insulated by spray foam, it becomes tighter, and air flow in the building is better and more controlled. Without mechanical ventilation, your house still breathes, but not enough. So buildings with spray foam insulation require mechanical ventilation.To consider the method of house ventilation, you should know your climate zone. The recommended method for modern buildings is installing HRV, heat recovery ventilators for buildings. They extract energy from outgoing air flow and diffusing this energy to ingoing air.
This kind of ventilators often performs better than traditional exhaust fans, because with them you can choose specific place in room for air exhaust and intake. Traditional fans may also be the cause off condensation problems. At first, you need to choose and buy appropriate HRV for you house, depending on its power and other characteristics, price and additional options, warranty conditions, and the trademark. Such companies as Fantech, Lennox, Broan, and Venmar are popular HRV makers, but you can choose ventilation systems made by other companies. Then, after buying heat recovery ventilators, you also should order their proper installation in the rooms of the house or other building.