CSLB Class B General Contractor's License Practice Exam

When installing a warm air furnace on an exterior wall, what is the designated area that it should never be installed under?

1. Exhaust vent

2. Openable window

3. Both exhaust vent and openable window

4. None of the above

The correct answer is: Openable window

When installing a warm air furnace on an exterior wall, it is critical to consider safety and code compliance regarding the placement of the appliance. The correct choice indicates that a warm air furnace should never be installed under an openable window. This is due to the potential hazards associated with exhaust gases and the flow of air. If a warm air furnace is positioned directly beneath a window that can be opened, there is a risk that exhaust fumes from the furnace could enter the building through the window when it is open. This poses a significant health risk to occupants due to exposure to carbon monoxide and other harmful gases that may be emitted during the furnace's operation. Additionally, building codes are designed to prevent such installations to enhance safety and reduce the risk of hazardous situations. Exhaust vents, while also significant in terms of placement, do not specifically define a hazardous condition relative to openable windows in the same way. The consideration for installing under windows focuses primarily on the safety of indoor air quality when windows are opened, which can create an unsafe environment for the occupants.