Question

question 2
if the back - up heat is electric, when should the electric heat be shut off?
when the relative humidity drops below 50 percent
when the relative humidity exceeds 50 percent
when the system drops below the balance point
when the cop is greater than 3.0
when the system is operating above the balance point

Explanation:

In heating - cooling systems, electric backup heat is typically shut off when the system drops below the balance point. The balance point is the outdoor temperature at which the heat pump alone can no longer meet the heating demand of a building, and backup heat (such as electric heat) is engaged. When the system is above the balance point, the heat pump can operate efficiently without the need for backup electric heat. Relative humidity and COP (Coefficient of Performance) are not directly related to the on - off operation of backup electric heat in this context.

Answer:

when the system drops below the balance point