  We consider suspened bilayer graphene under applied perpendicular electric
bias field that is known to generate a single particle gap $2\Delta$ and a
related electric polarization ${\cal P}$. We argue that the bias also drives a
quantum phase transition from band insulator to superfluid exciton condensate.
The transition occurs when the exciton binding energy exceeds the band gap
$2\Delta$. We predict the critical bias (converted to band gap),
$\Delta_c\approx 60$ meV, below which the excitons condense. The critical
temperature, $T_c(\Delta)$, is maximum at $\Delta \approx 25$ meV,
$T_c^\text{max}\approx 115$ K, decreasing significantly at smaller $\Delta$ due
to thermal screening. Entering the condensate phase, the superfluid transition
is accompanied by a cusp in the electric polarization ${\cal P}(\Delta)$ at
$\Delta\to\Delta_c$, which provides a striking testable signature.
Additionally, we find that the condensate prefers to form a pair density wave.
