The newly discovered even-denominator fractional quantum Hall effect at filling factor $\ensuremath{\nu}=\frac{5}{2}$ has been studied at ultralow temperatures. While ${\ensuremath{\rho}}_{\mathrm{xx}}$ is not found to vanish in the temperature range studied, the minimum in ${\ensuremath{\rho}}_{\mathrm{xx}}$ is seen to drop at the lowest temperatures. While this drop is insufficient to determine the energy gap, $\ensuremath{\Delta}$, it may be combined with the temperature dependence of the background resistivity to give a value of $\ensuremath{\Delta}\ensuremath{\sim}26$ mK. Because of the high electron-phonon relaxation rate, ${\ensuremath{\tau}}_{\ensuremath{\epsilon}}^{\ensuremath{-}1}=(2.9\ifmmode\times\else\texttimes\fi{}{10}^{3}){T}^{3}$ ${\mathrm{sec}}^{\ensuremath{-}1}$${\mathrm{K}}^{\ensuremath{-}3}$, a minimum electron temperature of 9 mK could be obtained with a residual heat leak of 8\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}14}$ W. It appears likely that ${\ensuremath{\rho}}_{\mathrm{xx}}$ approaches zero as $T\ensuremath{\rightarrow}0$.