The accurate and fast sensing of the radio spectrum is one of the key requirements of any Cognitive Radio (CR) architecture. Wavelet packet-based spectrum estimator (WPSE) is a newly developed method for the detection of active users or spectrum holes in the spectral domain. Various wavelet families with different wavelet parameters exhibit different detection performances. In this article, the receiver operating characteristics (ROC) is considered for the performance evaluation of wavelet packet-based spectrum estimator for a wide range of wavelet families, both orthogonal and non-orthogonal, with different wavelet parameters. Exploiting the underutilized radio spectrum, an efficient wavelet packet-based spectrum estimation model with reduced number of sensing measurements is also proposed. The developed model exhibits a significant reduction of number of sensing measurements with a good detection performance.