High transaction fees, security vulnerabilities, and inefficiencies in traditional blockchain systems have long hindered the scalability and cost-effectiveness of real-time sensor networks in the Smart buildings. This study addresses these critical issues by introducing a novel integration of sensor nodes with IOTA-based Distributed Ledger Technology (DLT) networks. The proposed system not only reduces operational costs and network overhead but also enhances security through secure device authentication and communication. Employing state-of-the-art encryption techniques ensures secure and confidential data transmission between sensor nodes and the DLT network with cryptographic operations (0.00017s encryption, 0.00016s decryption), creating a tamper-resistant exchange system. Framed within the context of smart buildings, this research explores scalable and interconnected solutions designed to meet the dynamic security and performance needs of urban environments. The experimental validation demonstrates the system's effectiveness through comprehensive analysis of encryption and decryption performance, network transaction throughput (0.331 TPS), low latency (0.0168s), and energy-efficient power consumption across two distinct scenarios: (1) Normal Transaction conditions and (2) Traffic Congestion environment, where the system shows resilience despite 68% throughput reduction and significant latency increases under network stress.