Not really low cost but the Zen17, if you have space for it, will work as dry sensor contacts.
5/12/24 VDC Power.
Extra sets of sensor/output contacts for future projects (Sirens, Lights 
).
Features
Ÿ Monitor inputs independently from output control
Ÿ Powerful dry contact NO/NC relays to control loads up to 20 A for NO
Ÿ Perfect for DC motors, pumps, commercial gates, or HVAC equipment
Ÿ Control up to 2 connected loads independently or together
Ÿ Z-Wave or optional wall switch control (toggle or momentary type)
Ÿ Built-in timers for each relay to simplify automation
Ÿ Built-in Z-Wave Plus signal repeater to extend network range
Ÿ Powered by 12-24 V DC/AC or USB C port for easy set-up
Ÿ Wall mounting and minimal design for clean installation
Ÿ NEW 700 Z-Wave chip, S2 security, and SmartStart
