Several two-wire thermostat models are available on Amazon.com and ACWholesalers.com as of 2015. This type of thermostat is generally compatible with heating systems only, rather than cooling systems.
Two-wire thermostats available on Amazon.com include manual options by Honeywell, Coleman and King Electric, as well as digital varieties by Honeywell and Lux. Most of these thermostats are not programmable and provide basic temperature readings.
ACWholesalers.com sells both mechanical and digital two-wire thermostats by brands such as Lux and Honeywell, that are also for heat-only systems. Site visitors can compare up to four thermostats at a time and view the specifications and price differences of each.