A thermostat cross-reference guide is used to compare different thermostats by the features they offer. This guide can also be used when replacing an existing older-model thermostat by listing the comparable specifications of the newer-model replacement.
Thermostat cross-reference charts are often separated into programmable, mechanical, digital and line voltage categories. Programmable thermostats often offer seven-day programming features. Mechanical thermostats sometimes offer combined heating and cooling features as well mercury-free units. Cross-reference guides are typically separated by thermostats using a common wire and those without. Thermostats are typically connected directly to the heating system and may require batteries to function correctly.