Things to search for whenever shopping. C-wire requirement Many smart thermostats require more power that is electrical a set of batteries can offer. C-wire requirement Many smart thermostats require more power that is electrical a set of batteries can offer. Happily, they don’t need therefore power that is much they have to be attached to the wall surface. They depend rather on low-voltage energy given by your HVAC system. Numerous smart thermostats need the existence of A c that is dedicated) cable for this specific purpose, while some can siphon electricity from another supply, usually the R (energy) ...