Thermostat that can use external temperature sensor?

If you aren’t planning to replace your thermostat, check out this app which can use existing thermostats and external temperature sensors. You can set it to use remote sensors for specific schedules (e.g. at 7pm use the top floor sensor where as at noon use the basement sensor - say you’re working in the basement and sleeping on the top floor)

The basic version is available on the link above, for the advanced version with the remote sensor you’ll need to get access to the server.