

A cheap solution suggestion, not sure if it fits your requirements:
- a dumb heater with manual switches
- a remote controlled power plug for the heater (e.g. zigbee)
- a remot thermal sensor (e.g. zigbee)
- a simple HA automation that checks temperature and turns the plug on for X mins
- a fire alarm to prevent that from burning down your building


There is an app called button mapper that lets you rebin the keys easily on the chromecast remote (google tv)