The issue with the ones with a built in tstat is when the ranco cycles off (it's an on off type thermostat, temp is reached, stat turns off, drops below a set temp, turns back on. You get the idea!!) when it cycles back on again the heater won't turn on, they have a safety feature where they won't turn back on after an outage! If they have a rheostat it's not an issue.
Sent from my iPhone using Tapatalk