Right you are. All manual thermostat controls on direct blow A/C units refer strictly to the cooling section of the unit. If you have a heat pump, it would control that also. Your heat strip is either on or off. You will find that they do not provide a lot of heat, but will take the chill out of the air.
I had a couple of roof air units in a motor home for 5 years and found the heat strips to be just north of worthless for heating applications.
Lew Farber...RVIA Certified Master Tech...ABYC Certified Master Marine Electrician
SOLAR TECH ENERGY SYSTEMS, INC.
AM SOLAR ...MAGNUM…VICTRON ENERGY...LITHIUM & LIFELINE BATTERIES…MARINE REFRIGERATION