There is a brand of aircon with cooling/heating feature called General, an india-japanese joint venture. The Sabah dealership disappeared long ago, but the dealer in west malaysia still exists according to their website.

FE Denki Sdn Bhd

Telephone:
+603 5525 5048 (for Sale)
+603 5525 5048 (for service and repair)

I had a unit for 11 years until the compressor died...no spares. On my model the heat function had to be turned on by flicking a switch on the blower unit. It came in handy during colder monsoon months where the daytime temperature could drop below 20C in my area which would make the resins I was working with too brittle to handle.

Silly to install heater for 30c 🤦‍♀️ heater is meant for cold climate countries to make the temperature more bearable to the human body ie 20c above

Myself even 15c consider warm so it is person body who cannot regulate their body temperature to cope with external temperature

wear jacket