Turn on air conditioner and heater at the same time

[Byungeon0]

Some of guests turn on air conditioner and heater at the same time.

Anyone knows the reason?

The heating system heat on floor. Here is korea.

[Bob297]

@Byungeon0 
That makes no sense

[Branka-and-Silvia0]

A couple from Asia did it to my neighbor. They turned on A/C + electric radiator at the same time while the temp outside was +35C, top summer season. They didn't open the windows once during their stay.
Within a week they managed to grow about 50 cm high mold everywhere in the apartment without even noticing it. (Their review was 5* and they had "a wonderful stay" )
Result: a few hours of cleaning with bleach + a month of airing and venting + dehumidifier + repainting all the walls.
Idiots.

[Mike-And-Jane0 · Accepted solution]

@Byungeon0 If it can be done then at least one guest will do it. Can you get an electrician to wire the aircon and heater circuits so only one can be live at any time?

[Byungeon0]

Thank you for a good advice. I will try it.

[Fred13]

An odd choice to be able to turn both at the same time, since they are opposites.