It was sponsored by Spanish gas heater manufacturer Super Ser. Then, the same system costs as much to operate as an efficient gas heater. It is heated by a small gas heater that runs for 45-minute intervals. A correctly operating flued gas heater is usually safe. Just off this sleepout was "the bathroom with gas heater, set-in basin, bath and shower". A gas heater had to be turned on to heat the bath water. Yolanda had turned on the gas heater after closing all windows in the apartment.