Most space heaters will be effective with small rooms, so long as there’s nothing blocking the airflow. There are various types of heaters that can warm large rooms up to 1,000 square feet, such as electric heaters, infrared heaters, fireplace heaters, and propane heaters. In general, oil-filled and panel heaters are suitable for rooms smaller than 300 square feet. The best space heater for a bathroom is one that is designed to heat up a large bathroom.