Space heaters are small, usually portable, units for heating a specific, enclosed area. They are available in free-standing, wall-mount chimney vent, or wall-mount direct vent, which uses natural gas. Other types include gravity units and fan units. All of these can be regulated with either a built-in or wall-mounted thermostat. Since space heaters can give off a substantial amount of heat, avoid placing them too close to furniture or storing anything near them. This can obstruct air flow and create a fire hazard. In household heating appliances such as space heaters, troubleshooting is relatively simple. If your space heater breaks down, the failure is usually the result of a break in the electrical circuit. Check the fuses and circuit breaker first to ensure they are in proper working order. Then, check the power cord to ensure it is not split or frayed. Contact your local appliance dealer for more specific information.