Purchased for my elderly father after his central heating boiler broke down and he didn’t have any hot water. Brilliant piece of kit, would highly recommend. Haven’t tried filling it to the top but, at half full, and with the setting on number 3, it takes only about 10minutes to warm water sufficiently for a wash or to do the washing up. Obviously would take longer to reach the boil, but you can use a kettle if you need boiling water. In built thermostat keeps water at desired temperature. Although made of plastic, the sides do not get uncomfortably hot, so no real danger of scalding (although I’ve not tried it up to the boil). Would highly recommend if you’re looking for a portable, effective water heater.