Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Underachiever

I purchased this heater in hopes of heating a 20 x 10 area in my basement that was just refinished. It does a poor job concentrating the heat only in an area of about 5 X 10 feet in front of the heater. The temperature then drops off sharply. I would not recommend this heater for a large area or an area that is not well insulated.