Instruct: Classify a review into positive or negative sentiment.
Query: Great while it worked.

I love these heaters while they work. I had previously purchased a Vornado digital heater and it worked for about 4 1/2 years and then the fan stopped working. This heater worked great for about 13 months (used nightly for 7 months not in use for 6 months)...then the fan stopped working. Disappointing for the price ~$100. If the heater worked for 4 years then I would have given it 4-5 stars, Since it was only 13 months...1 star.