- Modulating design continuously adjusts heating level in small increments to match the degree of comfort you need precisely. - Variable speed blower provides quiet, efficient circulation. - Integrated ClimaTrak Comfort System tailors operation to the needs of your locale. - Compact 33-inch height fits the space in your place. - Good Housekeeping Seal. This model is proud to have earned the Good Housekeeping Seal a nearly century-old symbol of quality and trust. - 10 Year Limited Parts and Lifetime Heat Exchanger Warranties. This product is covered by some of the best warranties in the business: 10-year limited parts and lifetime heat exchanger warranties. - Variable Speed Technology. This blower technology adjusts gradually to deliver precise comfort without wasting energy.