The Most Efficient and Quietest Oil Furnaces Available: Dave Lennox Signature® Collection You need an energy efficient furnace, which is why our Dave Lennox Signature Collection oil furnaces were built with variable speed motors. These motors adjust their speed relative to the amount of heat needed which helps you reduce the amount of energy used and decrease operating sounds. Now that we’re talking about operating sounds, SilentComfort™ technology is also a key feature in these products, keeping your home warm, cozy and quiet – unlike some traditional heating systems. Learn about the Dave Lennox Signature Collection oil furnaces we offer at Nisair Air Conditioning in Stuart below. To determine which system will work best for your family, call us at 772-318-4252 or make an appointment online. Are you looking for someone to assist with your oil furnace maintenance and repair needs? Nisair Air Conditioning in Stuart can take care of it all. Just give us a call at 772-318-4252 or use our online scheduler to set up an appointment. * Annual Fuel Utilization Efficiency (AFUE) measures how efficient the appliance is in converting its fuel’s energy into heat over the course of a year.