The furnace is the beating heart of the home, pumping warmth to its furthest extremities and showing affection for the jolliest of men by covering them in soot. Spread the love with today’s Groupon: for $29, you get a furnace tune-up (a $139.99 value) and a carbon-monoxide detector (a $30 value) from Green Tree Heating & Air Conditioning (a $169.99 total value). This deal is valid within a 25-mile radius of Green Tree’s office, located at 4417 South 134th Street.

The management team at Green Tree Heating & Air Conditioning instills more than 20 combined years’ worth of HVAC wisdom in each of its field operatives, who deftly whip all makes and models of furnace into winter shape. Fatigued furnaces enroll in a 25-point tune-up boot camp before basking in the warm glow of pride in their newfound ability to operate cleanly and efficiently, freeing up dollars once spent on power bills and hot-lava wall insulation. The procedure includes cleaning or checking of gas burners, the pilot flame, and air filtration, along with full inspection of the combustion chamber and anger levels, among other steps. Once the furnace is restored to a clean bill of health, the serviceman outfits the home with a carbon-monoxide detector for the safety of the building’s residents.