Boilers need tune-ups too. At the same price as a furnace or AC tune-up, a boiler tune-up keeps the heating system safe, reliable, and efficient.
Pictured are 2 separate boiler tune-up before-and-afters, looking at the inside of a modulating condensing boiler. The black and green scaly gunk was preventing heat from transferring to the water, thereby making the boiler far less efficient than the advertised 95% AFUE. The boiler depicted in the 2 lower photos was severely neglected and needed further work. We fixed it all up, but we forgot to snap a pic afterward.