I tunned three furnace at my home. Generally they replace filter for free but I had speacil filters. so they told me they will order for me at $75/ea and replace it later. I told them I will buy filter myself and they can replace them. I found OEM filter for $17/ea. They changed tone saying if I buy filter then I have to pay additional service fee of $130 to replace filter. Total greedy staff. I will avoid them in future.