About McCarthy Heating Oil Operating out of Quaker Hill, CT and serving Southeastern Connecticut, McCarthy Heating Oil provides service in all facets of the fuel business, including complete heating system installations and air conditioning. Our primary aim is and always has been to maintain a personal relationship with our customers that only a small, family-run business can offer. Our business is into the third generation of our family as well as some of our customers' families, and we are enjoying every minute of it!.