This weekend I got an email from my nephew who lives in New Hampshire. He recently moved into a home and they finished the basement and attic. Now, he had a contractor come in and he was telling him that he needed  an additional 50,000 BTU larger boiler to heat the house. Since he knew I retired from heating and air  conditioning, he wanted my opinion. My first question to him was, ” How did the contractor determine that he needed an additional 50,000 BTU’s to heat the new areas?” Then I asked, ” Did he do a load calculation? Was he basing it on how many feet of new baseboard radiators he was installing? What water temperature is the existing boiler operating at?”  The existing boiler may be large enough to handle additional baseboard radiators. I told him that basements usually are not included in load calculations so that…