When our 20 year furnace failed, I called Fagnan's. They have been our service technicians up until now.
When the technician arrived, I greeted him at the door. He immediately started telling us about how furnaces in homes like our are often too big. After a hour's service call, I was told that I needed an expensive part and that the technician would look for it the following morning. He also identified some other issues which he wrote on the work order. He told us that they were caused by the furnace being too big and that we should consider a replacement.
We were without heat for the night.
The technician called the following morning at the time he promised. He gave me the price of the part. I later learned that it was about twice the wholesale cost. He then advised me to replace the furnace and told me that Fagnan's had a special on furnace replacements. He gave me the price of the special, but did not identify the make of the furnace.
I became suspicious and asked for time to think about my decision.
I called another repair firm recommended to me by a friend for a second opinion. They came over and spent about an hour diagnosing the issue. They eventually discovered a broken wire connected to the expensive part and also replaced the igniter.
The furnace was running properly in about 90 minutes and has been working without issue for 4 days. The technician indicated on the work order that the parts and his service work were warranted for one year.
When I asked about the size and the other problems identified by Fagnan's, the second technician said that they were not major concerns to him. He recommended that the furnace be serviced more regularly and suggested an annual inspection. He felt that the furnace would be serviceable for the foreseeable future.
When I asked him about potentially replacing the furnace, he did say that we would save money on gas bills, but suggested that we take our time and considering a variety of options (make, model, efficiency) that fit our budget and interests in quality.