I was skeptical going in to this cut-rate furnace tune-up deal. I expected I may be paying good money to be told how much I needed to spend on my furnace (which was working fine, but had not been serviced in several years). The heating & AC Boise service technician was the nicest guy. Very personable, and knowledgeable about my furnace. He went about taking apart and cleaning the parts. Then, uh oh, you have a cracked heat exchanger, and it's not worth fixing this kind and age of furnace. He wrote me up an estimate for a new furnace, installed. He told me scare stories about dying in the night of carbon monoxide. The Boise plumber from Einstein told me about new standards that will make it much more expensive to replace a furnace in the near future. I told him I'd give him a call, then did some research.
First, the heat exchanger and a bunch of other essential parts CAN be replaced on this furnace for about 1/3 of the cost he gave me for a new furnace.
Second, there's a positive pressure situation in the furnace such that when there is a crack in the heat exchanger, clean air leaks into the fire box, NOT carbon monoxide leaking into the clean air. And if there's a really huge failure in the heat exchanger, the furnace is likely to shut down - not kill you in your sleep.
Third, the particular type of furnace I was offered is seen as low end, and likely to need MORE service sooner rather than later.
Lastly, after I told him I'd call, he called back repeatedly and left messages on our phone. Clearly this Boise heating and air conditioning owner was anxious to close the deal. His messages were very personable and friendly, but unconvincing.