<prompt> Human: Beware of unsolicited furnace inspections in the winter. Unscrupulous companies will Red Tag and disable your furnace to try to pressure you into replacing it. Sometimes when there is littlenothing wrong.STORY So my wife and I live in a house built in 1915 that we bought in 2010. When we bought it we knew the HVAC was middle aged say 9899, but it still ran fine. We have had to have people out to do minor repair on the furnace twice, and I think had one duct cleaning, as well as a variety of plumbing work.Well one of the companies that has done work for us in the past contacted us out of the blue about a month ago looking to schedule a free furnace inspection. That seemed slightly suspicious, but sure why not.So they came out and did the inspection, found two cracks in the heat exchanger which could lead to carbon monoxide leakage. They did show me the cracks on a boroscope, not just on their phone. One was in a non critical area, and the other was absolutely minute I have done a lot of research since.So they tell me they need to Red Tag the furnace and that they are going to disable it. Keep in mind it is about 5F out and we have a 3 month old. I put up some fuss and they have a second more senior technician in to do some more tests, and he confirms that they are going to disable it.But they are generously going to bring me some space heaters for us to use, get me a quote on a new furnace, and show me how to re-enable this one if I absolutely need to but that I would be accepting full liability if I restarted it.Well they of course do get me the quote for repair that is more than a new furnace costs. And by say hour 5 or 6 in my house made a quote on replacement that was very high. But I told them I needed to think about it, so they left without ever showing me how to re-enable the furnace, though they did leave the space heaters probably legally obligated to.I asked for and got some other quotes from some other companies, one of which was roughly half as much, and I also got a second inspection. This one said the heat exchanger was fine and that the very light cracking was pretty typical for a even 8 or 10 year old unit, much less a 1617 year old one. Most importantly they did actually test for carbon monoxide leakage and found none whatsoever. There was less in the house than outside, and the biggest source in the house by far was our brand new stove.When I confronted the original company with this information they admitted they just assumed it was leaking, and didnt actually test the air.So while we are going to need to replace the furnace in the next couple years, it does not need to be immediately, and it is not posing any danger to us. If you search around online which I did you can find a lot of articles about this type of scam.TLDR Always be suspicious of free or unsolicited anything. Always get multiple quotes, and if preferable, word of mouth recommendations. Make sure anyone red tagging your furnace actually tests for carbon monoxide which they are supposed to.  <response>: FYI any crack in a heat exchanger is enough to condemn the furnace. Even if it isnt leaking now eventually it will be. A furnace technician is required by law to red tag any furnace that is found to have a cracked exchanger so in this instance they are just doing theyre job. Why people would rather just cross their fingers and hope their entire family doesnt die of carbon monoxide poisoning at night instead of just replace the furnace is beyond me but hey its your life. 