This is such an obvious product to buy. The standard CO detectors out there keep might you from dying, but they don’t alert you until you have already been breathing very toxic levels of carbon monoxide for a long time. I want to be alerted when a problem with my furnace is just starting, and levels of carbon monoxide are not yet life threatening. Why would you want to wait until the problem is so serious that it is life threating? It makes no sense.
Maybe people just don’t want to spend the extra money on a more sensitive carbon monoxide detector like this one. But to me it is well worth the money.