Bests & Worsts Reviews from Amazon

There is no doubt that short and long term Carbon Monoxide exposure can cause brain damage and/or death. A Carbon Monoxide Alarm (CWA)detector is even required in all homes in my state of Pennsylvania and many other as well; yet I know of no one who has one in their home here. So, after getting a new HVAC system I thought the time had come to be the first one on at least my block to break down and get a CMA. A small number of other Amazon Customers have reported (one star) that their Kidde CMA demonstrated random readings, Unfortunately, mine did as well. Readings of 22-29 ppm were always the readings in my house for two days. I then took it outside for a day and it produced the same readings! This is not acceptable to me since 22-29 ppm are either definitely problematic or at least close to it, as follows: [OSHA PEL] The current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) for carbon monoxide is 50 parts per million (ppm) parts of air (55 milligrams per cubic meter (mg/m(3))) as an 8-hour time-weighted average (TWA) concentration [29 CFR Table Z-1]. [NIOSH REL] The National Institute for Occupational Safety and Health (NIOSH) has established a recommended exposure limit (REL) for carbon monoxide of 35 ppm (40 mg/m(3)) as an 8-hour TWA and 200 ppm (229 mg/m(3)) as a ceiling [NIOSH 1992]. The NIOSH limit is based on the risk of cardiovascular effects. [ACGIH TLV] The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned carbon monoxide a threshold limit value (TLV) of 25 ppm (29 mg/m(3)) as a TWA for a normal 8-hour workday and a 40-hour workweek [ACGIH 1994, p. 15]. The ACGIH limit is based on the risk of elevated carboxyhemoglobin levels [ACGIH 1]. Therefore, an actual/theoretical (relatively) small leak of 22-29 ppm could be harmful be over time. But, if readings of 22-29 are this units "zero point" then how would I know? Why have this unit!? Not good. So, I sent this "Kidde" back (for free) and exchanged it (Love Amazon!) for a "ProTech 7035 Lithium Battery Powered Carbon Monoxide Detector with Digital Display and Memory". This unit has a safer/lower sensitivity level of 10ppm (Not apparently 30ppm or more.) which, now that I have looked into it, is as low as I can find for under ~$700 or so! Yes, the ProTech costs twice as much as the original Kidde; but only that...The reason is that it works on a different, more efficient and accurate principle (and is, of course, more expensive) than the Kidde. At least for me and my family, I look forward to receiving it.