Reddit reviews First Alert Wireless Battery Operated Smoke & Carbon Monoxide Alarm (2 Pack)

Sure! I'll always answer questions related to something I know a lot of parents worry about.

Code requirement, for new construction (meaning you are building new, or performing a 'substantial' renovation) require a hard-wired, single breaker, smoke/CO system (meaning all the detectors are physically wired together and draw their power from a single breaker, with nothing else on it). You are required to have 1 CO/Smoke combination detector within 15 feet of all bedroom doors (and 1 detector can cover multiple doors if within a 15' radius, but if you have a bedroom by itself in the house, it requires a combo detector there. Also, a room with a closet is consider a bedroom if it is not a bathroom.) The code also requires a smoke detector IN every bedroom. Let's see if I can get my Reddit fu working here.

Code Requirements for NEW construction

• All wired together and drawing power from the building, not primarily battery.
  
  
• 1 Combo smoke/CO within 15' of a bedroom door, or room used for regular sleeping
  
  
• 1 Smoke INSIDE each bedroom
  
  So those are the BASIC requirements for new builds. Updating your own home comes with the caveat that there are generally no permitting or inspection requirements for this. So code might as well be moot.
  
  To answer your question directly: You CAN put combo detectors everywhere. The only cost to you is money. Combo detectors everywhere will aid you in detecting someone doing something stupid (not saying you WILL but I've seen it), like putting a kerosene heater inside because it's cold. However, you MUST, AT LEAST, put combo detectors in your hallways. Think of the logic. The detector must be in a place where it is in the presence of CO, and CO is only produced by combustion items. It is highly unlikely that there will be a CO producing item in a bedroom, but it is highly likely that your furnace downstairs could produce CO, which will then travel through your hallway. By time it reaches your bedroom, it could be throughout your house. In short, putting combo detectors in bedrooms, and only fire in your hallway, is a recipe for disaster.
  
  Now, here's the good news and one of the wonders of modern technology. When you purchase your detectors I recommend you purchase enough to replace your ENTIRE house. Do not mix old and new, Yes, I know, expensive. Also, replace your detectors with a recognized brand, with wireless interconnect like this Kidde Combo alarm,, or this First Alert alarm. What the interconnect feature means is that if one alarm goes off in your basement (or wherever is farthest away from you asleep), the alarm that is IN your bedroom will also alert. One goes off, they all go off. This interconnect is a requirement of the code, but again, with no inspections people tend to cut corners.
  
  As for placement, for example, I have a detector in every room of my house that could possibly have someone sleeping in it. One outside the bedroom doors in accordance with the 15' requirement. One at the top of my stairs because smoke and fire rises, that detector will likely get the alert first. One is in my boiler room, where CO is likely to come from first. I also have a standalone detector in there because I like redundancy. Word of caution. Do not place detectors in your attic (too hot, will kill detector resulting in false alerts), or in bathrooms or outside bathrooms (steam produces false alerts). Also, put a detector OUTSIDE your kitchen door, but not IN the kitchen.
  
  In short, you can't have TOO many detectors (as long as you adhere to the word of caution above). The National Fire Protection Association (NFPA) reports that 3 out of every 5 fire deaths resulted from either no detectors, or detectors that were dead/disabled. There is NO excuse to not have functioning detectors.
  
  I can always elaborate on anything, this is kinda my thing ;)
  
  DISCLAIMER. CO DETECTORS WILL DETECT CO IN VERY SMALL QUANTITIES. REGARDLESS OF THIS FACT, TREAT EVERY CO ALERT AS A LIFE THREATENING EMERGENCY. CO GAS CAN INCREASE RAPIDLY AND OVERWHELM YOU. SHOULD YOUR CO DETECTOR GO OFF, CALL THE FIRE DEPARTMENT