First Alert Battery Powered SCO500B Wireless Interconnected Photoelectric Smoke and Carbon Monoxide Combo Alarm with Voice and Location

I purchased two of these after being unhappy with First Alert ZCOMBO made for Ring, which I returned. This model interconnects with other SCO500B models so that if there is an alert in another part of the house, all alarms beep and give a voice alert. These units cannot connect to my Ring Alarm system. That is fine with me as I discuss in my review of the ZCOMBO model. I had no problems at all with setting up these two units and choosing the voice location feature. So far, no false alarms and the units are working fine. I have read the "one star" reviews and people have had false alarms after a period of time. Mine have been up for one week with no problems but if I start getting false alarms, I will update this review. The distance that these interconnect seems good as I have tested these two in different parts of my house. I will probably buy two more for other areas. One thing that I like about this design is that if it detects CO, the alarm goes off and then it speaks the CO level to let you know how much CO has been detected.As I discussed in my other review of the ZCOMBO unit, people should not just assume that getting a CO alarm means that the unit is broken. There are many possible reasons why CO may be in your house and before declaring them defective, it is important to get a professional or the fire department to check your house. If you do an online search of CO in your house you will see that it is possible that a crack can develop in a furnace causing CO to mix with the heated air. Also, gas appliances such as heaters and even gas stoves, if not vented correctly can cause CO to enter a house. If one of these signals a CO alarm, take it very seriously because your life could be at risk. Don't ever assume that the alarm is simply broken until you are absolutely sure it is.I read a review of this item saying that the alarm on these units might not be heard by older people with hearing loss. The alarm on these units is very loud and someone would really have to be very hard of hearing to not hear this. In fact, when setting these up, you should probably wear ear protection because the alarm is very loud. I would recommend that people wear ear plugs even when testing these alarms.When setting these up, it is important to follow the instructions on the enclosed sheet because it is not easy to figure out without instructions. I found that the setup was easy when following the instructions. There are also some reviews here that have setup instructions, which can also be helpful.I consider these the best units that I could find for warning me about fire or CO when I am home. The only problem is that it will not notify me if I am away from home. I have decided that I am also going to buy two Nest Protect Smoke/CO alarms, one for each level of my home and in rooms that do not have this unit, the First Alert SCO500B. It is simply too expensive for me to buy six Nest Protect alarms which would be close to $700. I think that buying four of these units and two Nest Protect units, I can get a good smoke/CO alarm system at a reasonable price.In the future, if I decide that I want to connect these alarms with my Ring Alarm system, I will purchase a Ring Listener which is designed to be installed near and alarm and will send an alert to the Ring alarm monitoring company. I am still worried about connecting my Ring Alarm with smoke/CO detectors. The reason is that if there is any type of alarm sent, even false ones, Ring monitoring will send out the local fire department and they cannot be recalled. In my city, false alarms will get fined at increasing amounts and your alarm license can be banned for too many false alarms.I think that the First Alert SCO500B is a good smoke/CO alarm and I would recommend this model. Realize though that all smoke alarms are now designed to have a seven year life span. So know that in seven years all these units will have to be replaced with new ones.

Update: A little cooking accident caused a lot of smoke (no fire). The nearest alarm went off properly, and all of the linked alarms went off as well. Silencing the alarm required holding down the silence button for five seconds or so, which silenced all of the linked alarms.This review is based ONLY on the installation and setup.I just installed 7 units. The installation is very easy...took me about 60 seconds per unit to install the mounting rings.. You'll need a Phillips head screwdriver and a drill with a 3/16 bit for the mounting holes. I'm pretty handy with tools, but there was nothing involved in this that a novice should have difficulty with.Follow the instructions for where they should be mounted. There is a "dead zone" where walls and ceilings meet. Smoke detectors are ineffective in that zone. The previous owner of my home mounted all of the old detectors right in the dead zone. Oops.The programming is easy IF you read the directions and follow them exactly. Women should do fine; men will probably have to try programming a couple times before they figure out which simple step they overlooked. (I got it on the second attempt.) If you are overdue for new bifocals like I am, you might need a magnifying glass.The programming took less than a minute per unit when I did it correctly.Use hearing protection while you are programming and and testing. Seriously. All of the units will be going off at the same time on the table in front of you. At 85 decibels each, it is extremely loud,My total project time for installing all 7 was about 45 minutes hour from opening the box to putting up my tools.My units are spread out over three levels of the house (one in the basement, two on the first floor, one in an upstairs hallway, and one in each of three bedrooms). No issues with them communicating with each other. I tested each one individually and made certain it was communicating with all the others just to be sure. Running up and down all the stairs 7 times was a good workout. Again, hearing protection is advised. I have no doubt we will all be awakened if we ever have a fire in middle of the night.I really like the voice feature. If I have an alarm I will not have to go running through the house to figure out where the problem is. It clearly enunciates which unit is going off.Hopefully I will never find out how they operate in an emergency. I will update if I have any operational issues.

Great Product from a well trusted brand. Works exactly as expected with beeps and voice alerts as to location and warning type. Fits base of previous similar models.