One product I am looking into is First Alert SA320CN Dual Sensor Battery-Powered Smoke and Fire Alarm. It has a lot of reviews, mostly positive. And while this is not a review per se, it covers the safety issue perfectly, Firstinlastout wrote, "As a professsional firefighter/paramedic for nearly 13 years, I see a lot of fires. I do know that most detectors out there are NOT dual sensor....they are mostly only ionization detectors that detect flame. Remember it's usually not the fire that will kill you, it's the smoke and it's deadly component carbon monoxide that will end your life. Photoelectric detectors detect these smoke particles and alert you.......ionization types rarely do if it's a slow smoldering fire. If your sleeping, by the time the ionization sensors detect the actual flames, the smoke and the CO will most likely have already gotten to you and you will be dead.
That's why it's so VERY VERY important to have a dual-sensor smoke detector. This item particular item IS a dual sensor that is designed to alert you to both smoldering low-flame fires and high intensity/ rapid flame fires. This detector will protect you 100% from fire related death/injury if used properly and placed correctly in your home. Remember to replace the battery every time you switch the clock during daylight savings time or any time the detector chirps. Always look for a photoelectric/ionization detector and buy one. Have one in your hallway, in the main living room at the very least and I always like to put one in each room because I am overly cautious. Also make sure to have a B-C extinguisher on hand near the kitchen to put out kitchen grease fires....the #1 cause of residential structure fires. Hopefully you can put a small one out, but if you discharge the entire extinguisher and the fire is not out......evacuate the house immediately and make sure you or someone called 911 prior to exiting your home. Stay safe !"
In Washington I found some ten year lithium battery stand alone dedicated CO2 detectors. After reading that post, I think I will get a couple more.
I agree that dual sensor is important and there is more than one way to do it. Nest has a white paper that makes several points, "Since residential smoke alarms were first popularized in the 1970s, home fires have changed: while it would generally take up to 30 minutes for a fire to take over a room in the 1970s, it can take as little as 5 minutes today. Today’s homes are bigger, with more open floor plans, more composite construction materials, and more polyurethane and synthetic furnishings which burn faster than materials used decades ago."
The First Alert SA320CN Dual Sensor Battery-Powered Smoke and Fire Alarm is reasonably priced and is the best seller on Amazon, which means it has been extensively reviewed. It can be installed standalone, it does not have CO2 detect, but I am willing to consider separate systems. A plus many people mentioned in the reviews is the ease of changing the battery which is a definite plus. I think I will ship a couple to Hawaii and we can see if they are relatively trouble free.
One of the products I have been reading about is Nest. One of my Facebook friends has had the same problem I have had with smoke alarms, Kip wrote, "Sounds like our nest smoke alarms. Lots of false alarms and had to take them down for sanity. Those ones talk to you and as I was trying to silence the false alarm at 3 in the morning the nest alarm was saying this alarm can not be silenced. I said yes you can and took them all off the wall, threw them in a bucket and put the lid on then took it out to the garage. That was months ago and when I go into the garage they still beep at me from the bucket. They may substitute for clay pigeons next."
I am duly warned. Our house may not be ideal for the Nest. The Protect does interconnects wirelessly using a self-created wireless network so it works independently of your own Wi-Fi even if power fails. However, we can't cover the whole house with a single wireless network because the office is over the garages and separated from the house by a large lanai.
Another feature is interaction w/ the thermostat. The Nest has the ability to turn off the HVAC in an emergency so it doesn't fan the flames.
And it has a phone App. I am not a big App person, but when we are in Hawaii it is great to be able to see what is going on in Washington. I just ordered one and will see how challenging it is to set up and operate.