Today I've been researching smoke detectors and CO monitors. A good half of them in my house have their doors hanging open to remind me to put a new battery in. I had to remove the batteries when the stupid things started beeping - usually starting at 3:00am. I am not totally without protection though - I've got nine of the things installed in my house. I went for overkill.
Things I have learned from experience and today's research:
Don't get ones with 9volt batteries in them. A two pack of 9v's in my grocery store runs $11.99!!! You can get them powered by AA batteries now - much cheaper and more common than the 9volt batteries.
Don't get the pure ionization ones. If you are going to get the single sensor type, get a photoelectric sensor. Better is to get the dual sensor models that have BOTH photoelectric and ionization.
Do read reviews to see which ones are more prone to false alarms. I came to the conclusion (from reading reviews) that the Kidde brand is more prone to false alarms than the First Alert brand.
I prefer a CO monitor that displays actual CO levels. Many don't display anything at all. Others have a few bars to indicate the level (like the signal strength bars on your cellphone). The best ones have a true numeric display, and can show both current levels and peak level detected since you last reset it.
For CO monitors, same recommendation as smoke detectors - get the AA powered ones, not the 9v powered ones.
I see no advantage to a 120v CO monitor, other than some of them can use wiring to link to other alarms (this is additional to the power wiring, but is included in many newer houses). This way, when one goes off, they all go off. To be useful, the unit needs to have a backup battery anyway. So why not just get a battery powered one in the first place (unless you have a newer home with the linking wiring already in place)? Then you can pop the CO monitor off the wall and take it with you on vacations to be safe in your hotel room. Smoke detectors are the same - I don't care about the 120v ones, but some of those support linking as well. Some even support "wireless linking".
You can get smoke detectors that run on sealed internal ten year lithium batteries. These are about double the cost of the AA battery ones. If you figure in the cost of AA batteries for ten years, the lithium ones come out to about 1-1/2 times the cost. But you never have to change the batteries. Since smoke detectors should be replaced every ten years anyway, why not get one that includes an internal battery that lasts for that entire ten years? The bump up in total cost comes to only a few dollars, which is worth it to me to keep from dragging ladders into the house to replace batteries every year (we have vaulted ceilings everywhere).
Here's what I think I have settled on (I'm still researching though, to make sure):
Photoelectric/Ionization smoke detector (for all living areas of the house):
First Alert model SA3210 (ten year lithium battery, $47)
https://www.amazon.com/dp/B011O2WVC...7YOOKUHO&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it
Photoelectric only smoke detector for non-living areas (basement, garage):
First Alert model PR710 (ten year lithium battery, $25)
https://www.amazon.com/dp/B00ON6M53...7YOOKUHO&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it
CO monitor (one each for upstairs, downstairs and basement, but none for mid-level that doesn't have bedrooms)
Kidde model KN-COPP-B-LPM (3xAA batteries, suggested yearly replacement, $23)
https://www.amazon.com/dp/B004Y6V5C...M7YOOKUHO&ref_=list_c_wl_lv_ov_lig_dp_it&th=1
Things I have learned from experience and today's research:
Don't get ones with 9volt batteries in them. A two pack of 9v's in my grocery store runs $11.99!!! You can get them powered by AA batteries now - much cheaper and more common than the 9volt batteries.
Don't get the pure ionization ones. If you are going to get the single sensor type, get a photoelectric sensor. Better is to get the dual sensor models that have BOTH photoelectric and ionization.
Do read reviews to see which ones are more prone to false alarms. I came to the conclusion (from reading reviews) that the Kidde brand is more prone to false alarms than the First Alert brand.
I prefer a CO monitor that displays actual CO levels. Many don't display anything at all. Others have a few bars to indicate the level (like the signal strength bars on your cellphone). The best ones have a true numeric display, and can show both current levels and peak level detected since you last reset it.
For CO monitors, same recommendation as smoke detectors - get the AA powered ones, not the 9v powered ones.
I see no advantage to a 120v CO monitor, other than some of them can use wiring to link to other alarms (this is additional to the power wiring, but is included in many newer houses). This way, when one goes off, they all go off. To be useful, the unit needs to have a backup battery anyway. So why not just get a battery powered one in the first place (unless you have a newer home with the linking wiring already in place)? Then you can pop the CO monitor off the wall and take it with you on vacations to be safe in your hotel room. Smoke detectors are the same - I don't care about the 120v ones, but some of those support linking as well. Some even support "wireless linking".
You can get smoke detectors that run on sealed internal ten year lithium batteries. These are about double the cost of the AA battery ones. If you figure in the cost of AA batteries for ten years, the lithium ones come out to about 1-1/2 times the cost. But you never have to change the batteries. Since smoke detectors should be replaced every ten years anyway, why not get one that includes an internal battery that lasts for that entire ten years? The bump up in total cost comes to only a few dollars, which is worth it to me to keep from dragging ladders into the house to replace batteries every year (we have vaulted ceilings everywhere).
Here's what I think I have settled on (I'm still researching though, to make sure):
Photoelectric/Ionization smoke detector (for all living areas of the house):
First Alert model SA3210 (ten year lithium battery, $47)
https://www.amazon.com/dp/B011O2WVC...7YOOKUHO&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it
Photoelectric only smoke detector for non-living areas (basement, garage):
First Alert model PR710 (ten year lithium battery, $25)
https://www.amazon.com/dp/B00ON6M53...7YOOKUHO&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it
CO monitor (one each for upstairs, downstairs and basement, but none for mid-level that doesn't have bedrooms)
Kidde model KN-COPP-B-LPM (3xAA batteries, suggested yearly replacement, $23)
https://www.amazon.com/dp/B004Y6V5C...M7YOOKUHO&ref_=list_c_wl_lv_ov_lig_dp_it&th=1
