Gentex GN-503 Smoke & Carbon Monoxide Alarm, 120V Hardwired Interconnectable Photoelectric w/9V Battery Backup & T3 & T4 Horns (918-0005-002)

Hardwired smoke/carbon-monoxide alarm with 9V battery backup. Came with a Duracell 9V battery. Bought several to replace the old (and prone-to-chirp) ones that were originally installed in the house. Note that these are not designed for battery-only operation (fine/expected - just be aware).I got these because of all the reports of chirping and false alarms from the common brands (Kidde, First Alert, USI Electric). The Gentex products are typically slightly more expensive (they're also designed for commercial use), but the slight price premium is worth it to not be woken up in the middle of the night for no reason. I was also annoyed by the random "chirp" we'd get on the old detectors (not because of a weak battery - just because it felt like it - read the reviews). From reading around online, the Gentex products should not be prone to this problem because they're a bit higher quality. They are also "Assembled in the USA", for what that's worth.To install, I swapped out the mount plate and wiring harness from the old detectors (3 wires to a custom plug/harness using wire nuts - no big deal - plug comes with the detector). We had standard in-wall junction boxes already for the existing alarms (typical because they're hardwired), so the mounting was simple. Doing the whole house only took a couple hours.The GN-503's are combo smoke/carbon-monoxide detectors - I used these in the hallways on each floor as required by code. In the bedrooms, I installed the plain Gentex S1209 smoke detectors. Equally easy.The 503's and S1209's have a "tandem" connectivity wire that links with all the other detectors (so if one goes off they all go off). This is typical for modern smoke detectors. Our old ones had that too, making the swap out very easy. They can work stand-alone if that's what you want (i.e., no tandem) - just don't hook up that extra wire. That said, most building codes require them to be connected now.Note that you typically need to swap out ALL of your detectors to be the same brand and they all have to be on the same electrical circuit. (At least, that's my understanding.) Turn off the power to the detectors at the circuit breaker, remove all the old detectors, install all the new ones, turn power back on. Doesn't take long, but this methodology prevents the different brands from affecting each other. Also - it's not a big deal to replace all of them at the same time because they're typically the same age, and you need to replace them after 10 years anyway (modern ones will even start nuisance beeping at you once they "expire").The detector wiring plug actually has 4 wires on it, but you don't use one of them. The extra wire (the red/yellow one) is to connect to "legacy" Gentex detectors. If you're swapping out all of them, you'll use the brown/yellow wire for the tandem wire.They look nice and are a standard creamy white (not greenish as shown in the picture).For anybody wondering about the difference between the standard, the "F", and the "FF" versions, the ones with F's have extra relays for turning on another device when smoke/CO is detected (F is one relay, FF is two). E.g., a strobe light, external alarm, or a notification for your alarm system. For home use, you probably don't need them (maybe if your alarm system is wired to all the detectors). I think you can use the F/FF versions and just not hook up the extra devices if that's what you want, but since the F/FF ones are slightly more expensive it's a bit of a waste if you don't need that functionality.We bought through Amazon from JMAC. Fast shipping, and all of the detectors had VERY recent manufacturing dates (like, no more than a month old). Very happy with them and would buy from that company again.Time will tell, but the Gentex detectors very much seem like quality products. It's a shame they're not more well known.

I'm sick and tired of the Chinese crap that Kidde and First Alert are selling these days. Their garbage sends frequent false alarms and fails early. The reviews for NEST are scary. I don't think the NEST is quite perfected yet.Looking for an alternative to those brands, I came across Gentex. These appear to be made in the USA (Chicago) and they work great. There are no frills such as voice announcements or wireless bridging, but in my opinion this is a good thing because there are less things that can go wrong.

I purchased 9 of these a few years ago, but they all started one-by-one doing that horrible beep for end of life or for failure. Something happened one day where they all started smoking on all 3 floors at once, and we had to rip them down and throw them outside. Glad we were home to save the pets from the smoke.It’s not super easy to find electric interconnected smokes with a relay for the security system, so I bought another set of them. Nice features on it such as separate relays for CO and smoke, interconnect, battery backup, status LEDs, etc, just wish they were more reliable without frequent failures and the price is quite high as well.

These last just over five years. Apparently the CO detector portion has a limited life. We built a house a little more than 5 years ago and they all started failing within a few weeks of each other. The instructions discuss the limit and the need to replace the units. Other than this surprise (to me anyway) They are excellent.

Great product, but I found out this week that they only have a 5 year life span. A little pricey to have to replace every 5 years, but it keeps us safe and that is the most important. Easy to install and easy to check on a monthly basis.

Works as described. No false alarms with this one. Eventually will swap my others for these. Only down side is doesn't speak like other brands. You have to pay attention to the sound type and blinking pattern.

Ordered 2 GN-503's and 3 1209-F's ...... installed and when powered up the whole place was screaming alarms. Turn off AC power and check each one by battery. One of the 503's instantly went into full scream mode until you removed the battery. All 3 of the 1209's went into smoke alarm mode and could not be stopped without again, removing the batteries. Really? One out of 5 aren't defective? And I'm supposed to trust the family's life to them? Good lord.

It worked nicely with the existing Gentex 9000 series Smoke Detectors.