12 Pack Bundle of USI Electric Hardwired Ionization Smoke and Fire Alarm with Battery Backup (5304)

I bought 8 of these to replace some old USI 5204. Unless you love troubleshooting random issues and being driven to insanity in the middle of the night, I can't recommend any USI product. During a remodel, my contractor installed 8 interconnected model 5204 (the version prior to this product). 2 of the 8 would chirp randomly and for no apparent reason--and only at 3am, naturally. I changed batteries in them 3-4 times per year as a result and even installed new model 5204. After changing the 2 bad ones, the problem persisted in 1 of the 8 units with another one that would go full alarm whenever anyone walked by generating static (dragging a blanket along the carpet, for example, even a floor above!). Imagine your kid dragging a favorite blankey to bed and getting the daylights scared out of them for it. Finally after a decade I decided to replace them all (the USI 5204, not the blankets or kids). I so much wanted to get anything other than USI. But I did not want to redo the electrical connectors. So I was sucked in by the promise that the 5304 could use the same wiring connectors as the 5204. And I figured, "It's been a decade--they must have gotten all the bugs worked out by now." Oh how I was to be greatly disappointed! I removed the 8 old ones and installed a new 5304 with no problem. But whenever I added another 5304 to the system, they would all go full alarm the moment I plugged them in and could not be silenced without disconnecting them. I gave up trying to figure this out after my dogs, wife, and kids couldn't take it anymore and threatened to go live in a hotel. After some research, I think the 5304 must have new connectors--not the same ones as the 5204. This is baffling because from an electrical standpoint, there appears to be absolutely no difference. And I figured as long as I have to rewire, I might as well switch brands, because let me tell you, by this point I had developed a complete hatred for USI products after a decade of terrible performance. Even now when I hear a bird chirp outside, my first instinct is to start hurling 9v batteries at it wildly in a misguided attempt at self defense. And I always carry several 9v batteries in my pocket now, to be ready to install in a USI product anytime. So after all this trauma, I installed Kidde with new connectors. It was way easier than I thought. Goodbye USI and good riddance.

Bought eight of this unit and a few of the ones with CO detection as replacements for the original builders' USI units as I noted they were more than 10 years old. I like that these use the same wiring harness as the originals, so installing these in the exact same locations was straightforward. HOWEVER, from the beginning (July 2014) they were giving me false alarms whereas the originals they replaced did not. Battery replacements didn't fix it. They are interconnected as per code, so when one tripped they all go off and its really annoying to check them all looking for the one that was "first out". They promote a feature that is supposed to help you determine which one caused the trip, but I never got that to work - the "find" feature just made them all go off at once again. My poor dogs are terrified of these things. The problem gradually got worse and worse, to the point that the only way to make the random trips stop was to pull the offending unit down. I have only 3 left on the ceiling (and lots of dangling wires) and I am looking for a replacement that isn't made by USI. I was just looking at the Amazon description for this model and it says 3-year warranty for these units (most others are listed as 10 years) - Surprise! the manufacturing date on the back of the units is December 31, 2012, so technically they outlasted the warranty period. Consumer reports recommends Kidde and First Alert brands - and oddly, no USI models - so I will be looking at those for replacements...

My mother's model 5204 needed to be replaced. I checked at Lowe's but they don't carry the USI brand. Interestingly enough, the fireman said any wired, 3 prong detector would work with her household system. According to Lowe's, that is incorrect. You should buy the same brand to guarantee they will all sync together.This unit, while looking slightly different than the 5204, worked perfectly with the existing wiring plug and mounting bracket. It came with a 9-volt with the plastic tab for removal; however, I replaced that with a brand new, higher-end 9 volt.Simple and easy.

This model (#5304) was a plug-compatible replacement for the earlier model (#5204) which meant that I did not need to rewire the units. Just unplug the older model and plug-in the new one. Very pleased about the ease of replacement.Most people are aware of the fact that detectors do not last forever. The instructional pamphlets alert users to this fact, and expiration dates are projected forward from the branded manufacture date. All detectors that I’ve used have had a post-manufacture, nominal 10-year life span. Yet, in practice it is always less. Why is this true? Because there is a lag between manufacture date and sale to customer date. This gap means that in principle a detector usually has less than a full, 10-year lifespan—which is reasonable. And a small gap is to be expected by any purchaser.My complaint has to do with the life span of the units I received. The two detectors were obtained during November 2017 and had a manufacture date of July 2016 which means that both have an effective life-span of 16-17 months less than ten years. I expect this diminished life because both of the replaced USI units stopped working within one month of their projected, 10-year lifespan. That is close!Purchasers may be expecting, incorrectly, a ten-year use beginning from the actual first day of use. It does not. Vendor transparency requires a cautionary disclaimer to notify customers that they are selling “dated” units with considerably shorter lifespans.

I have had to replace two of these in the past two years, despite them being only two years old. The warranty is 10 years, but what they fail to be clear about is, you have to pay return postage, AND include a check for S&H to the value of $5. Total cost to you? around $10. New one bought off Amazon ... $11. The reliability is not good and the house is full of them, all intermeshed so I cannot easily switch.