I need to install more smoke detectors

[Admiral]

I got years from a 9V, since what I have is line voltage powered, and the battery is only a backup in case of power outage.

Hardwired units are still available, I replaced all of mine after 12 years or so; you have to rewire for a new type of connector, but no big deal.

[K. L. McReynolds]

Locally, only the 10 year type detectors are installed by the FD/Red Cross/other groups. And they print on the outside the replacement date with indelible markers.

[EricU]

Are those battery power with no hardwired connectors?  I want to avoid radios.

[daddo]

Was working on a rental home for an owner and heard the smoke alarm doing the low battery beep. I told the tenant I'd let the owner know it needs a battery. The tenant said; "That's ok, they don't work anyways- I smoked in here once and it never went off."  

[Snipe Hunter]

The 9v units are no longer available in MD. 10 year lithium "Sealed" only and they need to be Carbon Monoxide/Smoke detectors. Every bedroom, hallway and stairwell.

From what I understand, the 10 year battery units will give you a tone when the batteries start dying or at 10 years, whichever comes first.

Here's some on Amazon Link

Some fire departments will give them to you.

[EricU]

I wonder if those leds would be bothersome in a bedroom. I think if it's properly on, the led is on and green

[TDKPE]

I wonder if those leds would be bothersome in a bedroom. I think if it's properly on, the led is on and green

My hardwired units have a green LED that's on when the power is on, and they don't bother anyone.  Hardly noticeable.