On Feb 4, 2:03*am, Edward Reid
wrote:
I have two smoke detectors in my house which are over 8 years old,
plus one CO detector. Since the smoke detectors are near end of life,
I'd like to improve the coverage. I also need new detectors in a
mobile home that I rent out.

My ideal would be

-- tri-mode (photoelectric + ionization + carbon monoxide)
-- interconnected (all sound when one trips)
-- operate whether power is on or off
-- loud

I realize that I probably can't have it all, so I'm looking for the
best compromise. I haven't found any place with really comprehensive
listings, especially any which make it easy to determine what models
meet which of my criteria. Consumer Reports has good descriptions of
the issues but analyzes very few models.

So I'm looking for advice both on what compromises are most
reasonable, and on specific models (possibly multiple models in
combination) which might implement that compromise. I appreciate
resources as well as direct information.

Notes on each of my items:

I probably don't need to explain why I want tri-mode -- anyone not
familiar with the types can easily google them. I'm willing to spring
for multiple detectors if there are no satisfactory tri-mode detectors
available. (I haven't found any tri-mode detectors in a single unit.)

The advantage of interconnection should be obvious. Same for loud.

I'm unsure whether I want AC powered or battery powered. AC powered
work without needing to change batteries and have plenty of power for
a loud alarm. Battery powered operate when the power is out; I don't
know if any of these can be interconnected. I know there are some AC
powered with battery backup, but then that's still a battery to
monitor and replace.

The big question with respect to AC vs battery is which is more
effective overall. Power isn't out very much, but it does go out. In
the house it probably averages a few hours a year -- once it was out
for 18 hours after a severe thunderstorm, but usually it's not more
than an hour or two, and it goes for months with no interruption at
all. The mobile home is in a rural area and outages can be longer; it
was without power for 3-1/2 days after Hurricane Kate, about 25 years
ago. But are there any common factors to fire and power outage?
Anything about a power outage that makes fire more likely? (Using
candles and kerosene lamps would seem a significant risk. I have
battery operated lights instead.) Perhaps an electrical malfunction
could start a fire but then trip the breaker powering the detectors
before they sound the alarm? On the other side, weak batteries are an
obvious risk, albeit one which regular testing ameliorates. So neither
is perfect, but what are the probabilities of a multiple failure? That
is, power outage plus fire, or battery failure plus fire, or alarm not
loud enough plus fire, etc? Are there other common mode failures?

In the house, I can easily run AC wiring and/or interconnection wiring
in the attic. In the mobile home, I might be able to run it above the
ceiling, or I could gouge a trough in the ceiling tile or just run it
along the upper corners -- the place doesn't look good enough for me
to worry about the damage.

Edward

Get at least the AC/DC in your rental. If you only get the battery
operated ones, the renters will take the batteries out to use in some
gadget.

Hank