On Wed, 19 Nov 2008 21:44:40 -0600, "HeyBub"
wrote:

Vic Smith wrote:

Congratulations, you've just saved yourself 25 cents a year in
electricity.
Not to mention it might not be safe if someone is standing on wet
pavement and they gey shocked by 120V.

Geeze, I replaced the transformer powered doorbell in my house 10
years ago with a 15 buck wireless chimer. Couple screws and it's
done. Replaced the AAA batteries once in all that time.


$15 at 25c/year means you'll recover your costs in 60 years. But the
batteries cost, oh, $1.00 every ten years, so that's another six bucks which
will take another 12 years to recover. But 12 years means one more set of
batteries, which requires another four years. Let's see, now (mumble,
mumble, carry-the-three), ah, yes.

Your wireless solution will save you money after a mere 73 years of service.
This does not count lost opportunity costs of the original $15.

Delete from that cost the cost of repairing/replacing whatever was
wrong with the original system (cost of transformer, button, chime and
wire plus labour to replace)

He might still be saving money.