Tim Fischer wrote:
"Pat" wrote in message
oups.com...
Hey, if it saves 10%, buy 10 of them and you have free heat, won't
you???

OK I know that was meant to be facetious, but as a former math major this
type of logic bugs me. You see it all the time, like on Leno's headlines --
the ad says "50% off, then take an ADDITIONAL 50% off..." Leno chuckles
"must be free, hey what a deal!"

Wrong.

50% off of 50% off is 25% of the original, not 0%.

And 10% off 10 times in a row is about 35% of the original value, not 0%.
And that's of course assuming that the effect is stackable, which of course
it probably isn't.

Carry on, just being geeky...
-Tim

I see your geekiness and raise you their absurdity. Their web site
say: " it's guaranteed to reduce heating fuel consumption by at least
10%! Beckett HeatManager™ boiler controls improve the efficiency of
most gas, oil, or propane-fired residential boiler home heating
systems"

So if it only improves efficiency in 'most' systems, then ....