Hmm, good point. Because it uses a triac, I had assumed (incorrectly)
that it works pretty much like a standard household dimmer.

I have the in-floor heat in my den set at 30C and when I started
typing this, my Aube thermostat was showing three wavy bars indicating
the floor was operating at 60 per cent capacity (and what I had
thought to be 540 watts, versus 900 watts). Oddly, the thermostat
will still cycle on and off because I can hear a loud "snap" when it
does this; in fact, it just clicked off seconds ago and I can see
there are now no bars shown on the display. In a few minutes, I
expect to hear it click back on.

I took a look at one of the manuals and it does clearly state the bars
indicate "the percentage of heating time required to maintain the
desired temperature", so that seems to suggest you are correct.

Source:
http://www.aubetech.com/manuel/2/TH108PLUS.pdf

Ah, sure enough, "snap" and we're back to three bars again.

Cheers,
Paul

On 12 Feb 2007 08:18:13 -0800, "dpb" wrote:

Looking at the product brochures at http://www.aubethermostats.com/,
they're switching thermostats, too, just w/ models as fast as 15-20
second cycle times and solid-state switching instead of mechanical
relays. They don't actually "modulate" output except in the sense of
averaging, same as the range controls.

To do otherwise would require a mechanism to waste the "extra" power
as a in a voltage-divider-type rheostat which would be quite
inefficient and require quite large power resistors or other sinks.
The mass of the burner element is made relatively large in electric
stoves to make the average temperature reasonably constant. Better
stoves control on higher frequency cycles and have better-designed
burners to minimize the thermal cycling -- my Mom used to claim she
could tell the difference between her stove and others in that
regard. Whether real or simply perceived I have no idea...