On Saturday, April 7, 2018 at 8:07:19 AM UTC-4, wrote:
trader_4:

Sounds like H-Well went cheapo post-mercury
bulb jobs. Offering just a few presets in the form
either of dip-switches or 3 menu choices of #
of firings per hour.

With the old heat-insemenator-antessimator
GOL-DANGIT - Anticipators(!), like on the
mechanical HW setback formerly in my parents
place, if one knew what they were doing,
they'd measure the voltage to set the
anticipator by, and could get the temperature
swing to less than one degree F° above or
below desired set point.(as long as the thing
was mounted perfectly level on a wall near
no drafts)

IDK exactly how much my HW fluctuates by, but it's not perceptable
and the display always shows whatever it's set to, once it attains
that temp. I don't see how it can have anything to do with the
cost of the thermostat, it's just an algorithm in software. I would
think it was probably to reduce energy usage, ie by not having
the system cycle excessively. But then part of it I don't understand.
The number of cycles you get if you set it for a new, high efficiency
furnace is less than if you set it for an old one. You'd think it
would be the other way around, ie that an old furnace has more mass,
takes longer to warm up, so it would be better to cycle that one
less than a new system.

And as I pointed out, I don't think you could get his 6 deg swing example
with one of his old type thermostats either.