On 2/4/2018 3:29 PM, Cindy Hamilton wrote:
....
I've never understood the "precision" argument. Does it matter whether
it's 70, 71, or 72 F ? I suppose 31, 32, and 33 F are more significant.
....
Well, there's the same question around 212, too, from that standpoint...
I ran into a minor instance here just recently -- fixed up a monitoring
system in the well house to alert me if the temperature drops that
indicates I need to go relight the gas heater (occasionally the high KS
wind will manage to blow out the pilot). I used a cute little $6
digital thermostat module in "heat" mode to turn on an LED in the window
I can see if temp drops below setpoint.
I just stuck the RTD sensor inside the small project box I mounted the
controller in and velcro-ed it to the wall near the power outlet on the
plywood backer board for the electrical panel, etc. Since the block
building walls aren't insulated, it gets pretty cool right on the wall
surface so wasn't sure where would need to set the setpoint to not false
alarm on really cold days even though the little heater keeps the bulk
air temperature around 50F. Started at 5C -- 41F and we had some
bitter nights shortly thereafter and it triggered. So, not wanting to
try to cut it too close, 1F is ~0.5F so lowered it to 4.5F and added
3/4" of foam packing between the solid wood board mount and the unit.
So far, it's not triggered again but it's not been below zero again
since, either; we'll just "hide and watch" and see how it goes.
But, long-winded that got me wondering; are European
thermostats/thermometers registering tenths or are they using 1C
setpoint tolerances? I can tell difference in our house between a 69F
where we normally keep for winter and 70F setpoint; there's a
significant run-time difference as well so if it were 20C or 21C that
were the choices, the 20C -- 68F is notably chilly and so 70F would be
next best granularity could get and that would, over time, be observable
in heating bills.
Not huge, but "yes, I think it can make a difference" in ordinary things...
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