3 ms·

What problem does adding hysteresis solve on a digital thermostat, though? Is it a problem that it stays closer to the asked temperature?

mjevans 5y ago
If you've ever had a basic electronics course with a raw button, hysteresis might instead be known as 'debounce' or making the button's single human action a single 'press' result on the other side. I think a digital thermostat could work well enough if they weren't made with a focus on being stupidly cheap or possibly somehow still absolutely energy efficient. * Wake up and respond FAST to user inputs. * Show the numbers it's thinking of big (running average over 5, 10, 15 min?), but also the current reading small (but readable) updated whenever it polls. * If there's a hold or timeout involved display that too, expose the user to the thought process, don't just be a nearly opaque box. * Be responsive in other ways. If I switch modes at the very least kill the old mode's 'calling' line right then, even if the new one gets a cooldown to prevent equipment issues.
- seszett 5y ago
  But none of this seems to need hysteresis for the actual activation/deactivation of heating depending on temperature readings? One reason I could see is to preserve the life of electromagnetic relays, but modern thermostats should use solid state relays. These points also seem to be solved for any somewhat modern (less than 15 years old?) run of the mill thermostat. Generally they always show the current reading and give the temperature setting only when you ask for it though, that's the only difference I see with what you want.
  - mjevans 5y ago
    The comment was something like 'walking by' disrupting the air at the thermostat and that alone being enough to turn the furnace on at that exact moment. A running average, but also making it clear to the user (both the value the unit is using for the decision and the current instant input) as well as a 'running average' over a given window address that specific comment. I added my own frustrations on top since they're also part of the larger 'dumb down the UI' and make the device frustrating.

mjevans 5y ago

If you've ever had a basic electronics course with a raw button, hysteresis might instead be known as 'debounce' or making the button's single human action a single 'press' result on the other side. I think a digital thermostat could work well enough if they weren't made with a focus on being stupidly cheap or possibly somehow still absolutely energy efficient. * Wake up and respond FAST to user inputs. * Show the numbers it's thinking of big (running average over 5, 10, 15 min?), but also the current reading small (but readable) updated whenever it polls. * If there's a hold or timeout involved display that too, expose the user to the thought process, don't just be a nearly opaque box. * Be responsive in other ways. If I switch modes at the very least kill the old mode's 'calling' line right then, even if the new one gets a cooldown to prevent equipment issues.

seszett 5y ago
But none of this seems to need hysteresis for the actual activation/deactivation of heating depending on temperature readings? One reason I could see is to preserve the life of electromagnetic relays, but modern thermostats should use solid state relays. These points also seem to be solved for any somewhat modern (less than 15 years old?) run of the mill thermostat. Generally they always show the current reading and give the temperature setting only when you ask for it though, that's the only difference I see with what you want.
- mjevans 5y ago
  The comment was something like 'walking by' disrupting the air at the thermostat and that alone being enough to turn the furnace on at that exact moment. A running average, but also making it clear to the user (both the value the unit is using for the decision and the current instant input) as well as a 'running average' over a given window address that specific comment. I added my own frustrations on top since they're also part of the larger 'dumb down the UI' and make the device frustrating.