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Nest Heat Pump Max Saving not respecting/Learning Max Duration

Community Member

Hi there. 

It does not seem that Nest is learning or using the Max Duration setting (which I have set to 5 hrs) for my heat pump.  I have it set to be 23c by 6am.  However, it only starts at 4am. It does not get to the desired temperature in time, and therefore switches to stage 2 heating, and then AUX.

My expectation is that thermostat would learn and gradually start earlier so that it used only the heat pump, whenever possible, to achieve 23c at 6am.

On my main floor, I have a separate thermostat, that runs a separate heat pump, set to 23c all day, and it uses the heat pump almost exclusively. I just want to have it cooler at night on the bedroom floor so that we can sleep better at night.

See my settings, history and schedule below.  What am I missing?




Community Member


Nest Support team, any suggestions?  Is there some kind of "earliest preheat time" setting that is causing the 4am? Or is there a bug that causes the 5hr setting to be ignored, and set to 2 hours?

Community Member

Did you have your answer?

I've just installed a new heat pump system and I'm in a similar situation. Pre heat duration at 5h hours and it starts the aux heat too soon.

Do we have to set Early On to ON to make it work?

@TAG - no, nobody ever came to help out on this. I had experimented with Early On to ON as well as OFF and it made no difference.  I ended up trying to set a complex schedule to try to beat Nest's algorithms, but it totally misses the point of having this automation.