Heating start time

[david]

I want to have at 7h in the morning a temperature of 21°. At night, the heating only switches on when it is colder than 16°. Does anyone have an idea how to calculate the optimal start time for the heating? This is to have exactly 21° at 7h.The goal is not to have cold in the morning and also not to start to early with heating and wasting energy.
Thanks.

[kenzo]

This depends on so many variables which are only known to you that I believe it's impossible to provide you with answers.
- what's the flow temperature? Do you want to change that as well?
- what kind of house is it? (stone/wood/etc.)
- how big is the house?
etc.
My approach would be to simply test it - try start heating at 6am, when do you finally reach 21°C?
Plus, does it make sense to go to 16°C at all?

[shooter]

There is a block for this, the essence of it, is measure the real temp at 6 oclock. If the temp is 16 and your slope is 5 degrees/hour start heating now.
If temp is 17 start heating at 4/5 so about 6:15 etc.
As the slope must be measured just start at 6 and check when 21 is reached. this will be your slope.
remember to set max watertemp on the boiler as this will influence the time cosiderate.