Takes way more than an hour to warm my house up on a morning. I have it on about 2 hours on morning, then set back to 18 for the day so it doesn't get too cold before evening heating kicks in.
What's your flow temp set to on the boiler?
Are the rads all hot at the top? No trapped air.
You can get a radiator brush and clean the fins out on the back, helps to get more air through and more heat transfer to air.
The heating is set to 18°C for the hour in the morning shortest time period I can set it for) but, the way the Nest works, it pre-heats the home to ensure the house is at the set temp at the start of that period by learning over time how long it takes to heat the home to the required level from the current level e.g:
Set heat to 18°C for 06:30-07:30 and current internal temp is
14°C - it will switch the heating on at, say,
06:00 so that the house is 18°C at 06:30, then maintain this heat until 07:30 where I have set the temp to 10°C (while I am at work)
Set heat to 18°C for 06:30-07:30 and current internal temp is
10°C - it will switch the heating on at, say,
05:45 so that the house is 18°C at 06:30, then maintain this heat until 07:30 where I have set the temp to 10°C (while I am at work)
The same happens for the evening temp so, although I have the timer section of Nest set to a total of circa 6 hours of heating "on" Mon/Fri (all day Sat/Sun), it may operate for more due to the pre-heating function (I hope that makes sense)
Flow Temp is set to 55oC on a condensing boiler.
That is an amazingly well. Insulated house!
Unless I'm reading it gets really cold when it's off
I think you might be reading it wrong - the temps on the screenshots (18°C and 10°C) are what I have set the temps to at those times, not the actual room temps at the time. To give you an idea - the heating has been off for about 4 hours now and temp has only dropped from 18°C to 16.5°C with an external temp of 3°C (at work so using app to see temp).... I'll see how it goes later this afternoon
New build house so as insulated as you can get for a modern mass produced home.