Posted this on another recent thread.
We have 3 thermostats. One in the open plan downstairs area which controls the underfloor heating (gas not electric), one in the hallway downstairs and one in the hallway upstairs. The 2 hallway ones are Nest ones.
Upstairs is set to 15°C, downstairs is set to 16°C and the underfloor one is normally set to 16°C, but this week we've turned it up to 18°C.
The downstairs Nest one also has a set time to come on for 1½ hrs in the early morning (40 mins before we get up). This is set for 2 hrs later on the weekend. This temp is set to 19°C.
This thermostat is also set to come on for 2 hrs at night, to 20°C, and comes on around 9pm, so that it's warm when we go to bed.
If it wasn't for our downstairs bedroom being considerably colder (5+°C less) than the rest of the downstairs, 9 times out of 10 we wouldn't need to have it on at all at night.
We added underfloor insulation last year, but it's not made much different, tbh, and this is one of the only 2 rooms left from the original house.
The other is the entrance hallway, which is also usually quite cold.
They both have earth floors/foundations with raised joists and a wooden floor. We've added good underlay and carpet, and added 100mm celotex directly under the floorboards in our bedroom last year, but I think our next step will be to add cavity insulation as well to completely fill the spaces of both areas.
The downstairs Nest is located just beyond the cold entrance hall, on the other side of an internal door. During the day, it's set to 16°C, which it almost never reaches, and even at night it's rare for it to drop to 16°C.
Upstairs isn't used atm, so it's set to 15°C all the time, but once dc are home, that will be set at 20°C for 2hrs early morning and again for 3hrs between 8pm and 11pm. It will also then revert back to its minimum temp.
Once dc is home this minimum temp will be set to 17°C during the day and 16°C between midnight and 6am. When the outside temps are 1°C or less, our upstairs does drop below the minimum temp of 15°C, and so will switch on as needed.
This usually means it may be on for a max of 2/24hrs spread out over the 24hr period.
Once upstairs is being lived in, it generally doesn't drop below 16°C, except maybe overnight in severely cold weather.
The open plan underfloor hearing is normally set to 16°C overnight, but this last week it's been set to 18°C, which it does reach at some point.
During the evening, say from around 7-8pm it is raised to 20°C, and this is lowered back to 18°C when we go to bed.
We have gch.
Our gas bill is already ridiculously high, and we're not even heating upstairs yet.
The Nest heating is on for 5hrs/24 in total (looking at the history) and the underfloor is on for abt 3hrs per day and our gas usage is already hitting £7-8/day.
Last winter, our gas and electric was costing us £100 per week. It is scary, really.
I'm actually very naturally energy-saving conscious, so I dread to think what our house would cost most people!