Minimum Overnight Room Temperature

sandy700

If I have my heating on from 08:00 till 23:00 with the thermostat set at 21 deg C and then the temperature drops to 16 deg C by 08:00 and use 50 kWh of gas to raise and maintain the temperature at 21 deg C until 23:00, will I use more gas if I switch off the heating at 22:00 and the temperature drops to 14 deg C by 08:00?

Which means that the heating has to raise the temperature another 2 deg C for the sake of it being off for 1 hour extra at night.

FreeBear

sandy700 said: will I use more gas if I switch off the heating at 22:00 and the temperature drops to 14 deg C by 08:00?

What you use by heating that couple of degrees in the morning, you'll save by switching the off an hour earlier. If you really want to make a saving on gas (and money) is to turn the thermostat down to 20°C or even 19°C and turn the TRVs down in rooms that are not in use.

BUFF

sandy700 said:

If I have my heating on from 08:00 till 23:00 with the thermostat set at 21 deg C and then the temperature drops to 16 deg C by 08:00 and use 50 kWh of gas to raise and maintain the temperature at 21 deg C until 23:00, will I use more gas if I switch off the heating at 22:00 and the temperature drops to 14 deg C by 08:00?

Which means that the heating has to raise the temperature another 2 deg C for the sake of it being off for 1 hour extra at night.

So, it currently drops 5C over 9 hours or 0.55C/h.
Why do you think that if you switch the heating off 1 hour earlier it will drop an extra 2C rather than another 0.55C (yes, it's a simplification but the order of difference that you are proposing is far higher than the likely error)?

FreeBear's advice is sound. 

Chrysalis

sandy700 said:

If I have my heating on from 08:00 till 23:00 with the thermostat set at 21 deg C and then the temperature drops to 16 deg C by 08:00 and use 50 kWh of gas to raise and maintain the temperature at 21 deg C until 23:00, will I use more gas if I switch off the heating at 22:00 and the temperature drops to 14 deg C by 08:00?

Which means that the heating has to raise the temperature another 2 deg C for the sake of it being off for 1 hour extra at night.

21C seems very high, I would aim for a drop to at least 18C, but not all at once as it might be too much of a shock to you, first drop to 20C, then when you used to it, go to 19C, and then finally to 18C.  I would also consider turning off heating for rooms you dont use.

What_time_is_it

My minimum overnight room temperature last night was about 30!

sandy700

Chrysalis said:

21C seems very high, I would aim for a drop to at least 18C, but not all at once as it might be too much of a shock to you, first drop to 20C, then when you used to it, go to 19C, and then finally to 18C.  I would also consider turning off heating for rooms you dont use.

Not if you are in your late 70's it isn't.

markin

sandy700 said:

Chrysalis said:

21C seems very high, I would aim for a drop to at least 18C, but not all at once as it might be too much of a shock to you, first drop to 20C, then when you used to it, go to 19C, and then finally to 18C.  I would also consider turning off heating for rooms you dont use.

Not if you are in your late 70's it isn't.

The key is fitting TRV's or just using them so that rooms you don't use can be 16c while rooms you do use are 21c.

Alnat1

16C for not in use? Seems very excessive to me unless it's a very damp house.

Chrysalis

sandy700 said:

Chrysalis said:

21C seems very high, I would aim for a drop to at least 18C, but not all at once as it might be too much of a shock to you, first drop to 20C, then when you used to it, go to 19C, and then finally to 18C.  I would also consider turning off heating for rooms you dont use.

Not if you are in your late 70's it isn't.

I would then just consider changes for rooms you dont use.