Nest thermostat increasing energy bill

sxp842

FreeBear said:

Got any TRVs on the radiator nearest the thermostat ?

If so, the TRV could be shutting the radiator off before the room is up to the temperature the thermostat is expecting.

Yes, we do. I thought the answer to that was to keep the TRV in the same room as the thermostat turned up to full. But would it be worth replacing the radiator valve instead?

Tallerdave

Has consumption gone up,or did the price increase, or is your IHD rubbish? You need to compare meter readings over time. 

coffeehound

sxp842 said:

We then eventually moved into our flat in September 2020. However, we only just got a nest thermostat installed 2 weeks ago. Prior to this we were just controlling the temperature on the boiler and radiators.

Hi.  Were you previously turning down the flow temperature on the boiler?  Is it set higher now?

If you kept the flow temperature lower in the past and water was returning to the boiler well below ~55 ℃, then the boiler would have been operating in "full condensing mode" which gives the highest efficiency.

If you now have the radiator circuit temperature dial set higher, then it will run at a lower overall efficiency.

Gerry1

You shouldn't be relying on the ££ figures from the smart meter for several reasons.

• It may not have been programmed correctly all the time, e.g. if it was working correctly and went dumb, or vice versa.
• The cost per day probably includes the standing charge which may have increased if a fixed tariff has ended or a variable tariff has increased.
• Similarly, the cost per kWh may have increased.

Far better to read the meter on the wall and record the volume (m3) readings.  Ideally convert it to kWh using the latest Calorific Value then multiply by the cost per kWh.

Most people switch the boiler off overnight so that would be a good place to start.

cannugec5

We have a nest. Love it. The daytime temperature is set at 18-20, with night time at 11. 

You have to remember the Nest is very clever. If I want to get up to a warm house at 7am, I set the temperature for 7am, and the thermostat will switch on at the appropriate time, according to the weather, to reach my desired temperature at 7am. None of this setting it an hour ahead anymore. 

Anunnaki

cannugec5 said:

We have a nest. Love it. The daytime temperature is set at 18-20, with night time at 11. 

You have to remember the Nest is very clever. If I want to get up to a warm house at 7am, I set the temperature for 7am, and the thermostat will switch on at the appropriate time, according to the weather, to reach my desired temperature at 7am. None of this setting it an hour ahead anymore. 

Same here: Weekdays heating/hotwater set to come on at 17:00 hrs off at 21:00hrs  4hrs      "starts earlier to get to temp up at that time. 18° 

Night time setting 9°

Weekends set at 20°same times. But if in override with dial depending on weather etc.

Use the mobile phone function to detect when people are in house at other times so its not heating empty house. Holidays? etc

Sometimes loses connection though?