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My rented accommodation currently has no boiler control whatsoever: no timer or programmable unit. I need to control the heating at the boiler by either increasing or decreasing the flow temperature and turning it down low at night. I will be soon be fitting a smart control system (such as a Drayton Wiser).

My gas bill is completely off the charts. In 50 days, I used a total of 7,400kWh. I called British Gas and their first reaction was "it is impossible to use this much gas. You must have a faulty meter. We're sending an engineer to change the meter".

Now in my previous place, I had to do exactly the same thing as there was no boiler control. It was a little smaller (one bedroom / 20 square meters smaller). I had a (relatively) manageable gas bill. For the period of mid Nov 2018 to mid Mar 2019, my total gas consumption in the old place over a 120 day period was 6,700 kWh, which works out to 1,675 kWh / month. However this new place is consuming an average of 4,440 kWh per month, which is insane.

The house is on two floors: 3 bedrooms, one bathroom, a dressing room and a hallway on the top floor all have radiators. Only the radiator in the one bedroom and in the hallway is on. The one bedroom is unused and the doors are closed and I don't heat the master bedroom as I cannot sleep properly if the room is heated. The downstairs has a conservatory acting as a dining room, a living room, an office, a bathroom and a hallway with radiators. Radiators are on in all rooms except the bathroom.

All radiators except the hallway radiator, which has been configured as a bypass radiator, have either Drayton TRV4s or Honeywell TRVs fitted.

I work from home, so the heating is on around the clock: set to a low flow temperature of around 40 - 42 degrees when I sleep and a flow temperature of 50 - 55 degrees during the day depending on how cold it is outside. So essentially heating flow is around 40 - 42 for a period of 8 hours and 55 for a period of 16 hours.

Up until I received the gigantic gas bill, the radiator TRVs were set at 5. This warmed the house to a comfortable level, but was not excessively hot. Certainly on the ground floor there are not enough radiators: the conservatory one is underspecced and cannot get the temperature to above about 15 degrees when it is zero degrees outside. The hallway radiator is largish but covers the kitchen as well and is right next to the stairwell leading upstairs, so it has to work quite hard.

The entire house has double glazed windows in PVC frames (the previous house had no double glazing and sash windows) that are all sealed properly around the windows. The front door is adequately insulated and there are no draughts. Total floor space in the house is 165 square meters. Ceilings are average height for a UK house.

After this crazy gas bill, I've set all TRVs to 3 and in one case to 4. This has made a bit of a difference, but not much. However, the house feels cold most of the time and I need to wear jumpers, except in my office where the TRV is set to 4.

I've been tracking my gas consumption over the last few days. I've kept a running record of consumption over various periods of time, which is in the table below. I have an old analog gas meter that measures in cubic feet. I calculate the kWh used based on the exact calorific value that British Gas specifies on my bill.

The columns below show the date and time of the reading, the number of minutes and days in total since the last reading, the total kWh consumed since the last reading and then three columns that show what the theoretical hourly, daily and monthly consumption would be if the reading for this period of time were averaged out to hourly/daily/monthly periods.

Most of the lines in the table are mixed 42/55 degree heating flows. One or two are either entirely 42 or entirely 55 degree periods, such as the last two - they're commented on the right hand side


I did one test to max out the boiler which you see in line two of the table. I turned on all hot water taps and left it running for 7 minutes to see if the consumption exceeded the maximum rating of the boiler. It does, but not by a huge margin. The boiler is rated for hot water at 38 kWh and the calculated usage is a little over 40 for this period. I probably need to do the test for a bit longer than 7 minutes (like 15). So it may or may not be correct that the meter is over-reading. The data just is not definitive from this test.

My question for you all: based on the usage pattern I've described above, is this kind of insane gas consumption to be expected (literally 2.65x the consumption of my previous house)?

My previous place had a floor space of around 140 square meters as opposed to the 165 square meters here (with one less bedroom than this place). I'm running a total of 6 radiators here and in the previous place I had 7 radiators running. So I'd expect the gas usage to be of a similar order of magnitude, not well over double.

What do you guys think? Do I have a meter or possibly a boiler problem, or is this gas consumption to be expected based on my usage pattern?
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