Gas usage / cost - 3 storey 5 bed

oldskoo1

Recently moved in to an 8 year old 3 storey 5 bed and I've been taking some readings.

Last month with typical temps of 10c day and 3c night I've clocked up around £95 - £105 worth of gas usage.

I think this is 7-10 units a day, I will check this.

House has 20 rads, 3 floors with digital thermostat in hall on 24/7, but it runs at 18c morning and evening, 16c in day and 14c overnight.

Would you estimate this to be normal given the house and temps?

Scary to think it could double or tripple if the temps fall to -10 like a few years ago.

I'm asking to see if anyone has a similar house and I'm trying to figure out if our boiler is problematic. Showing some funny symptoms.

Thanks

Jo_Mc_2

Funny you should post this tonight. I'm in a 2 year old 3 storey, 5 bed house and have just received my latest gas bill tonight which I really need to look into.
At our previous house, a damp and draughty 90 year old semi, we had a combi boiler and we'd typically use around 25 units in the quarter from late July-late Oct and bills were really low yet over the same quarter in this supposedly energy efficient new build we've used 144 units, giving us a £100 bill when all radiators have been switched off since late May, and last year wasn't much different.
I can see that we're using nowhere near as much as you but it still seems quite excessive.

macman

Without knowing the actual consumption, it's impossible to comment. Quoting ££'s spent tell us nothing about actual usage.
Post your units used and whether your meter is metric or imperial (or better still post kWh usage).
Running the CH overnight is completely unnecessary and will massively increase your consumption, especially on a system with 20 rads.

good_advice

20 radiators!!!! That is a lot.
My semi has 7.

oldskoo1

I have just done a reading for the last 24 hours in which we used :

9 Units
100.99 KWh

macman

That's a large amount, but a reading over just one day is hardly meaningful; you need to do at least a month once the heating is on to get a meaningful figure.
£3.50 per day in the autumn/winter is not that high for such a large system as yours (about £100 per month). Of course your annual spend will be much lower than £1200, because it will reduce hugely in the summer with the CH off.
Do you really need all 20 rads on though? TRV's? Fit some zone controls?

oldskoo1

We do have TRV's fitted to 80% of the rads.

I know you said £'s is no accurate measure but for example - when the CH was off, we used on average £0.65p of gas per day. Around £18 - £20 per month.

£80 extra now the CH is on just feels like a huge increase in weather that isn't too bad, typically 2c night, 8c day.

My only concern is the boiler might be playing up. It seems to cut out. I.e. starts up, runs for 8mins - 12 mins, stops for 1min then comes on again. After the first initial hit of gas and heat it only stays on for about 2 - 3mins before cutting off for 1min. Not sure if this is normal for my boiler (maybe it's programmed this way for efficiency) or it is causing the high usage (thought boilers are most efficient running at full whack). I expected it to just stay on until the thermostat temp is reached.

Had it serviced and new ignition fitted just a couple of weeks ago.

macman

It's quite normal to use 80% of your annual gas total kWh in the coldest 3 months.
Since prices have risen, you can't compare-what matters is your comparative kWh consumption.
The less the boiler is on, the less it's costing you.

oldskoo1

ok thats good, i assumed the boiler constantly tripping on and off every 2 mins would cause a lot of wastage as it does this for up to an hour trying to heat the house just a few degrees.

I recently fitted a digital thermostat and i think that might be contributing to the gas rise too. It seems to let it drop the temp too much then blast it about 2 degrees beyond whats needed.

Think i will refit the old turn dial and put it back on timed at the programmer.

oldskoo1

oh and also this house doesn't have cavity filled walls.

It's inner walls including room partitions are thermalite blocks leaving the cavity empty for air flow.

spinningsheep

What boiler is it? Need to know make and model, condensing or non?if the boiler runs for no more than 10 mins and then shuts off and relights for a few mins, then shuts off and so on, this is what's known as cycling, sounds like either the boiler temp is set too low and the system is reaching this temp very fast and so shuts down, or, the radiators cannot shift the heat being created and so the boiler is shutting down very fast.