Gas boiler kwh usage 3 January at 4:30PM edited 4 January at 10:27AM in Energy 9 replies 227 views

Chickenmum

We have a potterton suprima boiler 18 years old recently serviced by British gas who said its still 78% effective 

Our home is 160 year old 5 bed Victorian house high ceilings but new double glazing 

We have always had high gas bills in the 17 years we have lived here but the current price increase has made us more aware and on our recent bill we are estimated at 42000 kwh for next year where average 4 to 5 bed appear to be 17000 
We only have heating on from 5am until 8am then 5pm until 830pm and 3 bedrooms have radiators turned off
HW tank is heated for an hour daily 5pm to 6pm 
Does that seem reasonable usage as it seems excessive to me and don't know if meter being faulty is a thing 
Since 4th Dec until today 3 Jan meter reading is 556 units ...have been at home more this past month with Christmas holidays 
Does anyone know how I would get meter checked?

Chickenmum

Just ran the boiler for an hour and the meter went from 38610 to 38615 

BUFF

As someone who lives in a 3-bed Edwardian terrace it doesn't seem impossible to me but it's obviously high by comparison to a modern building. Is it detached, semi-detached, terraced?

new dg is obviously good compared to what it will have been built with & hopefully will diminish your heating demand by some amount, what other fabric upgrades have been done?.
roof spaces insulated?
do you have a room 'stat & TRVs?
what room temp(s) are you heating to?

If you truly are using 42,000kWh/annum & your Suprima is still 79% efficient (did BG give you a printout?) after 18 years then I wouldn't be surprised if you could save ~8,000kWh/annum by upgrading boiler & controls but that obviously comes at an upfront cost. If the Suprima has lost efficiency and/or you make behavioural changes you might possibly save even more.

FreeBear

Check to see if your gas meter is metric or imperial, and then check to see if you are being billed for the correct units.

I had a supplier billing me for (100s) cubic feet when my meter was reading cubic metres. Took a change of supplier to get it sorted.

Chickenmum

Thanks but meter is m3 and bill looks to have correct calculation..the bill I had was 525 units converted to 5906 kwh 

matelodave

You really should be doing some monitoring of your own rather than either waiting for the gas bill or assuming that the annual estimate is anywhere near close. Dont forget that December was a fair bit colder this year than last and like a lot of people you said you were at home for longer than usual because of the holidays.

Getting panicked over a month which isn't actually representative of your normal consumption wont help you save money if you decide that it's the criterion for lashing out several grand on a replacement boiler

Is your meter being read regularly, have you got last years bills to give you a more accurate idea of your annual consumption. Try reading your meter yourself a bit more often and tweak the controls a bit to see how it affects your consumption. TBH you might improve your consumption a bit by lowering the flow temp a bit, saving hot water by not using as much and altering the timing.

You'd have to have a really well set up system to get boiler efficiencies better than say 90% but it could cost you several £1000's to change it.  Whereas sorting out the controls for a couple of hundred, say with a programmable thermostat, checking the TRV's (or fitting them if you dont have them) and possibly improving the insulation and draughtproofing could well be more cost effective.

It's really not everso helpful to try and compare the energy consumption of your ginormous 160year old house with what's probably a much more modern, possibly better insulated house with cavity walls.

Its a bit like comparing the fuel consumption of a 40year old Landrover with the average fuel consumption of a two year old Ford,  BMW or any other aggregation of modern cars with the same sized engine - you can't

FreeBear

matelodave said: TBH you might improve your consumption a bit by lowering the flow temp a bit, saving hot water by not using as much and altering the timing.

The Potterton Suprima is a conventional non-condensing boiler. Reducing the flow temperature is not going to make much difference (if any) difference in efficiency.

Fitting a programmable thermostat has the potential to save a bit of gas. But that would depend very much on what temperatures it is set to throughout the course of a day. As the Potterton won't have fancy interfaces like OpenTherm or eBUS, there isn't much point in spending a fortune on a Hive or Nest. A two channel Drayton Wiser control would probably work reasonably well.

Turning the HW tank thermostat down to 50-55°C will save a bit of gas - At that temperature, Legionella bacteria will still be killed off, it just takes a little longer.

macman

What is your actual kWh usage over the last year, rather than estimated over the next year? 42K is about double what might be expected for such a property. 
What temp is the room 'stat set to?
The d/g should make a big difference, when was it installed?

InvertedVee

Chickenmum said:

Our home is 160 year old 5 bed Victorian house high ceilings but new double glazing 

We have always had high gas bills in the 17 years we have lived here but the current price increase has made us more aware and on our recent bill we are estimated at 42000 kwh for next year where average 4 to 5 bed appear to be 17000

I lived in a large Victorian house without double-glazing and used 52572kWh of gas in 2017, so it's believable.

FreeBear

macman said: The d/g should make a big difference, when was it installed?

Should, but only if the fitters did a proper job and plugged all the gaps. A recent example of poorly performing windows - https://forums.moneysavingexpert.com/discussion/6406866/winter-grants-loft-cavity-wall-insulation/p4