Gas usage

[martyc]

Hi,
just checked my average gas usage and its working out at 9KWhr per day over the last week which has been cold enough i guess.
Edit....just under 100KWHR per day...which is roughly £3 here.
House is 1200 square feet 2 storey semi d..attic well insulated(270mm), PVC windows,cavity block construction but no wall insulation.
A few draughts but not too bad.
8 rads, 4 are 3 to 4 foot wide doubles rest are singles of about same size.
Heating is on for an hour and a half in the morn and 5 hours in the eves.
Boiler is ~17kw if i remember correctly and currently only heating the CHW.
does that usage sound reasonable?
Cheers,
Marty.

 

[JohnD]

very reasonable

I hope you have a room stat and some TRVs

 

[martyc]

John...that should have read "100kwhr per day"...yeah i have trv's and a stat.
Still reasonable?
Marty.

 

[JohnD]

not so reasonable.

I have a fair-sized modern house, cavity insul etc, 6 double rads running, heated to 20C 12 hours a day, I used 50kWh per day average end Sept to end Nov 2007

South coast so warmer than you

My Dec 2006 to Mar 2007 was 86 kWh/day average

Do you have a lot of hot baths?

 

[martyc]

No..in fact i recently closed the valve to the hot water cylinder!

Dont shoot me down now here..but could the fact that the casing/housing is off the boiler be increasing usage?
Boiler is in garage and its not draughty out there..but it aint heated either out there!!(i took the casing off to replace the PCB a while back and err didnt put it back on yet!!)

I have read all the other posts and there is apparently a way of detecting if the boiler is using what it should be...counting how many of the red dials increment in a minute?
Marty.

 

[JohnD]

you can calculate from cu.m to kWh but you'll have to look at your gas bill to see the calculation.

I am just a householder.

My own boiler runs for a bit, then stops, and fires up again on demand at intervals, so it doesn't run at 22kW for long, on average, maybe a fifth or a tenth of that, i don't know.

Your naked boiler will be acting as a big radiator to keep the garage warm with wasted heat. I hope the pipes are lagged too, especially in unheated areas. the BS pipe lagging is as thick as your arm in stiff polythene foam.

The cylinder will also be acting as a big radiator if not well insulated.

 

[martyc]

Thanks john,
Ill get the cover back on it..laziness im afraid!
I lagged the pipes alright but only with regular stuff.

Anyway i just took some readings to see if they add up.
I ran it for one minute and the red dials moved from 688 to 720, thats .032 of a unit (im in ireland so may be different to u guys)
Now according to my bill if i multiply this by 10.9321 i get kwh.
so 32* 10.9321 = .349Kwhr in one minute...this part sound OK?
multiplied by 60 = 21Kw
Boiler says it is min 14.8KW and max 18.3

Cheers,
Marty

 

[JohnD]

you've lost me

but perhaps a Gasman will be along in a minute

 

[martyc]

Actually just did same test for 3 minutes with a proper stopwatch.(last test was using a less than reliable method!!)

It used on average .027333 units per minute...which converts to 17.9KWhr.
So i can only assume thats fine based on the parameters i gave above.

I have my boiler set quite high in the assumption that my room stat will do it business (and it does.)
But this leads to really boiling rads during heatup...is this Ok or would it be better to turn the heat of the water leaving the boiler down?
Cheers,
Marty.

 

[JohnD]

if the rads get very hot, there will be excess heat after your room stat has been satisfied.

 

[martyc]

Ill turn down the output on the boiler and i have all my figures written down and ill see how it performs over the next 24 hours!
Based on my calcs...if i am using 100KW per day and my boiler is running at 17.8KW then my boiler is firing for 5.6hours a day..i only demand heat for 6.5 hours so thats 86% on time which sounds high.
I have one of those clever honeywell room stats and it seems to me to have the boiler off about half the time so something doesnt sound right.
Ill see what the meter reads this time tomorrow.
Thanks,
Marty.

 

[doitall]

Actually just did same test for 3 minutes with a proper stopwatch.(last test was using a less than reliable method!!)

It used on average .027333 units per minute...which converts to 17.9KWhr.
So i can only assume thats fine based on the parameters i gave above.

I have my boiler set quite high in the assumption that my room stat will do it business (and it does.)
But this leads to really boiling rads during heatup...is this Ok or would it be better to turn the heat of the water leaving the boiler down?
Cheers,
Marty.

Thats Gross input, so get the boiler stat down to less than half way

 

[ChrisR]

Gas usage - see FAQ for calculations, around number 38 ish iirc.

 

[Agile]

...if i am using 100KW per day

That is a RATE of using power! My phone battery can do that in 20 mS if one ignores the internal resistance.

You should be be looking at kW HOURS !!! Thjats a measure of the ENERGY consumed.

This is all basic "O" physics, not so sure about the dumbed down GCSEs though!

Tony

 

[doitall]

...if i am using 100KW per day

That is a RATE of using power! My phone battery can do that in 20 mS if one ignores the internal resistance.

You should be be looking at kW HOURS !!! Thjats a measure of the ENERGY consumed.

This is all basic "O" physics, not so sure about the dumbed down GCSEs though!

Tony

He has Tony 17.9, although I came up with 17.4 Kw/hr