Average Daily Gas Consumption

Cardew

flashnazia wrote: »

How much gas should a 10 min shower use (estimate?)

The best way to estimate would be to compare consumption with a high powered electric shower of 10kW.

This will use 2kWh for a 12 minute shower.

Assuming that a combi fed shower would not produce more hot water than an electric shower, that would mean that a 12 minute shower would use just under 0.2 of a gas unit.

flashnazia

Well, measured the gas use of a shower and it was less that one unit (should have read the read digits but didn't - will do next time).

The boiler is 24KW.

It must be the heating then but I haven't put it on for ages. Unless it was in April (and I can't remember). Was it cold in April? I remember it being hot?

It can't be the cooker cos thats newish.

Have a gas fire in living room that is quite old but surely that won't be the culprit.

So if my boiler is 24KW am I right in thinking it costs me nearly one pound per hour!!!:eek:

(Based on approx 4p per kwh x 24).

mech_2

flashnazia wrote: »

It must be the heating then but I haven't put it on for ages. Unless it was in April (and I can't remember). Was it cold in April? I remember it being hot?

Here, April started off reasonably (10 degrees C), but started falling on the 5th to 2 degrees for the 6th and 7th. Then it was about 6 degrees C until the 20th. After that the weather suddenly got much better.

Have a gas fire in living room that is quite old but surely that won't be the culprit.

Aha! It could be that if you have been using it. Old ones can be atrociously inefficient. I can heat my whole house for what it costs to heat the living room with my old gas fire. I don't use it at all any more. My sister stopped using hers too, as she found it was cheaper to heat the room with an electric fan heater.

So if my boiler is 24KW am I right in thinking it costs me nearly one pound per hour!!!:eek:

(Based on approx 4p per kwh x 24).

It might do for hot water if it's not a boiler that can adjust the intensity of its flame. My experience of my sister's non-condensing Worcester Bosch combi was that if someone was having a shower, the boiler stayed on constantly. This means while you're showering you have to turn up the cold water after a few minutes as it just keeps getting hotter.

However, my condensing combi varies its output to match the load when it's burning. I can hear the burner fan speed up and slow down while the water is running.

For central heating the maximum rating is fairly immaterial. The boiler will switch on and off to maintain the right temperature in the house, whatever kind of boiler it is, so it won't be constantly on.

Cardew

flashnazia wrote: »

So if my boiler is 24KW am I right in thinking it costs me nearly one pound per hour!!!:eek:

(Based on approx 4p per kwh x 24).

No not at all.

24 kW is the maximum output of a boiler and it might just possibly use that amount for a few minutes when it is providing hot water or initially running central heating in winter when the input water is very cold.

Mazio_2

My central heating was still on for most of April I cant tell you the outside temps though. This has had an impact on my usage as well even though I had full cavity wall insulation and increased the thichness in the loft late last year my usage has increased becauce of the prolonged winter.

moonrakerz

Actual Figs:

3 bed detached (1970s), gas warm air c/h, 6 kWh gas fire in lounge, gas water heater on 24hrs. Everything else electric.

19 Jan 2008 to 29 Jun - 63.7kWh per day
19 Jan 2008 to 03 May - 88.7kWh per day (03 May c/h turned off, fire used a couple of times since !)
03 May 2008 to 29 Jun - 17kWh per day

Thought costs were quite reasonable - especially as I moved (in Dec) from an oil fired house !!!
Am now giving very serious consideration to Cavity Insulation & extra loft lagging as well.

mech_2

I like graphs.

1930s 3-bed semi, gas condensing combi with radiators. Hobs are gas, oven is electric. Gas fire in lounge is never used. The heating contribution from my electrical usage is around 4 - 6 kWh per day.

The boiler was completely off when I was away (indicated). The heating was off between 4 May - 16 May. It has also been switched off since the end of the graph. Average usage since then has been about 7kWh/day. The heating was on a timer from 28 March - 15 April as an experiment (8 hours out of 24, including weekends. No clear benefit shows on this graph but it's probably a saving of 5% - 10%). For the other periods the heating was on 24/7.

It's interesting to see how much energy is required to bring the house back up to temperature from cold. It seems to take 24-36 hours for gas usage to stabilise even though the indoors air gets to temperature relatively quickly.



I'm not sad enough to take readings all the time. I built a box to do that for me. Readings were taken every 30 mins. Outside temperature information is from a local weather station, also every 30 mins. Running 24-hour averages were then generated to smooth out the data. Solar gain calculations are an approximation, but fit older, manually obtained data too.

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flashnazia

mech wrote: »

Aha! It could be that if you have been using it. Old ones can be atrociously inefficient. I can heat my whole house for what it costs to heat the living room with my old gas fire. I don't use it at all any more. My sister stopped using hers too, as she found it was cheaper to heat the room with an electric fan heater.

Really? I can't believe it? How? Does the heat escape up the chimney or what?

I only keep it on low (middle bar alight) on cold evenings thinking it's cheaper than heating the whole house.

What kind of KW usage would that be then? Surely that can't be using all that gas?

mech_2

flashnazia wrote: »

Really? I can't believe it? How? Does the heat escape up the chimney or what?

Yes.

I only keep it on low (middle bar alight) on cold evenings thinking it's cheaper than heating the whole house.

What kind of KW usage would that be then? Surely that can't be using all that gas?

These figures are purely guesswork, but if the fire is 35% efficient and puts out 1.5kW of heat when on low, then it's using 4.28kW of gas. If you have it on for 5 hours in an evening, then that would use 21.43kWh of gas, or about 1.9 units on a metric meter.

It's difficult to give a reliable answer as efficiencies vary wildly. You can go out tomorrow and buy a new gas fire that is 35% efficient, or you can find ones now that are over 80% efficient. Old gas fires are likely to be at the bottom of that range. My gas fire looks as if it was installed in the 1960s. My sister's looks no more than 20 years old, but seems no more efficient.

One clue is that if it has glass in front of the flame it is potentially more efficient than one without.

Apologies for the delay in responding. I have been away and without internet access.

flashnazia

No need to apologise for late reply. I'm grateful for the opinion.

I've stopped putting on gas fire now. I won't even let the other half (who is always cold) go near it; let alone turn it on.

I think you are right about it's inefficiency and sometimes I can even smell a slight whiff of gas (almost as if it wasn't burning it properly).

The solution now is to get a new one which won't be easy as it's a weird recessed fireplace.

I'm thinking of putting another radiator in here too as the central heating doesn't warm the room up (hence me putting gas fire on to compensate).

I haven't checked my consumption yet to see if stopping the gas fire use has helped. Only because my meter is in the deepest darkest spot of the cellar (last time I bashed my head down there). I won't even let the meter reader in cos it's such a tip and s/he might sue me!