Gas usage

RichPyke

First off, this is all new to me, ftb just moved in to a house...

I have been testing a few different settings for the ch/hw. First week was on 24/7 set at 21c, boiler (ideal elan) on low, water set for 1 hour each evening (I live alone, that's plenty of hot water) and I used 25 units (790kwh) worth of gas! Week 2 (last week) was heating on high, 21c and set to come on at 5:30-7:30, 3:30-0:00 and it used 26 units (821kwh) of gas! Somehow more for less heat.

I know the boiler isn't as efficient as a newer one would be, it's band G but this seems about 4 times as much gas as I would think it should be.

Any ideas if it's right? or if something seems exceedingly wrong? I have checked the meter and it is imperial, not metric (which I thought could be why it was so high if I was converting the wrong one)

Oh, and it's a 2 bed semi, 3 rads downstairs, 3 up, all are about 1400x600 round top single panel except the bathroom which is a 600x600 single panel. Elec hob & cooker.

It just seems far too high to me, but as I mentioned, this is my first house and I am starting off in the cold spell, but just not sure if it is way too high or just normal for the inefficient boiler.

Any advise is appreciated very much. If it seems stupidly high it will pay to have a new boiler as it'll pay for itself pretty quickly.

HappyMJ

It's wrong because last week was significantly colder than the week before. You need to compare to a neighbour who doesn't change the settings. If you live alone then turn the radiator off or at least right down in the rooms you don't use. Get TRV's installed then reduce the temperature of the bedroom down to about 15 and downstairs to about 20. Keep reducing until you are uncomfortable then put it up again just a little. It's not stupidly high it's a reasonable usage for 6 radiators, hot water and cooking.

KimYeovil

800 kWh, about £30 worth of gas. Hardly expensive for about twice as long as many people (2 hours in the morning and 8 and a half in the evening!!!). Doesn't seem unusual or particularly inefficient. May be more worthwhile investigating your insulation - a pair of curtains and putting your heating off at nine and not on until six will probably be more sensible at first than leaping straight for the ripping-out-your-boiler.

HappyMJ

Ideal Elan is 65% efficient let's say you go all out and buy a 90% efficient one costing £3,000 fully installed. Your bills assuming your gas rate is 3.5 pence would reduce from £28 per week (in the coldest week of the year so far) to about £20. It isn't this cold each week so I'd average that out at about a £2 per week saving assuming again you don't use any heating at all in the summer. You tell me how many weeks that will take to recover £3,000. Too many. When it dies then think about ripping it out.

Pincher

Week 1
______

790kWh at 3p = £23.7 a week for gas.
Assume the boiler is 60% efficient,
so you are actually getting 474kWh of heat into the house.
The hot water uses some of that heat of course, but let's keep it simple.
24/7 is 168 hours, so your house is losing heat at 474/168=2.8kW.

Looks like your insulation is good.

If you had a Band A condensing boiler, you would have used 474/0.9= 526.6kWh in gas, which is £15.80 a week at 3p per kWh.
This is £2.26 a day, very reasonable for 24/7 heating at 21 degrees. Assuming you use £500 in gas with a Band G boiler, you should save £500x30%= £150 a year by changing to a Band A.

At £1,500 for an upgrade, pay back is 10 years, by which time you can expect to replace it again: ten year life expectancy for condensing boiler. The pay back is shortened if gas price shoots up.

Therefore, if you expect to stay long term, change the boiler.
If you intend selling soon, do nothing.

RichPyke

Thanks all.

The reason it's on 24/7 or 5:30-7:30 and 3:30-0:00 is because of the time it takes to get to temperature. On at 3:30 is still quite cold when I get home from work at 5:00-5:15 (15c) and it takes about 30minutes to 1 hour for the temp to drop to a point that it's cold inside, so off at 9 and I would be shivering for at least 2 hours...

If it sounds like the right amount of gas for heating & hot water (no cooking, thats all electric) then I'll stop looking in to upgrading the boiler and use that money (which I don't have...) on insulation.

Once again, thanks all. The boiler change savings are extremely helpful.

JasX

Try setting it to 19 DegC, 18 if you can stand it.

How many rooms in your house? do you need to heat them all? close doors and turn off radiators in the unused rooms?

Do you need it on in the morning at all? if you're just jumping in the shower throwing on some clothes and straight out the door is it necessary? can you knock it off at 23:00 rather than 00:00?