Views please on gas usage

Cirrus1

spudwood said:

Since then, I've tested the usage many times by reading the red numbers (ten of these equate to 1 hundreds of cubic feet) and the readings for an hour's usage are consistently 0.6 hundreds of cubic feet, which converted to kWh (0.6 x 2.83 x 1.02264 x 38 / 3.6) is 18.3 kWh.

My question to the forum is: does 18.3 kWh seem high for an hour's usage and as such, could it mean there's a problem with my boiler or that my old gas meter could be inaccurate. The boiler was serviced recently; no issues identified.

Look forward to your replies
Thanks

I think it’s quite difficult to answer your question because there are so many variables involved like flow temperature, outside air temperature, size of boiler (which you have given), whether boiler can be modulated by a smart thermostat etc.
You also say that you have checked your meter several times and you consistently get 18.3kWH. On the basis of your post, I decided to check my data. I had a lot of work done on my system during summer, so this is the first opportunity to see the effects.

I have a smart meter and use several apps, so I can easily see my data in 30 minute intervals. I find that the most important factor in my boiler’s gas consumption is the outside air temperature and whether it has just started. I also see variable consumption of gas during the day.
E.g. Yesterday was a mild day (high of 14 degrees). The boiler used ~30kWh in the first hour. I can also see ~8kWh at other 1 hour intervals, to maintain a room temperature of 20 degrees.
During the really cold spell (one of the -7 degree days), I can see a 30min interval that uses 18.5kWh! On a good day, I can see that the room temperature of 20 degrees is maintained by 4 kWh of gas.
So to return to your question - I’m puzzled by your boiler having a constant gas consumption, but your value is in the ballpark of my range of 4-30kWh. This is with a constant flow temperature and the room temperature is kept in a 2.5 degree window.

spudwood

PeterGr said:

If your December usage is 1832.9 kWh, and you think the hourly usage is 18.3 kWh, then that would be about 3 hours per day.  So there are over 20 hours a day when your usage is 0.   Daily readings over a period is more likely to give you a better idea of your boilers performance.   If you have read the meter for the first hour that the boiler has come on for instance it is not surprising that the consumption is similar.

This is what I've been doing ie measuring it when it comes on from cold so thank you for pointing this out

spudwood

Cirrus1 said:

spudwood said:

Since then, I've tested the usage many times by reading the red numbers (ten of these equate to 1 hundreds of cubic feet) and the readings for an hour's usage are consistently 0.6 hundreds of cubic feet, which converted to kWh (0.6 x 2.83 x 1.02264 x 38 / 3.6) is 18.3 kWh.

My question to the forum is: does 18.3 kWh seem high for an hour's usage and as such, could it mean there's a problem with my boiler or that my old gas meter could be inaccurate. The boiler was serviced recently; no issues identified.

Look forward to your replies
Thanks

I think it’s quite difficult to answer your question because there are so many variables involved like flow temperature, outside air temperature, size of boiler (which you have given), whether boiler can be modulated by a smart thermostat etc.
You also say that you have checked your meter several times and you consistently get 18.3kWH. On the basis of your post, I decided to check my data. I had a lot of work done on my system during summer, so this is the first opportunity to see the effects.

I have a smart meter and use several apps, so I can easily see my data in 30 minute intervals. I find that the most important factor in my boiler’s gas consumption is the outside air temperature and whether it has just started. I also see variable consumption of gas during the day.
E.g. Yesterday was a mild day (high of 14 degrees). The boiler used ~30kWh in the first hour. I can also see ~8kWh at other 1 hour intervals, to maintain a room temperature of 20 degrees.
During the really cold spell (one of the -7 degree days), I can see a 30min interval that uses 18.5kWh! On a good day, I can see that the room temperature of 20 degrees is maintained by 4 kWh of gas.
So to return to your question - I’m puzzled by your boiler having a constant gas consumption, but your value is in the ballpark of my range of 4-30kWh. This is with a constant flow temperature and the room temperature is kept in a 2.5 degree window.

Thanks for going to the trouble of checking your usage. Is your boiler set at 20 degrees all day and therefore comes on and off to keep to that temp? I have been checking the gas usage from cold every time and from the helpful replies I've had so far, that explains why I am getting consistent meter readings. I find that I am warmest when the boiler is actually kicking out heat so I am okay with a lower temperature in the house (as indicated by the thermostat) but I tend to switch it on and off manually several times a day, to get that blast of heat. So more often than not, its starting from cold. 

Cirrus1

OP - I have different thermostat temperatures for different times of the day. Night is 17.5 degrees, first thing is 20 degrees. When that is achieved, it’s usually about 9am and the room benefits from solar gain for a while. Definitely 20/+ in the evening.
I’m not completely profligate with the heating. I have smart trvs and the bedrooms/other rooms have different temperatures for different times of the day. I can concentrate the heating to just the living area of the house. I too am warmest when the boiler is on!

Alnat1

We live in a fairly well insulated 2003 house but I've still tried to make a few adjustments that seem to have helped this winter.

I've added thermal linings to the downstairs curtains and make sure they are closed at dusk. We have an open fronted (fake coal effect type) gas fire that is never used so I stuffed a cushion up the chimney to help stop heat escaping.

Best thing is my heated throw that I use after dinner. It costs less than 10p each evening to run and has allowed us to reduce the thermostat to 17.5C (I'm nesh!). The heating is on all day if we're in, off 10pm-6.30am (left on at 14C overnight during that Dec cold snap) boiler flow around 50C (up higher in cold snap).

TRVs in unused rooms at 1.25-1.5, our bedroom and bathroom 2.25, kitchen on 3, living room (where stat is) on full.

Every home is different and it takes a lot of little adjustments to get things balanced, turning a TRV a few mm does make a difference. You don't want to be miserable and feel like you're sitting in a fridge but I think we're all realising that putting on a jumper on is better than turning up the stat.

ariarnia

spudwood said:

I used 1832.9 kWh in December 

i know others have replied but the way i would look at it is you used about 60kwh a day over the month.

only you know how long your heating was on for (on a timer or an average of you turning it on and of) but one thing i dont think anyone else has asked is does that use also include heating water (showers washing up etc)

i also wanted to point out that on cold days (that cold snap we have) the boiler would use more gas to heat the house to the same temp (the house will lose heat faster when its colder outside). so measuring for just an hour doesn't really give you the true picture but also comparing days when the temp outside is very differnt can also be a thing. 

DeeQS

spudwood said:

DeeQS said:

It's not that high for the first hour of running. Your boiler is an upto 28kWh boiler. The first hour always uses more energy as it heats all the water from cold. Once the water is hot the boiler will cycle down to use less energy to just maintain the water at the set temperature.

Have you tried running it for 2 hours and taking the same measurements to check this?

Say if I set it going at 17 degrees and wanted it to reach 19, would it still use less over time as the water warms up or would it still be going at full pelt to get to 19? 

It should still use less energy over time. The boiler will run at a variable power output to heat the water. The water heat is transferred to the room as the system runs. The boiler doesn’t know what the room temp is, or what it’s set too. That’s the thermostat and that is a simple call for heat (yes/no).

We have underfloor heating, but the principle is the same. When I turn the system on the boiler runs at 18kwh output for about 45minutes to do the initial water heating. Then depending on how many rooms are on, it can reduce back to less than 4kwh for the remainder of the heat time until the room warms and the thermostat stops calling for heat.

Astria

Consumption 171.0 Units (m3)
Energy Used 1904.3 kWh @ 14.058p/kWh £267.71
Energy Price Guarantee 1904.3 kWh @ 4.22p/kWh -£80.29

Standing Charge 46 days @ 27.128p/day £12.48

VAT @ 5% £10.00

Total Gas Charges £209.90

That's 15th Nov to 31st December, so seems pretty much like other peoples, but it's on pretty much 24/7 as I WFH.

jrawle

spudwood said:

Hi, I have been monitoring my gas usage closely since receiving my last gas bill for one month, December 22, of ~ £200. I am with E-on. I pay for what I use each month and send meter readings to E-on each month. I have a 12 year old Worcester Bosch Greenstar 28i Junior Boiler. I have an old imperial gas meter, a Schlumberger which has four white digits and then a decimal digit in red. I don't have a smart meter.

I used 1832.9 kWh in December which is the 60 hundreds of cubic feet I used (as measured by my imperial meter) x 2.83 x 1.02264 x 38 / 3.6. 

[...]

I don't think your usage seems excessive for December, given the period of freezing weather we had. I consider myself to be fairly frugal with the heating, yet my gas usage for December was ~ 1600 kWh.

The boiler will run flat out when heating from cold, and as you have a 28 kW boiler, the usage seems about right. I think you are doing the right thing putting it on manually when you feel cold. I agree that it is pleasant to feel the heat from the radiators. Also, if you leave it off when you don't feel cold (perhaps you are walking about, doing housework, etc.) you are going to make a saving. (I always think that if I had my heating on continuously so that it was continually providing small amounts of top-up heating as some people advocate, I'd probably have to have the thermostat much higher in order to feel comfortable, without feeling the heat from a hot radiator and the times I was particularly cold.)

Unfortunately, the 1800 kWh figure is just what it takes to heat your house when we've had cold weather, and the cost is high due to current gas prices. I don't think there is anything wrong or abnormal about your usage.

vic_sf49

Hiya @spudwood.

I'm the one with the same boiler as you, chatting on your other thread.

Ignoring December because of that cold snap, as I changed my overnight thermostat settings so the boiler kicked in more, and/or became the outdoor temps were massively different from this week.

In the first hour of morning heating:

- Nov 22, flow temp = 5 = 12.5kWh.

- This week*, flow temp = 3.5 = 9.5kWh.

* Only changed the flow temp this week, so not much data yet.

Detached 3 bed bungalow. East Midlands. Good loft insulation. Majority (90%) of walls cavity filled.