Views please on gas usage

spudwood

Thanks for coming over to this thread Vic

I'm in a two bed semi. Have got loft insulation but not cavity.  Would the amount of insulation impact on how much gas the boiler used in the first hour of heating? Mine is using significantly more than yours was in Nov at the same flow temp. This morning after I'd changed the setting to 4, I measured it over a 40 minute period and it still used 12kwh. 

macman

spudwood said:

Thanks for coming over to this thread Vic

I'm in a two bed semi. Have got loft insulation but not cavity.  Would the amount of insulation impact on how much gas the boiler used in the first hour of heating? Mine is using significantly more than yours was in Nov at the same flow temp. This morning after I'd changed the setting to 4, I measured it over a 40 minute period and it still used 12kwh. 

Yes, because the faster the rate of heat loss, the harder the boiler has to run to replace the 'missing' heat. Heat loss is directly related to the differential temps, indoor and outdoor. The greater the difference, the faster the loss rate.

vic_sf49

macman said:

spudwood said:

Thanks for coming over to this thread Vic

I'm in a two bed semi. Have got loft insulation but not cavity.  Would the amount of insulation impact on how much gas the boiler used in the first hour of heating? Mine is using significantly more than yours was in Nov at the same flow temp. This morning after I'd changed the setting to 4, I measured it over a 40 minute period and it still used 12kwh. 

Yes, because the faster the rate of heat loss, the harder the boiler has to run to replace the 'missing' heat. Heat loss is directly related to the differential temps, indoor and outdoor. The greater the difference, the faster the loss rate.

I'm so glad someone beat me to the answer, as that was explained far better than I'd have managed.

vic_sf49

I should add, my bungalow isn't necessarily up to temperature in that first hour, it was just a logical point from which to look at a small snapshot of my usage.

For info, my internal temps have only dropped to 17 degrees overnight this week.

Seeing how well my system performs on a lower flow temp, will not be obvious for a good while yet, years even.

While my loft and cavity insulation are good, having the whole property sitting on the 1970s, uninsulated slab of concrete, doesn't help matters. 

jrawle

vic_sf49 said:

I should add, my bungalow isn't necessarily up to temperature in that first hour, it was just a logical point from which to look at a small snapshot of my usage.

What does it really tell you to look at one hour's usage when the boiler starts up? Surely all that matters is the total energy usage averaged over the day. If the boiler uses a huge amount of gas for the first hour in the morning, but little after that, that could still be better than it consuming less for the first hour but continuing to do so for hours and hours throughout the day.

markin

It could also be more water volume, older rads with thicker steel, And also different part of the country so cooler and more windy.

vic_sf49

jrawle said:

vic_sf49 said:

I should add, my bungalow isn't necessarily up to temperature in that first hour, it was just a logical point from which to look at a small snapshot of my usage.

What does it really tell you to look at one hour's usage when the boiler starts up? Surely all that matters is the total energy usage averaged over the day. If the boiler uses a huge amount of gas for the first hour in the morning, but little after that, that could still be better than it consuming less for the first hour but continuing to do so for hours and hours throughout the day.

 As a direct comparison to the OP's figures, and in answer to their question, it may be useful as we have the same boiler, but very different figures. It might highlight how more insulation can help.

But as I said in a different post "Seeing how well my system performs on a lower flow temp, will not be obvious for a good while yet, years even"...there's a long way to go yet, and even comparing years, can show vastly different usage, or it has in my case.

I'm all of 4 days into this "lower flow temp" experiment, so checking that hour is probably the best indicator I have right now, as to how the system might perform longer term. It's been using a couple of kWh less so far, but I haven't recorded external weather conditions, so who knows.

I shall continue pootling along in experiment-land, and if I cut down usage, then that's good, but I won't be skimping on my usage to the detriment of my comfort & warmth.

Edited as formatting goes a bit strange when I post from my tablet.

spudwood

@vic_sf49 'pootling along in experimental land' made me smile. I have to say, my experimenting at the moment is driving me a bit mad. I am convinced my meter is fault haha.

I appreciate that there are many factors that impact on overall gas usage such as insulation, outside temp, etc etc but just measuring the output of 2 of the same boilers over an hour period surely should result in similar usage levels?

At this point in time, if hair shirts were still in fashion, I'd probably wearing one as I am restricting my usage to the point of discomfort at times. I may try your timings and setting for a 24 hour period at some point and see what my usage is over that period. 

Today I turned my boiler down from 5 to 2 just to see. It was off overnight and the temp was 13 degrees this morning. I turned the boiler on for 2 hours by which time it had used 18kwh and got to 16 degrees. I turned it off at that point as was going out for a few hours. Any views on this?  It still appears to be burning through the gas at almost as high a rate from cold as it did on number 5. I think 2 was too low today as it was pretty nippy today here in Yorkshire but on a milder day think it would be ok I think. (I did have the boiler on later as well but by that point cba to check what was going on with it!)

vic_sf49

One main thing from your last post, is the temp your bungalow dropped to overnight was 13 degrees, whereas mine only dropped to 16.1. (Heating went off last night at 1915 @ 20. 2 degrees.)

So you may be somewhere far colder, more remote, or my cavity wall insulation is making a big difference, therefore your boiler will be heating for longer.

Another "oh, I wonder" moment from me, is that on paper, my property is bigger, so potentially more radiators, and maybe a lower return temp at the boiler through pure dumb luck, so my boiler is working slightly more efficiently.

I'll now sit back and wait for some "oh yesses", "definitely no chance" or "what on earth are you prattling on about" comments from the experts.

vic_sf49

And your December usage was 1832.9kWh I think you said? Mine was 1858kWh* (high flow temp still set in Dec). Spookily similar.

Looks like my smets2 smart meter is in cahoots with your older one.

*my calculation from m3, whereas BrightApp says I used 1854kWh.