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Thread: Measuring real time gas consumption

  1. #41
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    Quote Originally Posted by DBMandrake View Post
    /snip
    My loop device is connected inside my (metal) comms cabinet to my Fritz!Box router using the tiny ethernet "lead" provided - the gas transmitter is to the right of the comms cabinet (about a meter away) and the electricity reader is about 4 meters away on the other side of the garage and aside from it losing sync with the gas transmitter once (resolved by resetting the gas transmitter and re-pairing it) I've had zero connectivity issues. Hopefully teething trouble and it'll settle down for you - I think it's a really neat bit of kit, not exactly cheap but didn't break the bank either.

    Did you get it on the trial basis? If so, you can send it back if you're not completely happy.

  2. #42
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    Nah I just jumped all in and bought it for the 60. Hope I don't regret it.

    Pretty sure you get a return period even when you buy up front though.

    As long as it maintains a reliable wireless connection with the two sensors I'm sure it will be fine. I'll make some improvements to the mounting of the receiver - it really needs to be secured in a specific location with the right orientation and away from other objects rather than lying on its side in a pile of cables.

  3. #43
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    15 notes cheaper than when I bought it - early adopter pain strikes again

  4. #44
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    Well its been in for a few days and so far so good.

    I was about to mention a problem that seemed to be occurring with spurious detection of gas used but realised what was going on before I put my foot in my mouth!

    When the heating is off for many hours and the house is empty like during a work day, I have sometimes seen a one hour period where it says there was 0.31kW/hr of gas use. If I checked the devices section it would tell me there was one revolution of the meter in the last 2 hours.

    This puzzled me and at first and I started worrying about the possibilities - an inaccuracy of the reading due to light coming through the vent in the door ? Apparently not, because when I've checked the reading manually it is bang on, not even one digit out after several days.

    A BDR91 coming on randomly during the day firing the boiler for a minute then going off ? Certainly a possibility... A slow gas leak ? (We have a gas hob on the stove) Hopefully not!

    Then it finally hit me - the boiler is a pilot light design so there is always a pilot light running.... False alarm...

    And its not even that the pilot light would use a whole cubic foot in an 8 hour stretch, I strongly doubt that it would. However if the previous gas use went off by chance just as the dial on the clock face was nearing the detection point, then the minuscule use of the pilot light over 8 hours may be just enough to push the pointer past the detection point and trigger 1 revolution to be recorded, even though most of that revolution would have been contributed by the previous gas use.

    On a different note - the Loop UI is a bit funky on the explore page, the way the gas reading is added as an afterthought using the compare option - you can use the "myself" choice to compare today's electricity use against yesterdays (but not any other day ?) but the UI design makes it impossible to compare today's and yesterday's gas usage, or indeed compare gas usage with anyone else like you can with electricity ?

    Or have I missed something ? I'm more interested in comparing gas usage against previous days or other people as that is the main cost centre, so it seems a strange omission in the UI...

  5. #45
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    Ten minutes ago (1pm) loop was showing 1.26kW/hr gas usage for the last 15 minute period on the "live" readings on the summary page even though the house is empty and the heating was scheduled off at 7:30am... On the explore page no usage has been registered since 9am.

    When this happened before a week ago I got into a bit of a panic wondering if I'd left the gas hob running (which I am occasionally known to accidentally leave on low under a frying pan!) but it turned out to be a false reading as nothing was on in the house and the explore page did not show any gas usage at all for the time period once it had had time to update.

    Anyone else see the occasional phantom gas usage on the live view on the summary page ?

    Also does anyone know what time period each hour interval is for ? EG, for 9am on the graph does that include usage from 8am to 9am, or is it 8:30am to 9:30am ?

    It shows a small amount of usage at 9am even though the heating was scheduled off by 7:30am so that doesn't seem right...

    I've contacted loop to see what they have to say.

    Other than that it has been running well and I'm starting to build up some useful data. It really does show some startling truths about what does and doesn't consume a lot of gas!
    Last edited by DBMandrake; 6th December 2016 at 02:15 PM.

  6. #46
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    I haven't noticed it do that, but our heating's on all day. I can understand a little spike showing if you cross a boundary on the dial during a period of low usage. Does your boiler have a pilot light or anything like that?

    I did leave the hob on once or twice though.. I was going to write a little Domoticz event to send a warning if the heating wasn't on but gas was being used. Guess I'll be waiting until Spring to write that

    The exported CSV is hourly on the hour so I assume the graph is the same.

  7. #47
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    Quote Originally Posted by jdp80 View Post
    I haven't noticed it do that, but our heating's on all day. I can understand a little spike showing if you cross a boundary on the dial during a period of low usage. Does your boiler have a pilot light or anything like that?
    Yes it does, and it appears that in this instance it was the pilot light. Whoops.

    Normally the pilot light shows as a 0.31kW/hr bump about every 5 hours on the explore graph as the needle crosses the sensor, where I was confused is where the 1.26kW/hr came from.

    I realise now that in both cases you have a single pulse representing 1 cubic foot of gas, one pulse in a one hour period would be 1 cubic foot per hour which is 0.31kW/hr. However the live page is a 15 minute period so 1 cubic foot in 15 minutes would be 4x that or 1.26kW/hr.

    Both readings are misleading because they assume that all of that one cubic foot of gas was consumed entirely within the 15 or 60 minute period respectively, but you can't know that as there is only a single pulse from the needle - in fact it takes about 5 hours for the needle to turn even once from the pilot light.

    You can't accurately measure the rate of gas consumption when it is so low that a single pulse lasts longer than the sampling period. The daily total will still be correct but where on the graph it is shown will depend on where the dial is sitting, and the 15 minute live reading will be more or less meaningless at such a low value. Only when you get at least two pulses in a row in the 15 minute period can you actually measure the current gas consumption rate by timing how long it was between pulses.

    I could have sworn that last time this happened there was no bump on the explore graph, but maybe I was wrong...
    Last edited by DBMandrake; 6th December 2016 at 02:38 PM.

  8. #48
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    I've had loop for 3 months now so wanted to do a little mini-review of it and let people know if it ended up helping me or not. The short answer is yes.

    Accuracy of the gas reading is excellent - after two weeks or so the last red digit was only out by one or two numbers, which is very good. Accuracy of the electricity reading will only be average because as discussed it doesn't take into account power factor or voltage. However I believe that this approximate reading is probably within 10-20% (especially when most big loads like electric shower and ovens are resistive) and therefore "good enough" when it comes to watching your usage and trying to keep it down. It will certainly let you compare two different days or observe trends.

    Being able to monitor electricity and gas use on a daily, weekly and monthly basis both in kWh and cost, rather than getting 3 monthly bill shock really has woken me up to just what does cost and what doesn't. I have our Evohome schedule set fairly economically - rooms that aren't needed or aren't used much at a certain time of day are ruthlessly set to lower temperatures or set off, and if we do need those rooms unexpectedly we manually turn them up. On occasions where we have got a bit carried away and turned all these rooms up at once the increase in gas usage is immediate and stark - one recent Saturday we were doing a tidy up of the entire house and as such had the temperature turned up to comfortable levels in all rooms for most of the daytime, the look of horror on my face the following day when I realised our gas use was over 50% higher than normal that day was priceless.

    If I didn't have that immediate feedback to say "no, no no, don't keep doing that" I may well have decided that having all rooms in the house toasty warm more often was a good thing, until the bill arrived at least... It also allows you to fine tune your temperature schedules and get immediate feedback on what difference it makes.

    For example Kitchen, Hallway and Living room used to come on to 20 degrees in the morning before work, and in sub zero temperatures the hallway radiator struggles to reach 20 so the boiler (or at least the boiler relay) tends to run continuously to try to reach the target. However I found that just dropping those three rooms to 19 degrees was enough to cut gas usage in the morning down quite a lot - because the room can easily reach 19 and allow the boiler relay to be TPI modulated right down. In fact in recent mornings (8-10 degrees unusually mild) I've actually seen the boiler (and pump overrun) go off completely in the mornings once those rooms were up to temperature.

    Other features about loop that are nice are the weekly reports that get emailed to you, and the energy budget reports, where you can set your target monthly budget, and it will email you at 25/50/75 and 100% of that budget to let you know how you are doing and whether you are making your target or not.

    Being able to see usage in both kWh and for a day, week, month or 3 monthly is great, however one small niggle is that you can't specify an arbitrary date range, for example to do a direct comparison with your energy companies bill, as they tend to be billed over odd periods of time. (You could export the data as CSV and do an Excel sum though if you really wanted)

    Also, you can compare your electricity use to previous usage of your own as a graph overlay, but you can't tell it when to compare to (only the previous day/week/month etc) nor can you do a gas comparison. This means if you try to compare Monday's electricity use with previous use your only choice is to compare it with Sunday - but given that you're comparing a week day to a weekend that's hardly fair. There isn't a way that I could compare Monday to an arbitrarily chosen day.

    All in all well worth the 60 I spent on the hardware, and it is something I continue to use and monitor every day to keep an eye on things.

    The other side of loop is that once they gather "enough" data, they will then use uswitch to start offering you "better deals", which has both good and bad sides to it. I remember saying I would be ignoring their recommendations and doing my own research, but the good side of it is that when the feature unlocked after a month and started making recommendations to switch it did (quite painfully) draw my attention to the fact that we were grossly over-paying for gas on an old fixed rate plan, and have been for at least a year now...

    If it hadn't put that right there in my face and nagged me about it I'm not sure that I would have bothered to go out and do the research on my own on dozens of different providers to see what was out there and how our current rates compared, so it got me off my backside once I realised how much we could be be saving.

    Their top suggestion was bulb energy (who I've never heard of before, not that I go looking in my spare time though! ) and I did a little research on the top four recommendations they made, as well as doing a little dig around on my own, but I kept coming back to bulb, especially after reading bulb's blog, customer support forum etc, and liking what I saw. I'm someone that likes to support the little guy rather than the big corporates, so to be honest they had me already at that point given how much better their tariff was, but the fact that their focus is on renewable's (100% electricity and 10% gas at the moment) was a nice bonus, as I'm all for encouraging renewable energy as we gradually transition to the likes of electric cars etc... I reached out to them on their customer forum with some questions and got replies within an hour even though it was late at night, and I've since had some good email dialogue with them as well.

    To give you some idea of the difference between tariffs, our current fixed rate tariff is "Fixed Price Mar 17" with Scottish Hydro, which is a whopping 4.62p/kWh for gas. After March 17 if we did nothing we would go onto their Standard variable tariff which ironically is actually cheaper than their fixed tariff... but only by a modest amount. Bulb is a variable tariff with a current gas price of 2.47p/kWh - yes that's right, only 53% of what we are currently paying...

    Now, their standing charges are quite a bit higher but still don't make much impact on the overall cost, and their electricity rate is a little bit higher too, but that only amounts to about 2 per month as electricity is only a minor cost in our house. On the gas side we're looking at approximately 50 less a month averaged over a year.

    Of course with a variable rate you run the risk of increases, but if you're starting off so much lower in the first place they would have to go up a lot to even get back to where we started, and they also pay your previous suppliers exit fee but have no exit fee of their own so if things did go bad I could just jump ship again, so I decided let's go for it! One drawback with bulb is if you join during the winter your initial payments are set at 20% higher than your normal yearly averaged monthly rate, but only for that first winter. They say this is to stop you getting into debt during that high usage period when you haven't already built up a credit over the previous summer, and it makes good sense to me, however it could be a sticking point if part of your reason for switching is needing an immediate savings rather than long term savings. (However in my case even the 20% higher initial payments are still a lot cheaper than what I was paying before)

    I don't want this to sound like an advert for bulb by the way - I've never heard of them before this and just wanted to share what I ended up doing after getting a loop monitor. I don't even finish switching to them until the 26th, so it remains to be seen how good they are in the long run, but I am hopeful.

    This now brings me to a major flaw in loop - their method of estimating your usage for offering deals via uswitch is flawed. The feature unlocks after 30 days however it attempts to generate a year averaged estimate of your usage based on that first month of using loop. For me that first month was half of October and half of November - both unseasonably warm. So their estimate of my yearly energy use was way out in the "not enough" direction. Ironically this means the savings from switching will actually be more than initially suggested by them as they underestimated my usage.

    However as each month since then went by I kept expecting to see their recommendations change and be updated to reflect a more accurate estimate from more time monitoring my usage - but it never did. Even though I've now been using loop for 3 months and have 3 months of usage recorded their switch recommendations are still using the same inaccurate data from mid October to mid November, and I can't find anything in the user interface to tell it to go re-calculate based on all the additional usage data it has gathered since.

    This became a major issue when I tried to switch to bulb using the loop website - I thought I might as well give them credit for finding bulb for me, (so they can get a commission) however it automatically tried to sign me up based on a monthly rate calculated from that inaccurate extrapolated usage estimate, which would have seen my initial monthly bill to bulb being about 50 below what I knew it ought to be, and there was no way for me to manually change or override it through the loop interface.

    So in the end I looked up my previous yearly summary from Scottish Hydro to use those figures and manually filled that in directly with uswitch, which gave a monthly figure that was very close to what I was expecting. So unfortunately loop missed out on their commission there! So if you're reading loop, you need to improve your website both to update the projected yearly usage as you gather more data, and also allow the user to override the sign up figure if the estimated usage figure is too low!
    Last edited by DBMandrake; 19th January 2017 at 04:16 PM.

  9. #49
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    An excellent and helpful review - thank you. In case anybody is thinking about switching to Bulb, it is a supplier (and it may be the only one) that makes an extra charge for an IGT gas supply. If I recall, it is about 100 a year extra.

  10. #50
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    What's an IGT gas supply ?

    That acronym went right over my head I'm afraid...

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