Crazy Gas Usage

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Crazy Gas Usage

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dur77dur77 Forumite
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Hi All - wondering if any experts can shed some light on this.
We have had a new boiler system put in - Vaillant Ecotec pure630 with an unvented cylinder - pressurised from mains supply. It is a 5 bedroom house, so I expected the bills to be high but not this high!
Our dual fuel bill was £600 for 2 months! When looking at the meter reads, the clear culprit is the gas usage:
- Electricity: 1090 kwH used over 2 months (£210), i.e. 545kwh per month
- Gas: 840 units used over 2 months - works out as 9300kWh (£380), around 4650KwH per month!!!!!
The boiler is on constantly for central heating, but is controlled by a thermostat in the living room - so only switches on when the living room temperature drops below 21 degrees and then switches off when it gets to that temp. When it is on, all the radiators in the house are on with the individual radiator valves onto maximum output - presumably that doesn't matter, because the boiler gas heating is only being driven by the living room thermostat telling it to switch on and off during the day and night?

In terms of hot water, I have set this on for 2 timed sessions a day - 30mins in the early morning and 30 mins in the evening.

Am I missing something obvious here, what is driving such high gas consumption, or is this about right for a thermostat controlled system? Should I be switching the boiler off completely and just turning it on when we need it? The room with the thermostat in is usually very warm, so it is not like the boiler is switched on constantly trying to get the room to 21 degrees - there ar 2 radiators in there, so it gets to the specified temp pretty quick. Sometimes we have to make it go higher than 21 so that the heating can come on in other rooms of the house where it is still colder?
Any thoughts, much appreciated....


  • edited 26 March at 2:46AM
    TalldaveTalldave Forumite
    988 posts
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    edited 26 March at 2:46AM
    Your biggest problem is the price you're paying, not the consumption.  We're also 5 beds and highest winter gas use is around 6000kWh per month, so more than you but this place has a large extension. But we pay 2.37p per kWh, so 9300kWh would be £220 (plus £10.50 for 2 month's standing charge).

    Your electricity consumption is a bit high, but we pay 11.45p per kWh so 1090kWh over two months would be £135. Look at where this consumption is going - halogen lighting or old fridge/freezer??

    As for the heating, shut off radiators in rooms you don't use, or at least set their TRVs lower - but then shut the doors. It sounds like the system is badly designed if the room where the thermostat is located is getting too hot whilst elsewhere is too cold. With a single thermostat you need it in the coolest/hardest to heat part of the house and then rely on the TRVs shutting off radiators everywhere else as rooms reach the desired temperature.

    I'm not quite sure what to suggest, as the system should have been balanced (flow through each radiator adjusted) to prevent the imbalance you're experiencing. A quick fix would be to shut off one of the radiators in the living room (or significantly reduce the  flow through both radiators) - that'll slow down the speed at which that room heats up and level off the temperature across the house. Hopefully you have a programmable thermostat with optimum start that learns when to switch the boiler on to achieve the temperature you've set? (We have the heating 1C lower overnight in the bedrooms.)

    However, such a change might put consumption up if you need more heat over the house as a whole - even though the living room is less of a sauna!

    Switch suppliers NOW!  Our annual consumption of 40,000kWh gas and 5000kWh electricity will cost us £1650. You're being robbed.
  • edited 26 March at 3:17AM
    dur77dur77 Forumite
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    edited 26 March at 3:17AM
    Thanks for the reply - yes just switched supplier now, as I was on a Standard variable - we had just moved in after refurbing the place - new boiler, new kitchen, so appliances are all new and should be efficient, and LED lighting everywhere etc. One thing the missus insisted on was electric wiring for underfloor heating - and these are dotted all over the place, in kitchen and bathroom floors - they are on a set temp of 21, with their own thermostats in each room, but we were told these use minimal electricity - maybe I should turn them off, could these be driving high electric usage? The other thing is that she seems to be using the washer and tumble dryer a lot - like daily...!

    That's a good point about the thermostat being in the hardest place to heat - but presumably the costs would be even higher then - if the boiler is being driven by this easily warmed up living room, presumably it doesn't matter about the TRVs and radiators in the other room - they will just switch on and off based on the living room thermostat. We are having to 'overdrive' the thermostat sometimes to get the bedrooms warm upstairs at night - e.g. during day the heating doesn't come on, because it is south facing living room, the thermostat is often reading 22/23 degrees so never comes on. Evening, as the temp drops to 20 degrees the two radiators in the living room kick in and get it back to 21 very quickly. But the bedrooms then still need heating, so we increase the set temp to kickstart the boiler, e.g. driving it to 22 or 22.5 in the living room, to get the rooms upstairs warm enough. But doing this surely just means the boiler is on and off a few more times, but still for shorter periods.
    Its not a smart thermostat - just digital, push button, but it is wireless, so technically we could take it off the wall and put it in another room - although wouldn't this keep the boiler going for longer and therefore increase costs?? Do you think having the boiler itself always 'on' for central heating is causing an issue - presumably it is not using gas unless the thermostat tells it to fire up ?

  • TalldaveTalldave Forumite
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    Yes, the electric underfloor heating could be using a lot.  Try having them off for a week and see what the impact is?  Our place has two bathrooms with underfloor heating but I've not been brave enough to turn it on yet as the rooms get nice and warm from the towel rail radiators.  I also can't get my head around the idea of heating a floor that you spend maybe 10-15 minutes a day on!

    I understand your concern about the consumption going up, but at the same time you're not happy with the heating!  It might be that if you stop overheating the living room whilst getting the bedrooms warmer, the total consumption doesn't change that much - you're just shuffling the warmth around.

    What you really need to do is have upstairs and downstairs separately zoned and then you can control them completely independently from two thermostats with totally different heat/time schedules - but that's going to cost quite a bit to get done (perhaps not as much as your gas was costing though?!).

    In the meantime you can play with what you have. The thermostat needs to be somewhere where the radiator has no TRV - to prevent the thermostat battling with a TRV. 

    Do the living room radiators have TRVs?  If so, I would suggest moving the thermostat to the hall, but as long as the radiator there doesn't have a TRV (or at least set it to MAX). Wind the living room TRVs down a bit and wind the upstairs bedroom TRVs up to MAX or one stop back.  Then see what happens.  It really is a case of trial and error.  If the upstairs radiators take an age to get warm you will need to balance the system to reduce the downstairs flow a bit and force more of hot water upstairs.  I've never done that so can't advise on how to do it properly.

    If the living room radiators don't have TRVs you're a bit stuck for moving the thermostat, since the only control you've then got is to reduce the flow so that room heats up slower whilst others are heating faster - but it still doesn't prevent the room eventually overheating if the rest of the house takes a lot of heat to bring up to temp.

    Before you start of course you need to check that all rads get fully hot top to bottom (bleed them if not) and that the TRVs all work.
  • dogshomedogshome Forumite
    3.4K posts
    Part of the Furniture 1,000 Posts
    Do you have billing records as to the winter Gas consumption in previous years?

    If the 9350 gas Kwh over two months is way in excess of previous years, there are two possibiltys
    1) You have a gas leak - They can occur in areas where the smell isn't detected - With all gas appliance off check the meter
    2)) You have a faulty meter - See post Rogue Meters
  • matelodavematelodave Forumite
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    If it's a new system then ideally you should have a programmable thermostat fitted which would give you a bit more control over timing. 

    As said above, most systems have the thermostat in a room which is heated by a radiator which does not have a TRV or the TRV is wide open - generally the hall because that' the room that takes the longest to heat . The temperature in other rooms is controlled by the TRV fitted to the rad in that room.

    If you do have TRVs on the rads in the room living room where your stat is located then you could try reducing the flow through those rads to increase the amount of time it takes to get the room up to temperature which would allow more time for other rooms to heat up.

    However if I were you I'd get a wireless programmable thermostat. They easy enough to fit,  the receiver is connected at the boiler and the thermostat can then be move around to find the best location for it to control the house. TBH I would have had the system zoned so you could control upstairs and down stirs independentl but it's probably not easy to do now the system has been fitted..
    If the system has been designed properly with the radiators correctly sized to match the heat loss of the room you should not need to use electric underfloor heating which will cost you dearly unless it's only on for very short periods. It uses peak rate electricity which is around 4-5 times more expensive per kwh than gas.

    You need to monitor your gas and leccy meters a bit more often, say once a week to get a better idea of your consumption

    Never under estimate the power of stupid people in large numbers
  • Gerry1Gerry1 Forumite
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    Part of the Furniture 1,000 Posts Name Dropper
    dur77 said:
    One thing the missus insisted on was electric wiring for underfloor heating - and these are dotted all over the place, in kitchen and bathroom floors - they are on a set temp of 21, with their own thermostats in each room, but we were told these use minimal electricity - maybe I should turn them off, could these be driving high electric usage?
    If you wife insisted on a car that needed special petrol costing £6 per litre, would you agree and use it for a lot of your mileage?  What's so special about underfloor heating that justifies spending five times as much per kWh?  The costs certainly won't be minimal !
    dur77 said:
    The other thing is that she seems to be using the washer and tumble dryer a lot - like daily...!
    Again, why pay five times as much??  Time to get a gas tumble dryer ! 
  • dur77dur77 Forumite
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    MoneySaving Newbie
    Thanks all for advice! Unfortunately nothing to compare with as we only recently bought the house and then set about a refurb, replacing the old boiler with new system and doing up the kitchen and bathrooms...
    Will start playing around with the location of the thermostat (it is wireless, they've just stuck it to the living room wall)
    Agreed about the bad move listening to the wife - unfortunately the refurb guys also agreed and said it is cheap as chips and well worth having cos the towel radiators won't heat the room up well enough given the large draughty windows (unless I replaced all the windows, which seemed like a much bigger and expensive job)......I should have done my own research
  • A_LertA_Lert Forumite
    141 posts
    100 Posts
    For the gas, for a 5 bedroom house with heating on 24/7 that sounds plausible for winter bills. It'll be a lot cheaper into the spring and summer.
    Setting the timer to turn the heating off overnight, and come on again maybe an hour before you get up, will save money. With a decent duvet most people will be fine with that, but babies or the elderly might need the heating on 24/7.
    If a room is too hot, use the TRVs to reduce the heat into it.
    Also check the boiler thermostat. This controls how hot the water inside the radiators is. With condensing boilers (which is almost all modern boilers) setting this too hot makes the boiler less efficient. 65C is suggested. But setting it too cold will make the radiators not powerful enough
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