High gas usage bill?

[plastics77]

Hi - hope someone can give some advice!
Have had a vaillant ecotec 630 installed with unvented cylinder, mains pressurised supply with digital thermostat in the living room. It is a 5 bed, 3 bath house.
The dual fuel bill for 2 months was £600, 545kWH per month for the electricity and 4,640kWH per month for the Gas.
It seems like the Gas is much higher than it should be.
The boiler is 'switched on' constantly for central heating but is driven on and off by the digital thermostat, which is set at 21 degrees. The room gets warm quickly so reaches 21 quite easily. The heating to the rest of the house is driven by this thermostat - so all the other radiators in the house are on maximum output with individual valves but will only heat up when the living room thermostat is below 21.
The hot water is set to come on for 2 periods, 30mins early morning, 30 mins in the evening.

Is this an abnormal level of gas consumption? Anything I am missing here?

 

[Murdoch]

Have you compared month for month readings over the last couple of years?

 

[Last Plumber]

I think that Gas bill equates to around 50 hours per month but I did only do a quick calculation so might well be wrong. See what others think!
The Electric bill looks high to me but again, only my first impression. What have you got running on electricity? Anything big?

 

[Murdoch]

The Electric bill looks high to me but again, only my first impression. What have you got running on electricity? Anything big?

The lecky bill, based on the Kwh, looks about right for a 4 bed house, with 4 occupants, with the normal kitchen accessories such as dishwasher, tumble dryer, oven and fridge freezer. Electric underfloor heating would make it higher still

This figure is very similar to ours before I installed PV

Its the consumption to look at and then the rates you pay for the lecky .........

 

[EvilDrPorkChop]

For our 4 Bed Detached house that's very well insulated with a smart TRV valves we roughly use 2300Kwh in Gas during a cold winter month. That's with 2 occupants for the HW usage.

So your 4600Kwh for a much larger house with standard controls and probably more occupants it's probably not a millions miles off.

 

[Murdoch]

Having your central heating set to 21 degrees when you are out seems a little wasteful (assuming you are "normally" working)

 

[EvilDrPorkChop]

Having your central heating set to 21 degrees when you are out seems a little wasteful (assuming you are "normally" working)

Suppose it depends on your house.

I have our heating on all day even though we both work as it uses less gas!

 

[Chuck]

Is this an abnormal level of gas consumption? Anything I am missing here?

Check your figures are 'per month' and not for the whole two month period. Also check that they are based on actual readings not the fuel company's estimates.

IMO the electricity looks okay assuming a family of four. Gas is on the high side but if you have a house with so-so insulation and are in a relatively cold (or windy) part of the country it's par for the course.

The only common 'faults' causing a high gas consumption are (a) a leak in the hot water, (b) an incorrectly set house thermostat. (a) is ruled out because you only have the HW on 'heat' for an hour a day, so that's only going to be ca 25 kW hr / day, which is insignificant as your total is 153 kW hr / day. (b) would mean that the house feels uncomfortably warm the whole time. (In my opinion, a house that is heated to 21°C 24 hr/day everywhere is a bit on the warm side so you might want to tweak your TRV's.)

With that gas bill, it might be worth getting a heating engineer to do an energy survey (or do your own using one of the online guides) to see if there are any cost effective measures that can reduce it a bit.

 

[Murdoch]

People always under estimate the benefit of loft insulation - its the cheapest improvement you can make and has the quickest pay back period

 

[plastics77]

Thanks all for the advice. At the moment we are all in, but pre-Covid - which the bills reflect - wife is on maternity leave, so have a baby, both their during the day and a 4 year old who is usually at school, I'm at work.

Electricity wise - there seems to be daily use of washing machine, dryer but nothing else too abnormal. The refurb guys stuck in electric underfloor heat mats/wires in kitchen and 3 bathrooms, with their own thermostats set at 21 for morning and evening parts of day, but off otherwise.

Haven't got previous months readings, as we recently moved in and replaced the old boiler with a new system - the thermostat has been put in the warmest room, downstairs living room- which means during the day

The figures are definitely per month - it was a bill covering 60 days, so roughly 2 months, just divided the total by 2!

In terms of whole house being heated to 21degrees - the wireless thermostat has been placed in hottest southfacing room of the house, the living room - so during the day it hardly ever falls below 21 and therefore the boiler hardly ever kicks in (even though at the actual boiler controls, heating is switched on at 'continuous', apparently the thermostat controls it coming on and off, so I don't need to worry that it is set at continuous at the source?). However, at night, again it warms up quickly as there are 2 radiators on max TRV settings in that living room, so it gets to 21 very quickly and then switches off - but the rest of the house, upstairs bedrooms stay a bit colder even though their radiators TRVs are also on max - so we end up having to 'overdrive' the thermostat in the evenings, re-set the target temp to say 22 or 22.5 to get the boiler to kick in and finish warming up the bedrooms upstairs....maybe that is the issue?

Agree also about the rates, have just switched provider, hopefully that will bring the bill down,

 

[Murdoch]

Thanks all for the advice. At the moment we are all in, but pre-Covid - which the bills reflect - wife is on maternity leave, so have a baby, both their during the day and a 4 year old who is usually at school, I'm at work.

Electricity wise - there seems to be daily use of washing machine, dryer but nothing else too abnormal. The refurb guys stuck in electric underfloor heat mats/wires in kitchen and 3 bathrooms, with their own thermostats set at 21 for morning and evening parts of day, but off otherwise.

So 2 adults and 2 young children with 3 bathrooms with underfloor heating - I think you should turn off the bathroom you don’t use and look closely at how the others are set up time wise ..... and probably reduce the hours they are on

As for the kitchen, if it’s big and the underfloor heating is the only heating, then you’ll have to get used to high electricity bills ....

 

[Chuck]

In terms of whole house being heated to 21degrees - the wireless thermostat has been placed in hottest southfacing room of the house, the living room -
[...]
....maybe that is the issue?

As you suspect, the setup you describe is not ideal. You don't have the thermostat in a 'representative' place but the most extreme one. I'd want to consider other locations less influenced by solar gain, the hallway near the centre of the house a common choice assuming there is a radiator in the same area. Install TRVs in the living room so that the radiators in there are cut back once its up to 21 degC but the thermostat in the hall will keep the heating on for the rest of the house.

If the thermostat is in the hall, the radiator there will need to have its TRV replaced with a lockshield valve. I would also strongly suggest you upgrade the device to a combined thermostat and 7-day programmer.

I would expect changes along the lines I've suggested to save up to 10% on your gas bill.

I will also echo what others have said, electric UFH is a nice but has very high running costs simply because electricity from the grid is about five times the price of gas per kW hr.

There is a limit to what one can do with system 'tuning'. If, as seems to be the case from your description, you are heating room(s) that are unecessarily hot or unused just to keep the boiler running there is definitely scope for savings.

 

[gmartine]

Trim down your living room (datum) rads so they don't warm up as quickly (reduce lockshields to a quarter of a turn, increase as necessary) so that the rest of the house gets a chance to heat up.