Is this about right?

[DH202020]

We finally moved in on December 3rd after 9months selfbuilding.

Have been monitoring our gas usage and was wondering if this is about right for the type of house built?....

 

Gas Usage: approximately 100m3 or 111kh per month (been cold for SE area).

2x people, living in 72sqm (ground floor)

Underfloor heating one zone only.

Very good floor/wall/roof insulation.

triple glazed.

Gas combination boiler (worc/greenstar 32dci).

2x showers per day

Hob gas only (used infrequently)

House set to 19.5° constant.

 

Does this all add up?

Was hoping gas usage would be less

Anyone with similar design/usage??

Thanks David.

 

[jamiehamy]

What is the build material? If this is measuring over 2 months it'll not be an accurate picture as the fabric on the house will be absorbing the heat even still. 

 

A friend built an ICF house i Essex and said it was really cold for the first 6 months but once the whole building heated up the energy useage dropped massively. 

[Jeremy Harris]

It depends on the true house spec to a large extent, rather than the theoretical spec.  You mention very good floor, wall and roof insulation and 3G windows, but what are the true U values?  Also, you don't mention ventilation, and this can often be the major cause of heat loss in a reasonably well insulated house.  How airtight is your build, what's the air leakage rate and do you have MVHR?

 

As an example, our house would need more than double the heat input if we didn't have MVHR, as the ventilation heat loss is such a large part of the overall loss. 

Edited February 2, 2017 by JSHarris

[SteamyTea]

I assume you mean 111 kWh/month rather than 111 kh.

DHW should be between 1 kWh and 4 kWh /day per person (short shower or full bath).

So if we call that 3 kWh/day for the two of you, that is 90 kWh in DHW, leaving 40 kWh for the space heating.

Seems pretty good to me.

[DH202020]

Just now, jamiehamy said:

What is the build material? If this is measuring over 2 months it'll not be an accurate picture as the fabric on the house will be absorbing the heat even still. 

 

A friend built an ICF house i Essex and said it was really cold for the first 6 months but once the whole building heated up the energy useage dropped massively. 

Hi jamiehamy

MBC timber frame, walls .16, floor .105

It's averaging over a 2 month period about 111kh per month!

[DH202020]

5 minutes ago, JSHarris said:

It depends on the true house spec to a large extent, rather than the theoretical spec.  You mention very good floor, wall and roof insulation and 3G windows, but what are the true U values?  Also, you don't mention ventilation, and this can often be the major cause of heat loss in a reasonably well insulated house.  How airtight is your build, what's the air leakage rate and do you have MVHR?

 

As an example, our house would need more than double the heat input if we didn't have MVHR, as the ventilation heat loss is such a large part of the overall loss. 

Hi Jeremy

 

Similar to yours with MHVR, except our wall is .16

[Jeremy Harris]

ST has cracked it I think.  To thirds of your gas bill is delivering hot water, and 40 kWh/ month for heating in this recent cold weather isn't too shabby for the spec of house.  Our heating  estimate was around 1 kWh/day, with the better insulation level we have, and we're only lower than this because we're in a very sheltered location.  Your heating looks to be around 1.25 kWh/day, which, given the cold weather and the poorer wall insulation seems pretty reasonable.

 

For comparison, our 90m² old house uses around 4 to 8 kWh/day for heating at this time of the year, and around the same as your new house for DHW, provided by a gas combi that is reasonably efficient.

Edited February 2, 2017 by JSHarris

[DH202020]

8 minutes ago, SteamyTea said:

I assume you mean 111 kWh/month rather than 111 kh.

DHW should be between 1 kWh and 4 kWh /day per person (short shower or full bath).

So if we call that 3 kWh/day for the two of you, that is 90 kWh in DHW, leaving 40 kWh for the space heating.

Seems pretty good to me.

Hi steamyTea

 

Yes your right kWh

Ok that's helpful thanks

 

 it all started when I began to check my utility costs, there was a post about this on here the other day....now trying to get comparison... confusing or what!

Come across 'cheap energy club' that guy on the TV...helps to get credit card deals etc.

[DH202020]

9 minutes ago, JSHarris said:

ST has cracked it I think.  To thirds of your gas bill is delivering hot water, and 40 kWh/ month for heating in this recent cold weather isn't too shabby for the spec of house.  Our heating  estimate was around 1 kWh/day, with the better insulation level we have, and we're only lower than this because we're in a very sheltered location.  Your heating looks to be around 1.25 kWh/day, which, given the cold weather and the poorer wall insulation seems pretty reasonable.

 

For comparison, our 90m² old house uses around 4 to 8 kWh/day for heating at this time of the year, and around the same as your new house for DHW, provided by a gas combi that is reasonably efficient.

That's good to hear...

I guess it was my bill that made me question whether good or bad?

BTW When the winter sun comes out it warms the house by around 3° by 3pm...superb

 

Attached is our SW facing bay, the sun has just finished it's run!

[AliG]

As people say that seems a very good result David. It is only around £3 a month of gas in the winter (plus standing charge). Most people would be doing a jig if they achieved that!

Edited February 2, 2017 by AliG

[DH202020]

11 minutes ago, AliG said:

As people say that seems a very good result David. It is only around £3 a month of gas in the winter (plus standing charge). Most people would be doing a jig if they achieved that!

Hi AliG

A MONTH!!

I have roughly worked it out on the tariff I'm on £50 Inc standing and VAT a month... the meter usage on the gas is 100m3 per month...

Please tell me you mean a £3 DAY

[DavidFrancis]

I  think 100 cubic metres is more like 1,110 kWh.  But even that is good compared to our solid-stone walled house where we used about 180 kWh in ONE DAY last week, and that was with the heating set to 16C during the day/night and 18.5C in the evening.

[DavidFrancis]

DH - I cross-posted with you, but 100kWh should cost about £3.00.  But 100 cubic metres on the other hand ....

[AliG]

David is right, I never checked the calculation at the start, but 100 cubic metres is around 1111kWh not 111. All those 1s are easy to mistype.

 

So around £50 a month including standing charge, the gas itself would be around £30.

 

For the winter that is still excellent. My 90s house uses way more gas in winter months than summer. You will probably find your heating isn't on at all for 8 or 9 months of the year.

 

If you are heating around 300l of water a day by 40-50c then DHW is using around 15kWh a day, or close to half your usage.

 

Thus over the year I would expect you to use around 5500kWh for DHW and 2500kWh for heating, assuming roughly 4 months of heating. You may be using more heat than normal at the moment as materials dry out.

 

At 3p per kWh that is £240 for the gas used plus around £100 for the standing charge at around 30p a day. So your average bill should end up being around £30 a month over the year.

Edited February 2, 2017 by AliG

[DH202020]

2 minutes ago, AliG said:

David is right, I never checked the calculation at the start, but 100 cubic metres is around 1111kWh not 111. All those 1s are easy to mistype.

 

So around £50 a month including standing charge, the gas itself would be around £30.

 

For the winter that is still excellent. My 90s house uses way more gas in winter months than summer. You will probably find your heating isn't on at all for 8 or 9 months of the year.

 

If you are heating around 300l of water a day by 40-50c then DHW is using around 15kWh a day, or close to half your usage.

 

Thus over the year I would expect you to use around 5500kWh for DHw and 2500kWh for heating, assuming roughly 4 months of heating. You may be using more heat than normal at the moment as materials dry out.

 

At 3p per kWh that is £240 for the gas used plus around £100 for the standing charge at around 30p a day. So your average bill should end up being around £30 a month over the year.

PHEW... thanks

I will now shop around with confidence, see if I can get a better tariff

[DH202020]

24 minutes ago, DavidFrancis said:

I  think 100 cubic metres is more like 1,110 kWh.  But even that is good compared to our solid-stone walled house where we used about 180 kWh in ONE DAY last week, and that was with the heating set to 16C during the day/night and 18.5C in the evening.

I'm happier now!....although it sounds like you're heating a cathedral?

[DavidFrancis]

No cathedral - eight rooms exc shower/bath/utility rooms.  But overall our gas/electricity bill for the year is about the UK average, I think.  Approx £900.

[AliG]

Yes, that is similar to my winter bills for a 4000sq foot 90s house. I am around £1500 a year for gas. A lot of that goes on DHW and a gas tumble dryer.

 

I once looked at a 6000sq ft stone house in Edinburgh. They said the gas bill was £700 a month! The U-value of those old stone walls is around 2 which is worse than a modern double glazed window.

[Ferdinand]

I was surprised at my readings for 1 Nov 2016 to end of Jan 2017.

 

Elec use is 1400 kWh which at 12p/unit is about £ 170.

Gas use was 6330 kWh which at just under 3p/unit is about £170 also. 

 

That felt high (2000 sqft house 2007-9 bungalow gobble) as I am looking for a bill of about £750 for the year (*).

 

But then I remembered that we always used to say that the winter quarter = 40% approx, and it has been cold plus we have been running a couple of degrees high for visiting family for several weeks, so I think I can live with it.

 

(*) Worth a note that this was £1400-1500 3 years ago; cut by various means including switching and a big solar array.

 

@AliG

Quote

I once looked at a 6000sq ft stone house in Edinburgh. They said the gas bill was £700 a month! The U-value of those old stone walls is around 2 which is worse than a modern double glazed window.

 

Our previous house was a 5000 sqft listed effort, and it was dead easy to get to a 5k a year bill for elec (storage heaters - no gas). I think the major unnecessary bills are for people in normal sized houses paying £1500-£3k a year, and that there are a *lot* of them.

 

Ferdinand

 

Edited February 2, 2017 by Ferdinand

[PeterW]

29 minutes ago, Ferdinand said:

But then I remembered that we always used to say that the winter quarter = 40% approx, and it has been cold plus we have been running a couple of degrees high for visiting family for several weeks, so I think I can live with it.

 

From working previously in the dim and distant past, the quarterly breakdown of charges used to calculate your DD payments (for a monthly DD) are along the lines of this below :

 

Q1	Jan-Mar	38%
Q2	Apr-Jun	24%
Q3	Jul-Sep	17%
Q4	Oct-Dec	31%

 

Yes - they don't add up to 100%...! The systems used to use either a 13 month year (gas), or an additional 10% consumption (elec) to allow for cost increases and customers low balling their consumption. Using that it is pretty easy to calculate what you "should" be getting in the remaining quarters of the year.

 

 

[DH202020]

4 hours ago, Ferdinand said:

I was surprised at my readings for 1 Nov 2016 to end of Jan 2017.

 

Elec use is 1400 kWh which at 12p/unit is about £ 170.

Gas use was 6330 kWh which at just under 3p/unit is about £170 also. 

 

That felt high (2000 sqft house 2007-9 bungalow gobble) as I am looking for a bill of about £750 for the year (*).

 

But then I remembered that we always used to say that the winter quarter = 40% approx, and it has been cold plus we have been running a couple of degrees high for visiting family for several weeks, so I think I can live with it.

 

(*) Worth a note that this was £1400-1500 3 years ago; cut by various means including switching and a big solar array.

 

@AliG

 

Our previous house was a 5000 sqft listed effort, and it was dead easy to get to a 5k a year bill for elec (storage heaters - no gas). I think the major unnecessary bills are for people in normal sized houses paying £1500-£3k a year, and that there are a *lot* of them.

 

Ferdinand

 

Even at the smaller usage end of the market I am swapping from E.on to Iresa (small provider) no tie in, saving around £160 dual fuel per year

Looks easy enough....to swap!

 

Guestamating yearly costs somewhere around £712? (Will be our1st year)

Thanks for all who have contributed to this thread, appreciated.

David.