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Posted

I have done an experiment this year, it involves not turning my storage heaters on.  I now just use a fan heater when and where I need it.  This is very easy for me as I live alone.

The headline figures are below.

 

Jan 2024, Mean Power 0.75 kW, Energy Usage 543 kWh, Max Power 8.9 kW, Mean Power >0 0.94 kW, Mean Internal Temp 21.3°C, Mean External Temp 4.5°C, ΔT 16.9K, Zero Power 32%

Jan 2025, Mean Power 0.44 kW, Energy Usage 329 kWh, Max Power 4 kW, Mean Power >0 0.55 kW, Mean Internal Temp 17.4°C, Mean External Temp 4.8°C, ΔT 12.6K, Zero Power 43%

 

So around 60% of the energy usage, but with a lower internal air temperature of 4K.  This lower temperature is not a problem in reality as I am out at work a lot, and can just switch the fan heater on and the room is up to temperature in a few minutes.

On a daily basis, in Jan 2024 I was using 17.5 kWh.day-1, Jan 2025, 10.6 kWh.day-1 (I was aiming for 10 kWh.day-1, so close).

Now this will affect my costs as I am on E7 and EDF has not fully published all my data yet.  But last year I paid £118.81 and this year (excluding yesterday), £87.34 (So 74% of the price this year).

So even allowing for the higher day unit price, but still heating my water in the E7 window, I have saved 26% in cash terms.

Now rates have changed in the last year.

Jan 2024, Standing Charge 62.46p.day-1, Day Rate 36.72p.kWh-1, Night Rate 14.68p.kWh-1

Jan 2025, Standing Charge 71.22p.day-1, Day Rate 31.473p.kWh-1, Night Rate 12.574p.kWh-1

 

So 14% increase on Standing Charge, -14% Day Rate and -14% Night Rate.

I will look at this again when I have all the numbers in and see what is really happening with the price changes (I can look at the weighted averages at the half hour).

 

Still, I saved £31.47, or about a third of the price of the speeding ticket I am about to be issued with for doing a reckless 27 MPH.

 

 

  • Like 1
Posted

Good analysis - I’ve been doing the same…..

 

last year (Act Nov 2023 to Nov 2024) I used a total of 8,250 kWh of gas for CH, HW and cooking heating to a tight schedule and putting up with a wide range of temps in different rooms - SWMBO did not like this heating regime at all and was rather vocal about it - she especially didn’t like going into rooms heated to a lower setback temp because used infrequently and as far as she was concerned the house was never warm enough - esp the living areas despite them being 21 to 22 deg C

 

In Dec 2024 I went 24/7 heating with a much narrower difference between rooms (whole house roughly same temps - little lower in bedrooms and higher in bathrooms and living areas but interestingly at a lower set point 20.0 for living areas) Majority of Rads have TRV’s set to an elevated target (limiters) Boiler is running WC and room temps are managed by a constant flow rate thro the rads at a low flow temp rather than TRV influence at higher flow temps

 

I’ve worked out based on 2 mths data that this change is going to cost me an additional £65 a year……

 

That I am very happy to pay it’s a cheap price to pay for improved comfort levels and a very very quiet wife 😉

Posted

@marshian

The last 3 years my usage has been very stable, and I thought I had just about done all the passive improvements I could (I have secondary glazed, on the double glazing, a couple more windows and am going to improve the loft insulation), so it is interesting to see how much just a different heating regime could change things.  And it is better than I thought.

I do have the advantage that the weather is very mild down here, and no one else in the house.

Posted
37 minutes ago, SteamyTea said:

Still, I saved £31.47

If you used a different tariff would the saving be better?

Posted
2 minutes ago, JohnMo said:

If you used a different tariff would the saving be better?

Not sure.  The reason I started monitoring my energy usage was to answer that question.  That was nearly 16 years ago.

Apart from finding a cheaper tariff, rather than a different ToU one, I could not make the numbers stack up.  But until last year I was working evenings, and now I work days, that will have changed things a bit.

I will always be heating water though, and that 30 quid saving is really just the space heating saving.

At the end of next month, I will have more data and will be able to do some real modelling, 30 days data is not enough to base a decision on.

Posted
15 minutes ago, SteamyTea said:

@marshian

The last 3 years my usage has been very stable, and I thought I had just about done all the passive improvements I could (I have secondary glazed, on the double glazing, a couple more windows and am going to improve the loft insulation), so it is interesting to see how much just a different heating regime could change things.  And it is better than I thought.

I do have the advantage that the weather is very mild down here, and no one else in the house.


last 3 years I’ve driven my gas usage down from 16,500 kWh a year mainly with insulation improvements and a bit of tech

 

East Anglia is also quite mild compared to up north but not as mild as the pigs front legs so you definately have an advantage there. 
 

Increasing Loft insulation is my current project - can only do it in the winter as even in the shoulder months the loft temp with a large area of south facing roof space gets unbearable - going from a varable insulation level (patchy 70mm in 60% of the loft area and 200mm in the other 40%) to 320 mm everywhere but it’s slow going as I’m having to remove all the loft boarding

 

Living alone is a huge advantage if your temp tolerance is quite high - mine is and I comfortable at 18 deg C unfortunately SWMBO isn’t and that means a compromise - I prefer a compromise that results in less noise 🙂

Posted (edited)
31 minutes ago, marshian said:

last 3 years I’ve driven my gas usage down from 16,500 kWh a year mainly with insulation improvements and a bit of tech

When I first moved here, I was burning though about 11 MWh.year-1 last 3 years has been around 3.192, 3.352 and 3.075, so fairly stable and no loss of comfort.

 

A few years ago I added an extra 0.15m of mineral wool to the loft, but did not really see the advantage, though on the few snow days we have had, I notice that my roof is the last to loose it.

I managed to pick up some Celotex and started to pull up the loft boarding, remove the insulation, fit a VCL, lay the Celotex and am now waiting for free time and enthusiasm to do the rest.  Only done a couple of metres squared.  I was up there for about 9 hours with a 2 kW fan heater on, made it a comfortable working temperature, but 60p.hour-1 which hurts me.

I do have a hole in the roof felt (after neighbours had roof replaced) that needs repairing, but it means I have to shuffle a load of stuff about and wiggle my body into place to glue a repair patch in place, and to be honest, I want a dry day for that.  Today is dry, as was yesterday, so I am going out.

 

Here is a chart of what has happening

 

image.thumb.png.56edb5cef7fa2b30be2758e3bce95669.png

 

And Jan 2024 (note scale changes)

 

image.thumb.png.5d5d28166b08bfe1dcc2a6c53af7681e.png

 
 
 
Edited by SteamyTea

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